Archive for February 2012
by B.B. Pelletier
This question came in last week in the form of a comment about pellet sizing. Pellets are sized by pushing them through a die, and it used to be popular to do it in the 1970s. Shooters eventually realized that the bores of their airguns were doing the same thing, and sizing wasn’t really necessary.
Pellet head size is a different topic that’s still very relevant, so today we’re going to look at what’s involved. It all begins in the past, when conical bullets were first used in firearms in the 19th century.
Conical bullets are longer than they are wide, so they weigh more than the round balls that served as bullets for several hundred years. But because they’re longer, they can also create more friction with the bore. When they’re loaded from the muzzle, this is a problem because it takes so much more force to seat them down on the powder that the effort will usually distort their noses, adding nothing to accuracy.
One early solution (ca. 1835) was the picket bullet, which is also called the sugar-loaf bullet due to its shape. It contacted the bore only at a narrow band near the base of the bullet. The rest of the side of the bullet did not touch the bore and, therefore, did not create any friction. Picket bullets were far more accurate at long range than round balls of the day. They pushed the maximum distance for accuracy from about 200 yards out to 330 yards. And they were also heavier in a given caliber, so they were deadlier on game in calibers that were too small for round balls. A .38-caliber round ball might be marginal for whitetail deer, but a .38-caliber picket bullet would be fine.
The picket bullet looks like a large piece of candy corn. It was a big advance from the round lead ball. Image from Ned H. Robert’s book, “The Muzzle-Loading Cap Lock Rifle.”
But there was a problem. If you tilted the picket bullet during loading — something that was all too easy to do, it left the bore in a tilted position, allowing gas to escape unevenly at the muzzle. That caused it to fly wide of its mark. Picket bullets were considered very accurate but also very difficult to load correctly.
You can see how an incorrectly loaded picket bullet would cause inaccuracy. Image from Ned H. Robert’s book, “The Muzzle-Loading Cap Lock Rifle.”
Straight-sided conical bullets were tried next, but shooters quickly discovered all the problems associated with friction that are mentioned above. Something was needed that would seal the bore against gas loss yet not create excessive friction at loading. Remember, too, that barrel makers were tapering their bores at this time, so that did help a little — but it wasn’t enough.
The next innovation was a bullet that fit the bore at its base, but rode on top of the lands for most of its length. A bullet with two diameters! This bullet worked very well and because it did, it increased the distance at which conical bullets were accurate from about 30 rods (330 yards) out to 1,000 yards.
The two-diameter bullet has a nose that rides on top of the rifling. If it’s sized correctly, this can be a very accurate bullet. Image from the “Lyman Cast Bullet Handbook, 3rd Edition.”
By the time breechloading rifles started coming into popular use (around 1850), the issues of bullet friction with the bore ceased being such a problem, so straight conicals continued to be used, as did the new bullets with bore-riding noses. The picket bullet even remained in limited used through about 1880 for handmade muzzleloading rifles.
A typical conical bullet has parallel sides and a short nose. Image from the “Lyman Cast Bullet Handbook, 3rd Edition.”
Black powder has one characteristic that smokeless powder lacks. When it ignites, it does so instantly, imparting a hammer-blow to the base of the bullet in front of it. Shooters of this era counted on the obturation — a blockage caused by expansion of the bullet bases to help seal the bore.
In the late 1800s, a world champion marksman, Dr. Walter G. Hudson, designed a bullet for breechloading rifles that mimicked the properties of a conical bullet in a black powder arm. Dr. Hudson, who was also one of the men who invented the gas check for bullets, designed a bullet of two diameters. The rear bands of the bullet were exactly bore-sized, while the remainder of the bullet was sized exactly to ride on top of the rifling without being engraved. This bullet didn’t tilt while it was in the bore if it was correctly sized.
Dr. Hudson shot his best matches with the new smokeless powder that didn’t obturate the base of the bullet. So his bullet went into the bore already obturated! It was an advancement that would have had far-reaching consequences if it hadn’t been replaced almost immediately by the new smaller-caliber jacketed bullets that went even farther and were more accurate at long range.
This kind of bullet must be handmade for each gun based on precise bore measurements, plus it cannot be loaded into a cartridge because the base bands are too large to allow the cartridge to be loaded into the chamber. The bullet must be loaded into the bore first, followed by a charged cartridge case that has no bullet.
Dr. Hudson’s bullet has two driving bands at its base that fill the bore of the gun. The forward bands ride on top of the lands. Though it’s difficult to see, the base bands measure 0.383 inches, while the forward bands measure 0.376 inches.
You may wonder what the difference is between the Hudson bullet and the two-diameter bullet. The Hudson bullet has bands and grease grooves that ride the rifling. The two-diameter bullet rides the rifling with a solid nose and no bands.
Pellets and their heads
Which brings us to the subject of diabolo pellets and their head sizes. In target guns, it’s considered ideal if the pellet is sealed by the skirt, which also takes the rifling, while the head rides either on top of the lands or is just barely engraved by them. It’s this “just barely engraved” phrase that causes target shooters the greatest concern. How much is enough? There’s really no way of knowing except by shooting the pellet and seeing the results.
Impossible to make every barrel the same size
Some shooters think that because barrels are made by button-rifling or by hammer-forging they can all be made identical, but they can’t. It’s impossible! Every barrel will respond differently to the passage of the rifling button. While the differences are minute, perhaps in the range of ten-thousandths of an inch, they’re still there and they do affect how the barrel turns out.
The goal for target shooters is to find pellets that group the best in their guns. We believe that these will be pellets that are either lightly engraved on their heads or perhaps are not engraved at all, but they do ride on top of the rifling with no tolerance. From the picket bullet discussion above, you can now see how tilting inside the bore would be a bad thing.
All pellets come with certain sized heads, and all true target pellets (not just those with the name “target” in their title, but pellets that are really controlled during manufacture) have their head sizes printed somewhere on their tin. It will be on a paper label most of the time — and you might have to look hard for it — but if it’s a real target pellet, the head size is there.
The paper labels on the back of two target pellet tins show the head sizes. In Europe, a comma is usually used in place of a decimal that we use in the U.S.
…you can now see how tilting inside the bore would be a bad thing.
Don’t stop yet!
If barrel makers cannot make every barrel the same, what does that say about pellet manufacturers that make tens of millions of pellets every year? That’s right, their pellets do have manufacturing differences. Even though it says a certain head size on the label, there’s no guarantee that every pellet inside the container is exactly the same. And, in the case of certain sloppy manufacturers, the head size might not even agree with what’s on the label.
Airgunners who are target shooters are fanatical about selecting their pellets. They try all the known good brands. If they have a good sense of what head size their gun likes, they might restrict their search to just that size; but often they’ll go both larger and smaller, to make sure they’ve checked everything. When they find the best pellet, they buy 25,000 or more, which will get them through a season of competition and practice.
Because this is such a chore, target shooters will often buy different lots of good pellets of different head sizes and trade them with other shooters. When they find the one best pellet for their gun, they then sell or trade the rest of the pellets they bought and buy a huge lot of the one right pellet.
Head size matters — sometimes
So pellet head sizes do matter — sometimes. But not for everyone. A guy who shoots an RWS Diana 34P for recreation would be wasting his time going through all the trouble I’ve outlined here. He only needs to find a pellet that works, and then shoot just that one pellet. And for most of us, that’s all you need to be concerned with.
When I test airguns for you, I usually don’t even bother to look at the head size. Indeed, a great many sporting pellets don’t even have their head sizes indicated. You can assume that it’s about 4.50mm, because that’s the size that seems to work the best for most guns. And unless you start shooting in competition or at very long ranges, that’s all you have to be concerned with.
Today, I’m going to do a fundamental report that I promised some time back. I’ll show you how a spring-piston powerplant works. I’ll also show you how to measure mainsprings so you can find replacements when yours wears out. We had a question yesterday morning from a blog reader named Peter:
Hi Tom! Been trying to locate a replacement spring online for about the last six months. What I have is a pre-war Diana model 45 underlever. I have read on different blogs that springs from other guns can be used; but when contacting these spring suppliers, they say that if it’s not in their online catolog it’s not available. At any rate, there must be someone, somewhere that would be willing to sell a spring that would work in this gun. What baffles me most is there must be hundreds of other people who have located springs for their old airguns, but in six months of searching have had no luck in locating their source. Tom, I need your help before I go completely bazonkoos!!!
Well there’s not much chance of a pre-war Diana airgun mainspring being available anymore, is there? World War II ended in 1945, which was 67 years ago, and the chances of finding a new old-stock mainspring are virtually impossible. However, all is not lost. There are plenty of mainsprings around today that can be made to work. All you have to do is measure the old spring, so you know what’s needed. I’ll come back to this, but first I want to discuss how the spring-piston powerplant works.
The spring-piston powerplant
There are a number of ways they can work, but the basics of the spring-piston powerplant is a spring pushing a piston that compresses air that then pushes the pellet. That’s it in a nutshell. There are no valves or moving parts, other than the piston and mainspring. The air is compressed ahead of the piston in a part of the spring tube called the compression chamber.
In the end of the compression chamber, there’s a hole called the air transfer port. It’s where the compressed air leaves the compression chamber and gets behind the pellet, because the breech is in line with the transfer port.
This side view of two air transfer ports shows how they work with the piston to channel high-pressure air behind the pellet. The port may be offset compared to where the breech is located in relation to the compression chamber.
This drawing shows how the pellet seals the end of the compression chamber, which is on the right in this view. The compressed air has nowhere to go, other than behind the pellet.
This Beeman R1 rifle has a special replaceable transfer port installed. That’s the reason the Allen screw is on top of the spring tube. But the transfer port here looks like most breakbarrel transfer ports.
When a spring gun is fired
Most spring guns, including those with gas springs, work the way I’m about to describe. When the gun is cocked, the mainspring is compressed by the piston, which is held in the rearward position by the sear. When the trigger releases the sear, the piston springs forward, compressing air as it goes. When the air is fully compressed it stops the piston before it hits the end of the compression chamber.
On some guns that aren’t properly designed or guns that have been tuned incorrectly, the piston actually slams into the end of the compression chamber because the air pressure isn’t high enough to stop it. This is why some pellets feel much harsher than others in a spring gun — because they either move too soon and are unbalancing the powerplant (allowing things to happen that shouldn’t) or they remain in place too long, allowing the piston to rebound off the high-pressure air in the compression chamber.
This is the question that started this report. A reader asked me to show what a spring-piston powerplant looks like. This is it, except for the outer spring tube.
These are the major parts of a spring-piston powerplant. They fit inside the spring tube and the mainspring fits inside the hollow piston. It also fits over the spring guide, which is shown in front of the trigger. Some guns also have a shorter spring guide at the front of the spring that fits inside the piston. Because of its shape, it’s called a top hat — shown above the end of the spring.
The piston is hollow, as you can see here. The mainspring fits between the central rod, which is used to engage the sear and the inside of the piston. The better the fit here the less the gun will buzz. A tin soda can could be cut to make a liner to fit inside the piston and take up any slack between the mainspring and the piston.
Here you see the piston in the cocked position. The trigger has caught the piston and will hold it in place until the trigger is pulled. The spring guide is not shown here so you can see this relationship, but it would be against the front of the trigger and extending into the hollow piston, inside the spring. The piston rod that you can see passes through the spring guide.
How to measure a mainspring
Pete asked where to get a mainspring for his pre-war air rifle. I told him he’ll have to get one that is close and make it work, Let’s take a look at what that means.
There are several measurements you need to know when measuring mainsprings. One is how fat the spring is on the outside, so you can determine if it will fit inside a piston. Be careful with this one, though, as springs will buckle when they’re compressed and become wider than they measure at rest. Always allow yourself some wiggle room until you get the hang of it.
The second measurement is the inside diameter of the spring. It has to fit over the outside of the spring guide and top hat, if there is one. You want the fit of the spring over the rear spring guide to be very tight or “nailed on” as Jim Maccari says. The spring will get a trifle wider when it’s compressed, so don’t worry if it’s very tight — as long as it fits over the guide.
Lastly, you need to know how long the mainspring will be when it’s fully compressed. That helps determine if you’ll be able to cock the gun or the spring will become coil-bound before the sear grabs the piston. Look at the picture of the piston in the cocked position above. The compressed mainspring has to fit in the space provided when the piston is in that position and the spring guide is in place.
This graphic tells you how to calculate the compressed length of a mainspring.
What if the spring is too long?
You can live with a spring that’s too long, as long as all the other measurements work. When the spring is too long, you cut off some coils to make it fit. I use a Dremel tool with a cutoff wheel for this, and I cut with the wheel at 90 degrees to the axis of the spring wire. Then, if I want a beveled end, I can grind the end of the spring on a bench grinder to get it flat again.
I don’t bother to collapse the last coils of the spring the way they come from the factory, but if I wanted to I would heat them red hot and whack them with a hammer until they bunch up. I would have to use heat-sink paste or a good wet towel above the spot where the spring was heated to prevent more of the spring wire from softening this way. Then I would quench the job in water when it was completed. But like I said, I don’t bother doing that and my springs seem to work fine.
Where to get mainsprings
Now that you know how to measure a mainspring, you probably want to know where to buy them. I know of three possible sources. First is Pyramyd Air, which sells many replacement springs for current and obsolete models. Some of the old Weihrauch, FWB and Diana mainsprings can be modified to fit many older airguns. The HW55 mainspring and the FWB 124 mainspring are both quite long and can be cut to fit many other guns.
The second source is John Groenewold, of JG Airguns. Contact him at http://www.jgairguns.biz. John buys vintage parts in the UK for many old classic airguns and often has parts for those oddball guns. He may even know if he has a spring that will work for you, even if it isn’t commonly listed anywhere.
Third and perhaps the best of all is Jim Maccari, also known as the Springman. Visit his website at http://www.airrifleheadquarters.com. Jim makes springs for many older airguns, plus he can sometimes find a spring that will serve for something other than what it was made for.
by B.B. Pelletier
Today is velocity/power day for the Evanix Conquest PCP air rifle. In a reversal of the norm, I tested the rifle for accuracy first, and this is a follow-on to that. Of course, now we do know which pellet works the best in the test rifle, but I will also test it with a couple others to get the true power potential.
First test: JSB Exact 15.9-grain domes
The rifle was filled to 200 bar before the test began. The first pellet I tested was the one we know to be the most accurate — the JSB Exact 15.9-grain dome. Since this is the pellet I would chose for this rifle every time, the results of this test will give me realistic performance parameters of the rifle as I would use it. I’ll be testing velocity, which translates to power, and also the useful shot count. Velocity comes first.
The first string of 10 shots gave an average 955 f.p.s. The high was 960 and the low was 948, for a total spread of 12 f.p.s. At the average velocity, the rifle produces 32.21 foot-pounds of energy at the muzzle.
Please notice that we already know the rifle is most accurate at this speed. This relates directly back to what we learned in the Pellet velocity versus accuracy test. Now we know that harmonics and not velocity are the most influential forces when it comes to airgun accuracy.
The average velocity of the second string of 10 shots was 948 f.p.s., with a spread from 943 to 954 f.p.s. That’s a spread of 11 f.p.s., which is one foot per second less than the first string. It’s still a good, tight velocity range; and we know from the accuracy test that the rifle is just as accurate on the second string as on the first. The full-auto group that amazed us all was fired on the second string of 10 shots. At this velocity, the rifle generated an average of 31.74 foot-pounds of energy, so not much difference between this and the first string.
The third string of 10 shots averaged 944 f.p.s., which is a small drop from the first 10. The low was 927 f.p.s., and the high was 949 f.p.s. The total spread opened up to 22 f.p.s. That’s still reasonable; but if you lump this string in with the first two, the total spread is now 33 f.p.s. That’s still a good spread for accuracy at 50 yards, yet the third string was where the groups opened up a little and also dropped on the paper a little. On this string, the average muzzle energy was 31.47 foot-pounds, which is still very respectable.
The fourth string of 10 shots averaged 924 f.p.s. and ranged from 915 f.p.s. to 932 f.p.s. This spread spans a total of 17 f.p.s. The average muzzle energy was 30.15 foot-pounds. Again, it’s a fairly tight string; however, if you throw it in with the first three strings, you get a total velocity spread of 45 f.p.s. That’s too much of a spread for a smallbore pellet rifle to be accurate across 40 shots at 50 yards. And it was seeing the results of the fourth string during the accuracy test that made me stop after 3 strings of 10. The point of impact dropped over an inch and the groups all opened up to twice what they were in the first 2 strings.
If you’re shooting the Conquest at 50 yards and going for the ultimate in precision, refill the rifle after 20 shots. But if you’re just shooting casually at 35 yards, you should be good all the way to 40 shots. After that, however, the velocity starts to drop rapidly.
After 43 shots, the onboard pressure gauge reads about 130 bar remaining in the gun. The gauge is too small to be more exact than that. When I refill the gun, the reservoir inlet valve opens at around 2,150 psi on the large gauge on my carbon fiber tank.
Okay, this first pellet has taught us a lot about the Conquest. We now know the power, the velocity and the shot count. But we’re not finished testing the rifle.
The Conquest has a shrouded barrel, and on the rifle range it is quieter than a .22 rimfire. But it’s not a quiet airgun. I rate the discharge noise at a solid 5 according the scale Pyramyd Air uses on their site. Nothing short of a big bore or an AirForce Condor is as loud — despite the shroud. So, this isn’t an air rifle for the suburban backyard or shooting in the house.
Second test: Eun Jin 28.4-grain domes
The second test was with the 28.4-grain Eun Jin dome. Because the Conquest is a pneumatic rifle it should give the highest power of which it is capable with the heaviest pellet. Being a magazine-fed repeater, also, we have to be careful to choose pellets that actually fit and work in the magazine, but that was already done at the range.
With a drum magazine, the fit we’re concerned with is the length of the pellet. Will it fit the chambers and not protrude on either end, which would tie up the action when the rifle tries to advance the magazine to the next pellet? The 28.4-grain Eun Jin both fits the magazine of the Conquest and works well. The accuracy was only acceptable — in the 1.25-1.5 inch range for 10 shots at 50 yards, so I wouldn’t use it in this rifle unless there was nothing better.
The rifle was again filled to 200 bar for this string. The average muzzle velocity was 697 f.p.s. for 10 shots. The low was 691, and the high was 707 f.p.s. At the average velocity, the rifle generated 30.64 foot-pounds of energy at the muzzle. That is lower than I expected, as PCPs generally become more powerful with heavier pellets — but that’s what it did.
Third test: Beeman Kodiaks
Next, Beeman Kodiak pellets were tested. In .22 caliber, these weigh 21.1 grains and would be ideal for a rifle of this power. But they don’t group as well as the 15.9-grain JSBs, and that has to be the most important criteria. Out to 50 yards, they’re okay. Beyond that, they can’t keep up.
Kodiaks averaged 819 f.p.s. for 10 on a fresh fill. The low was 813, and the high was 825 f.p.s. At the average velocity, they produced 31.43 foot-pounds of muzzle energy. Again, the heavier pellet wasn’t as powerful as the lighter one.
Fourth test: JSB Exact Jumbo 18.1 grains
The last pellet I tested was the 18.1-grain JSB Exact Jumbo heavy pellet. They averaged 895 f.p.s. on a fresh fill, with a low of 891 and a high of 901 f.p.s. At the average velocity the rifle, produced 32.2 foot-pounds of muzzle energy with this pellet. So, it equals the 15.9-grain pellet for power, but not for accuracy, as we have seen.
The trigger of the test rifle releases at a very consistent 1 lb., 10 ozs., but the release is different than any other trigger I’ve ever felt. If you squeeze slowly, you’ll feel the solenoid fire an instant before the gun fires. It’s a small click before the boom. The actually firing is felt as a prolonged forward cycling of the bolt to push the pellet into the breech and back again to clear the magazine. The feel through the trigger while the gun fires is long and sloppy, but as you saw in the accuracy test, it works well and doesn’t affect the hold at all.
Bottom line thus far
The Conquest is stacking up to be a fine hunting air rifle. It’s powerful and amazingly accurate in the .22-caliber version I’m testing. And I’d like to mention that all the pellets tested fed through the magazine with no problem. Sometimes a rotary magazine like the one on the Conquest has problems accepting longer pellets, but even the big Eun Jins fit this one.
Without question, the one best pellet for our test rifle is the 15.9-grain JSB Exact dome. It’s not only more accurate than the others, it’s also more efficient, which was a surprise result. Test other pellets just the same, but make this one your primary choice until you find something better.
This was the fourth part of what would normally be a three-part test. I feel compelled to return to the range with a more powerful scope mounted on the gun and have another go at it. Maybe — just maybe, mind you — I’ll also take this rifle out to 100 yards. It will take a perfect day, but as I am planning to test other airguns at that range, I thought this one might be included.
by B.B. Pelletier
Shivashankar says this is his 4-year-old son with his dad’s Diana Model 23 on the boy’s first day at their club!
The FWB 300S is considered the gold standard of vintage target air rifles.
We’ll look at accuracy today, but this isn’t our last look at the 300S. You convinced me to take this rifle to the range and test it at 50 yards. I’ll do that, but I have to have a perfectly calm day for it. Kevin also convinced me to test weight-sorted pellets against pellets straight from the tin, so that’s how I’ll do the test. I want to use domed pellets at that distance, so today I’ll be looking for a good one that the rifle likes.
More 300S trivia
Mac sent a batch of photos to show some details that few people have ever seen. I’ll show a couple today and more in the next report.
Remember the Running Target rifle we talked about last time? Well Mac sent photos to show how the loading port differs from the one found on the standard 300S match rifle. The port is the same size, but FWB has rotated it to the right to make access for loading a little easier. I guess they expected a lot of right-handed RT shooters, or more likely they also built one in a left-hand version. Mac’s is the right-hand rifle.
The standard 300S loading port is centered on top of the spring tube, to be equally accessible from either side.
On the right-hand Running Target rifle, the loading port is rotated to the right for better access from that side.
All of today’s shooting was done from a rest at 10 meters. I attached the Gehmann color filter wheel to the rear aperture and used the yellow filter to sharpen the bulls. It seemed to work okay. Unless I were to use it for a lot longer, I really could not say that it adds anything. I don’t shoot a 10-meter rifle often enough to notice things like that.
Pellet head size is important when shooting a target rifle, and I shot pellets with heads of 4.50mm and 4.52mm, but none with a 4.51mm. Interestingly, the 4.50mm heads ranged from bad to good; so even when you have a single head size, you aren’t done looking for the right pellet.
Pellets that didn’t make the grade
I tried nine pellets in this test. Seven were wadcutters and two were domes. RWS Hobby pellets and Gamo Match were the two that didn’t cut it. Both shot so poorly that I didn’t waste any time with them. Oddly, in the test of the FWB 150 I did last year, RWS Hobbys were tied with H&N Finale Match Pistol pellets as the best ones. Go figure!
I shot two 5-shot groups each with the other 7 pellets. And with 6 of the 7 pellets, the second group was smaller than the first. That lends support to the notion that an airgun barrel needs to be seasoned before it will perform its best.
The following pellets did okay, and I would have continued to use them if I had nothing better. Each of them seemed to want to do better than they were doing, but I tried an extended test with one of them and it didn’t pan out.
The RWS R10 Match Pistol pellet came the closest to making the final cut. Maybe if I shot it more it might improve. But the best group of five I got measured 0.153 inches between centers.
I tried the Vogel match pellet that Scott Pilkington makes here in the U.S. It’s a great match pellet, but for some reason the 300S didn’t care for it that much. This is the pellet I shot four groups with, but the best of them measured 0.192 inches between centers. No dice!
JSB S100 Match pellets were another tease. The best group measured 0.113 inches between centers, but in the end it just wasn’t enough to make the cut. This was the only pellet I tried that had a head size of 4.52mm. All the others were 4.50mm. This pellet did very well in an Edge match rifle from AirForce, so I thought it might have a chance here, but no dice.
The one domed pellet that I thought might work but didn’t was the Air Arms Falcon pellet. The best group out of two was 0.167 inches between centers. It was a nice, round group; and because this isn’t a wadcutter, the group looks about half the size it really is. With domes, you have to make extra allowances for the skirt that tears through the target paper.
Three pellets showed great promise in the 300S, and one of them was superb. The JSB Exact RS was the best domed pellet, putting 5 shots into a beautiful round group that measured just 0.111 inches between centers. Because these groups are all so small, I’ve enlarged the photos for you to see them better. My dime is in the photo for reference. This is the pellet I will take out to 50 yards.
I tried both H&N Finale Match Pistol pellets and H&N Finale Match Rifle pellets in the 300S, and both turned in a wonderful performance. These are the pellets the gun likes best. The Finale Match Pistol pellets turned in a group that measured 0.117 inches between centers. It looked very good when I saw it, but one that’s even better was yet to come.
The best pellet of the day was the last one I shot — the H&N Finale Match Rifle pellet. Five of them went onto a group measuring 0.097 inches.
So we found out what we knew all along: the FWB 300S is an accurate target rifle. Just for fun, I checked back to the test of the FWB 150 and saw that the best two groups with that rifle measured 0.119 inches between centers, so I did a little better with this one. On any given day, I suppose either rifle would emerge the victor. But I like the firing behavior of the 300S a little better.
The next time you see this rifle, it will have fired those JSB Exact RS pellets at 50 yards. What a day that will be!
by B.B. Pelletier
Our favorite guest blogger, Vince, is at it again. Today, he shares his experience of testing a Chinese airgun.
If you’d like to write a guest post for this blog, please email us.
Now, take it away, Vince!
Ahhh… the way we were! The way some of us were, anyway. By “us,” I’m referring to those of us who first got into airguns (or came back to airguns) after being seduced by those irrascible Chinese. I’m going back about, oh, 10 years or so ago, when, waltzing through the internet, we would find all sorts of places selling “The Chinese Can Opener” or the “High-Power Military Training Air Rifle.” What a deal they were — my goodness, why on earth would ANYONE spend $100 or more on one of those high-falutin’ overpriced airguns when these $25 Chinese models were obviously just as good? And we knew they were just as good because that number said so!
You know, that number. The velocity number. Because that was the only thing that mattered! That one number told us the whole story!
Sooner or later, we discovered the inevitable — although for some (like, uh, me), it was certainly later than sooner. Eventually, the B3, B4-2 and Fast Deer airguns went by the wayside to be replaced by Gamos, RWSs, Cometas, Noricas, and then Spanish and German Beemans. Around this time, the Chinese started cranking up the quality, though, so their better products didn’t entirely leave our field of view. But the old carved-out-of-a-2×4-and-lubed-with-pig-fat models — along with all their broken seals, mainsprings and promises — were pretty much forgotten.
But man is a funny animal, and a collector (even a half-baked collector) often sees value in diversity as well as quality. And just as a man who collects Mustangs sort of really needs a 1974 Mustang II 4 cylinder automatic (as horrid a car as it was) in his collection, I began pining for some of those old, crude guns just because they were there.
So it was that I found myself fishing around for some of those old bottom-feeders…those poorly made, all wood-steel-and-leather guns that smelled like bacon grease when fired. Those guns that, frankly, I had virtually no interest in shooting, except to appreciate the better guns that came later. The subject of this report, the Industry Brand QB-51, is one of those fossils I dug up.
Industry Brand B-7 spring-piston rifle.
This .177-caliber breakbarrel air rifle was also called the Industry Brand B-7 and shouldn’t be confused with the BAM B-7. That gun was the old sporter-style sidelever that actually had a reputation for being sort of decent. No, the Industry Brand B-7 was one of those smoke-and-soot, machined with a dull file and worn-out drill bits and carved-with-a-hatchet examples of communism at its most typical. If you were lucky, it worked out of the box. If not, well, it simply didn’t. But luck shines upon me, and this one actually did.
The QB-51 was one of those novelty guns they used to put together by combining a low-buck action with some possibly less-than-useless useless bells and whistles. This one was apparently playing paratrooper with a folding wire stock, a total weight of under 6 lbs. and an overall length of only 35 inches. But it’s not a kid’s gun by any stretch — the pull length of 14 inches and a 28-lb. cocking force certainly attest to that.
Since the folding stock is obviously the most interesting aspect of this gun, let’s take a look at that first. It actually has two interesting features, the less obvious being an adjustable buttpad.
Buttpad is centered.
Buttpad adjusted down.
Is an adjustable buttpad on this cheap gun completely pointless? Actually it isn’t. It can be used to dial up a more comfortable shooting position. The gun does look awkward as all get out if the pad is moved too far off the normal position; but let’s face it, this pup isn’t winning any beauty contests if the judges are permitted to keep their eyes open.
The folding stock is perhaps less useful.
Folding stock extended.
The stock is folded flat against the side of the gun.
This is what it looks like from the side.
Some rifles with a folding stock can be handled as a pistol (sort of); that’s not really going to happen with this gun. All it does is make the rifle a bit shorter and easier to pack up for transport — if you could think of any reason you’d want to. But at least the rough cast folding/locking mechanism is stout enough.
The hinge is stout and tight!
Moving past that, we come to the pistol grip — and another gadget! The grip is hollow and has a sliding door at the bottom.
The grip has a secret compartment!
Presumably, you can put pellets in there. It would hold several hundred, even if getting them out one at a time might be a bit tricky. Again, we have an oddball feature that still isn’t quite useless.
On top of the gun, we can see the simple rear sight. If you were into mid-grade airguns 10-15 years ago, you might recognize it. This is pretty much a knock-off of the old Gamo sight that used to come on a variety of their breakbarrels. Frankly, they did well to copy it. It’s simple, largely devoid of free-play and pretty darned rugged.
The rear sight was kind of nice!
Finding it on this rifle was a pleasant surprise, and I was hoping to find a similar surprise as I moved rearward toward the trigger. I already knew that Industry Brand used a knock-off of the Gamo trigger in their QB-57, QB-88 and QB-25 models. When I saw that telltale safety tang in the triggerguard area, I got my hopes up. It says something about bottom-feeder Industry Brand triggers when you’re seriously looking forward to a Gamo trigger. But even those modest hopes were quickly dashed. This gun has a simple direct-sear and a crude sliding safety, both of which makes a 2004 Gamo Shadow feel like a Swiss watch.
As I move around the gun, it’s becoming obvious that this thing is based on the old Industry Brand 61 and 62 model actions, later known as the B-1 and B-2, respectively. I’ve had those. My B-1 had a horribly inaccurate barrel and probably a 12-lb. trigger. One B-2 had a soft trigger that quickly wore and went into the auto-fire mode, and the other B-2 bent its rear retaining pin because it couldn’t handle the spring pressure. As one might guess, I don’t get all excited by B-1/B-2 variants.
One giveaway is the breech pivot bolt.
The pivot bolt has only four places for the locking screw to engage. That often makes it difficult to adjust properly, for many times you want to stop somewhere in-between.
And the other is the smashed-leather breech seal.
The leather breech seal is as flat as a pancake.
Both are hallmarks of Industry Brand inferiority, and that breech bolt (with its four positive locking stops) frequently makes it impossible to properly tighten up the sideplay without making custom washers to go under the bolt head.
Oh well…let’s keep going. The front sight is basic enough.
Front sight is what you would expect.
Although I won’t be using it. I’ve learned from recent testing that I just can’t be consistent with open sights anymore — so I pretty much have to go to a scope. The problem is that the grooves milled into the receiver are ridiculously short. In trying to mount a scope, look at what I had to resort to.
The Daisy variable scope was cheap enough and worked well. Notice how close the rings have to be to fit the short dovetails!
The skinny scope mounts I used — moved as close together as possible — barely fit. The scope, by the way, is a cheap Daisy Powerline 3-9×32 (no AO), in which I had fudged the objective lens to eliminate parallax at 10 yards. Set up this way, the $35 scope works like a champ — and seems way too good for a rifle like this.
I do have some concerns about running a scope on this gun, however — Diana’s aren’t the only breakbarrels to have droop, and this one seemed to have joined that party. But there’s only one way to find out, so I’m off to test it. And, yes, this time I checked the stock screws first.
I’m shooting the gun with the same series of pellets I used last time — although, frankly, putting Crosman Premiers through this rifle seems rather silly.
I tried all these pellets in this gun.
No matter, same drill — 5 shots to get the barrel used to a pellet, then 5 on each through two separate bulls.
Much to my surprise, dialing in the Daisy scope wasn’t such a big deal, and soon I was landing pellets close enough for government work. Though the Daisy scope worked well enough, the Daisy Precision Max wadcutter pellets didn’t.
These groups came in at 0.66 inches and 0.82 inches; but come to think of it, maybe I’m being too hard on these pellets. Maybe this really is the best this gun can do!
Crosman Competition wadcutters do nothing to dispel that notion. At 0.78 inches and 1.40 inches, they’re making the Daisys look good.
At 1.28 inches and 1.52 inches, Crosman Hunting pellets (pointed) do even worse.
Even my cherished Crosman Premier hollowpoints are sucking canal water at 1.12 inches and 0.9 inches.
Of all the Crosman pellets, only the Premier Lites seems to consistently do under an inch — although 0.82 inches and 0.9 inches is nothing to squawk about.
Oddly enough, those new Gamo Match pellets I don’t like so much just about equalled the Crosman Premier Lites in this gun.
But at 0.95 inches and 0.88 inches, they still couldn’t match the Daisys. I had high hopes for the RWS Diabolo Basic pellets that seem to shoot so well in many low-power guns. I finally started to see some improvement.
At 0.57 inches for both groups, they were quite consistent; and now we’re starting to get into the range of acceptable performance for a cheap rifle.
But then we have the Beemans. Not the German Beemans from H&N. I’m referring to those imposter, Chinese-made Beeman wadcutter coated pellets. My very first group with them was typical for this rifle.
As you can see, the second group was a shocker. We went from 0.78 inches to 0.37 inches in one set. Something’s up. Let’s try this one more time.
My goodness! Stick a feather on my rump and call me a turkey — but this Chinese junk just put 5 pellets into virtually a 1/4-inch group.
Now, before anyone starts complaining — “That’s not fair! No other pellet got a third chance!” — let me explain something. The Beemans were absolutely the first pellets I shot, and during that time I was trying to come to grips with that yucky trigger. That’s why I think the first group was poor. Since the second group did so well, I shot the third group last after I had completed all other testing. So I think this third test was fair and that it really means something.
[Editor's note. This happens sometimes, and it's a reminder of the hold sensitivity issue and why things have to be done just right to see good results. I've seen what Vince is talking about. With some experience under your belt, you'll know when something deserves a second chance like this.]
But before we get too excited, let’s do a velocity check. Since the Chinese Beeman pellets were far and away the best, those were the only ones I tested. 10 shots came out like so: 396, 397, 388, 390, 380, 381, 381, 379, 381, 377.
We immediately notice three things: (1) The velocity stinks, especially for a gun with an almost 30-lb. cocking force. (2) The velocity seems to be on a downward trend. (3) The spread of 19 f.p.s. is significant, considering the fact that this thing is outgunned by a P17 pistol.
Where does that leave us?
Well, to begin with, this gun obviously has a decent barrel. Not sure how that happened, but happen it did. And if the barrel is good, the gun is good, right? Couple that with the fact that, against all odds, this example also seems to have a consistent lockup — and we seem to have a perfect diamond in the rough.
Yes – very rough. I could probably go through this gun and get the velocity up to 500-600 f.p.s. range, and some trigger smoothing and lubing would probably help as well. Even at that — will I ever want to shoot this thing just for fun? Really?
If I’m honest — not really. In fact, I have absolutely no reason IN THE WORLD to go through the trouble of tearing this thing apart and making it right.
Nope. No reason at all.
I’ll let y’all know how it turns out.
[Editor's note. Maybe I should have made this a Part 1. We'll see what Vince does. I don't want him to feel pressured.]
by B.B. Pelletier
I’m starting a report on a classic air pistol. It’s one that is so well designed that it has caused a stir in the firearms community. I’m looking at Smith & Wesson’s 586 revolver. The 586 exists in S&W’s line as a .357 Magnum revolver, along with its stainless cousin, the 686. The pellet gun also comes in both black and silver finishes, and the silver finish is named the 686, just like the firearm. Both guns are .177-caliber pellet guns with rifled barrels. No other calibers are available.
A barrel/shroud wrench still comes packed with each revolver, and these guns offered replacement barrels of different lengths at one time. I’m testing the gun with the 6-inch barrel, but a 4-inch barrel model is also available. Spare barrels are now available only on the used gun market.
This pellet gun is a true revolver, with a rotating metal clip that mimics the cylinder of a firearm. The clip is only a little longer than a pellet and sits at the front of what appears to be a full-sized cylinder. But when the crane swings out, only the clip comes out of the gun. It then lifts off the crane for loading. The gun comes with a second clip, and each clip holds 10 pellets. All clips are black, so they look out of place on the silver gun.
I’ve reviewed this gun before on this blog. Most recently, I looked at it in a 2-part report in 2008. But things have changed since I last tested this air pistol, and I wanted to update the information. If you’re serious about wanting a fine air pistol that’s affordable, this is one of the few to consider.
The biggest change to the gun I’m now testing is the finish that has gone from shiny to matte black. Pyramyd Air photos show the new finish very clearly; but if you weren’t aware of the change, you might miss it. I note that the 4-inch barrel model is currently shown on the website with the shiny finish. Maybe there are still some older guns in the system, because in the new Umarex catalog both guns have a matte finish. Edith is looking into this for us.
The gun comes with several accessories packed in the box. There are front sight blades, a spare circular clip, the barrel wrench and a bore-cleaning brush. The owner’s manual is clearly written and very detailed.
The gun comes with three front sight posts of different widths to suit your personal preferences. Heck — even Smith & Wesson doesn’t do that with their firearm revolvers! Each insert can be quickly installed with just a single screw. Different width front posts are meant to suit shooters who have eyes of different focusing ability. Generally speaking, you want the widest front post that still allows light to show on either side in the rear notch. That makes aiming at black bullseyes much easier.
The rear sight is adjustable in both directions. Surprisingly, no screwdriver is included with the gun. I say that because every S&W revolver I ever bought had a silver-handled screwdriver for this purpose. I felt no crisp detents on either adjustment, but the vertical screw does pause as it turns. The horizontal screw just turns smoothly, as far as I can tell.
The 586 is both single- and double-action with really great trigger-pulls in both modes. I’ll measure the trigger and comment more in Part 2, but you can rest assured this revolver’s trigger is one of the best things about the whole gun.
The .177-caliber pellet gun weighs 45.4 ozs. The .357 Magnum revolver of the same barrel length weighs 46.3 ounces. That’s pretty close! I’ve owned a 686 .357 Mag and can tell you this gun feels like the real deal!
Where does the CO2 go?
There’s only one place for the CO2 cartridge to go, and that’s inside the grip. Flip down the bottom of the grip that also serves as the CO2 cartridge piercing lever. That gives you access to the underside of the right grip panel, which then flips off with ease. Inside is a standard CO2 cartridge adjustment mechanism that allows cartridges of slightly different lengths to seal properly.
The revolver comes packed in a nice hard case with foam lining. Each accessory has cutouts at the right spot, so nothing slides around. It’s the same way firearms come these days.
I guess I’m attracted to this revolver, because this will be the third time I’ve tested it for you. It’s a classic that has a great trigger, many useful accessories and, hopefully, the accuracy we have come to expect from Smith & Wesson. Though they don’t actually make the gun, they do license their brand on it and are very interested that it is perceived as a good handgun. I think it is, and I hope to show that to you in this test.
by B.B. Pelletier
Quackenbush .308 is handsome even in this lowest-grade version.
Today’s report will be quite different from the norm. This is Part 2, which is normally where I test velocity. I did that, and you’ll see it in today’s report — but you’ll also see some targets, because I tested accuracy, too.
When I test a smallbore pellet gun, I know at the start how the gun should perform, more or less. Yes, there are some surprises; and yes, I do make some mistakes — but a lot of what happens can be predicted pretty accurately. But not a big bore!
With a big bore airgun, I’m almost starting from scratch. Sometimes, I will have tested something similar and can use that experience as a starting point, and there’s some of that in today’s report; but this .308 rifle is unlike any other big bore air rifle I’ve ever tested. There are more .308 lead bullet designs and bullet molds available than there are .177 pellet types on the market. Out of all that, I have to select some designs that make sense.
This is where my firearms experience comes in handy, and this is the reason I often run reports on firearms in this blog: learning the intricacies of this Quackenbush rifle is exactly like figuring out how a new black powder rifle operates. And I don’t mean some ultra-modern, bolt-action black powder rifle that uses replica powders in pellet form, either. I mean a real black powder rifle made by hand and has to be figured out as you go.
So, how do you start testing a gun when you don’t know much about it? Well, you start with what you do know and go from there.
I know that other Quackenbush Long Action Outlaw guns operate at pressures above 3,000 psi, so I’ll start with a higher fill pressure. I know that this rifle will be in the 200-250 foot-pound range with bullets it can stabilize, so I’ll select them first. I know that by reading what others have written about their .308 rifles.
I also know that Quackenbush rifles have to break in. They do get faster with use. So, I’ll look for that.
Furthermore, since this is a big bore air rifle operating at a very high level of performance, it’s going to use a lot of air. I know how much air the Korean guns like the .50-caliber Dragon Claw use, and I know that this rifle is going to use even more. So, even an 88 cubic-foot carbon fiber air tank is going to get drained in a hurry.
I cast bullets for many of my firearms, and I also happen to own a bullet mold for a nice spitzer (pointed) lead bullet that was designed for the M1 Carbine. It casts at around 130 grains, which is an ideal weight for this rifle, because the expected velocity (derived from the known power that has been published by other .308 owners) will be 850-950 f.p.s. on the first shot. I calculate this velocity range by taking the expected power (say 225 foot-pounds) and running it through the Pyramyd Air velocity calculator (use the second formula on the page to do this).
The issue here is bullet stability. These bullets are stabilized primarily by the spin imparted by the rifling in the gun. The longer a bullet becomes, the faster it must spin in order to stabilize. Since you cannot change the twist rate of the barrel, you have to drive the bullet faster to stabilize it. Sometimes, though, you’ll get away with shooting targets that aren’t too far away with a longer bullet. The bullet will be semi-stable for the first 40-50 yards or so. It all depends on the bullet’s length.
The bullets I shot are like the one at the center of this photo. At the right is that same bullet with the lubricant wiped off. At the left is a 170-grain lead bullet that’s normally too heavy for this rifle. However, for close work, it might work okay. That bullet normally takes a copper gas check, but it can be shot without one.
That velocity will give a fairly flat trajectory and stability to the 130-grain bullet as far as the rifle can be accurately shot — which is about 200 yards. But consider this: this bullet is just one of over 200 different lead bullets that are appropriate for this rifle! If you really want to experiment and push the envelope, that number grows to over 500! Nothing guarantees that this will be the one right bullet. It’s just the first one I tested.
Before I went to the range, I mounted a scope on the rifle. I encountered problems right away because of how far the Weaver bases are set apart on the rifle’s action. They are so far apart that I cannot mount the leapers long eye relief scope I had planned to use, because the ring separation exceeds the scope’s tube length. This is where it gets dicey because of the scopes that were available; and the Weaver rings I had that were not committed to other tests and guns. I ended up with a set of high rings and an Osprey 2.5-10×40 scope that I don’t care for. More on that, later.
So, I get to the range and the day is pretty good. The wind is fairly calm, with just a few breezes I can wait out. Besides, I’m shooting a .308 130-grain bullet at 50 yards. The wind doesn’t affect it nearly as much as it would a pellet!
The gun’s first fill is a guess. I know my .458 Outlaw likes a 3,500 psi fill, so I go with 3,600 psi for this one. I’m looking for a couple things. First, how fast does the first shot go? Second, how fast do shots two through whatever go? That’s right — I don’t even know how many powerful shots I’m going to get from this rifle. If it were a 9mm Korean gun, that number would be 5-7. But a Quackenbush .308 is more powerful and uses a lot more air. My .458 gets two good shots per fill, so there’s a very good chance this one will, too.
Before I left the house, I oiled the striker (hammer) with high-tech gun oil. I oiled it again at the range. I know that all big bore guns need to break in to shoot their best. Then, I filled the rifle to 3,600 psi and started shooting:
The first few shots were over the chronograph. Then, I commenced shooting for accuracy at 50 yards. You can see how high the scope sits above the receiver.
Okay, those are the first four shots. If I’m looking for good groups at 50 yards with this bullet, only the first two shots look good. If I’m demonstrating the rifle to a bunch of Boy Scouts, I can probably continue shooting for another couple shots. Do you see what I’m doing? I’m calculating things based on what kind of shooting I expect to do.
And shot one generates 212.06 foot-pounds of muzzle energy. Shot two makes 192.26 foot-pounds.
I also noted that when I went to fill the reservoir again, the gun still had about 1,900 psi inside. Four shots used up 1,700 psi, or about 425 psi per shot. The Korean big bores use around 200 psi per shot, so that gives you a good idea of how they compare to a Quackenbush Long Action.
Next, I sighted-in the rifle. Because the Quackenbush Long Action does not allow the bolt to be removed easily at the range, I used a target paper that’s two feet by four feet. The point of aim is close to the center of the paper. That gives me a good chance of striking somewhere on the paper at 50 yards. If this were a smallbore airgun, I would have started at 10 feet, as I explain in my article about sighting in a scope; but you can’t do that with a gun this powerful unless you own a lot of private land. I’m on a club-run rifle range, and I have to obey their regulations. I’m hoping to get on paper without boresighting. I do own a boresight device, but it has only bore spuds that go up to .22 caliber, so it wouldn’t work in a .308.
I’m in luck, because the first shot hits the paper…about two feet below my aim point. Well, that isn’t as lucky as you might think. Remember the Osprey scope I mentioned earlier? Well, it has 1/8 MOA (minute of angle) adjustments. At 50 yards, every click will move the strike of the round about one-sixteenth of an inch! For two feet, I’ll have to move the elevation knob up 16 x 12 x two, which is 384 clicks! There probably aren’t that many clicks in this scope, plus I don’t know how far up it already is. I have a droop problem!
I’ll replace this scope and mounts for the next test, which means I’ll have to sight-in and do this all over again. But today is not lost. I can still continue to test the gun. I adjust the scope up so the round lands about 14 inches below the aim point, and that’s how I will test the gun today. It’s simple enough to staple two targets to the backer in line with one another, so I can aim at the top one and hit the lower one. Now, we can see how this rifle shoots with this bullet.
The only problem is — all I have are bullets that have been sized and lubricated. I know that Quackenbush big bores seem to do best with dry lead bullets, or at least that’s been my experience up until now, but I’ll use the bullets I have on hand. I will have to cast some more bullets and not lubricate them for the next test.
Shot one went about 14 inches below the point of aim, as mentioned already. Shot two dropped another several inches, but I compensated for it by using the tip of the bottom fat vertical duplex reticle line as a different aim point. So, I’m able to get a fair grouping of bullets, though it’s nothing I am satisfied with, yet. I’m able to shoot six bullets into a group measuring 1.6 inches by shooting just two shots per fill and using the two aim points. After shot two, the gun’s remaining pressure is about 2,700 psi, so the first two shots use about 900 psi — which works out to 450 psi per shot. Do you see how this stuff works?
Two bullets in the hole on the left, and you can see the rest. Three of them were first shots after a fill, and three were second shots. This group measures 1.6 inches between centers.
I then moved over to another set of targets and tried something different. I tried refilling after the first shot — so every shot would be going the same speed and I could use the same aim point. This time, four of the five shots grouped into 0.982 inches, but the fifth shot opened it to 1.767 inches. It looked like it was going to be better, but once again, no cigar.
There are three bullets in the large hole on the left. Shot four (top) opened the group to just under one inch, but the fifth shot opened the group to almost 1.75 inches.
After shooting at two different targets, I lubricated the striker again and chronographed the gun. This time, I tried to fill the reservoir higher than 3,600 psi, but my carbon fiber tank had already dropped to 3,600 psi. I had to stick with that as the highest fill pressure.
As you can see by comparing this second string to the first one, my rifle seems to be performing at the same level, more or less. That does not tell me whether 3,600 psi is the highest operating pressure or not, but it’s a good indication that the rifle either needs a lot more shots through it or it’s already broken in. I’ll have to get my carbon fiber tank refilled before I can conduct another test at a higher fill pressure.
And just for continuity, the first shot generated 217.04 foot-pounds. Shot two generated 193.67 foot-pounds.
Where to next?
If you’re as curious as I am, these results open up a lot of possibilities. For starters I want to test the gun at a higher fill pressure. I also want to shoot dry bullets, but I think I need to clean and dry the bore before I do. I can’t clean the lubricated bullets well enough to consider them dry, so I have to cast another batch.
I definitely have to mount a different scope in lower rings, and I have to be prepared to elevate the rear mount if the rifle turns out to be a drooper. All I know at this point is that I had the scope adjusted very high, which very well could have lead to the groups being as large as they were.
I have a feeling that this rifle will shoot groups smaller than one inch once I learn its secrets.