Archive for December 2011
Pellet velocity versus accuracy test: Part 11
by B.B. Pelletier
Announcement: Dammion Howard is this week’s winner of Pyramyd Air’s Christmas Big Shot on their facebook page. He’ll receive a $50 Pyramyd Air gift card plus another $50 in goodies!
Dammion Howard (left) shows off some new airguns he found under the tree this year!
Part 1
Part 2
Part 3
Part 4
Part 5
Part 6
Part 7
Part 8
Part 9
Part 10
Happy New Year from Tom & Edith!
One nice thing about watching a TV program is that it only takes an hour or less to view. You have no sense of the man-weeks of work that go into a short production on screen. Sometimes, the same thing happens in the world of airgun blogs.
I won’t say I’ve been dreading today’s report; but from past experience adjusting the HOTS on the Whiscombe rifle, I knew it might take longer than anyone could imagine to get a good result. It’s easy to say, “Adjust the HOTS for optimum performance with a certain pellet.” Actually doing it is where you discover if it’ll be easy or hard. The report I have for you today was very hard.
I allotted several hours to the actual testing and adjusting that would have to be done. And with my past experience with the Whiscombe, I knew shortcuts the average shooter wouldn’t think of. Let me lay the groundwork so you understand what’s happening in this process
The HOTS
The Whiscombe harmonic optimized tuning system (HOTS) consists of a weight that can be adjusted in or out along the axis of the bore. A jacket around the barrel is threaded to receive this weight. The threads on the weight are very fine, and one turn of the weight moves it a millimeter in either direction. One complete turn of the weight constitutes 1mm movement of the weight.
Besides the weight, there are two other metal parts. One is a short collar that locks the weight in position after it’s been adjusted, and the other is a much longer cover that encloses the entire HOTS from sight. This longer cap doesn’t need to be removed from the weight to make adjustments, just provide access room for the special wrench that moves the weight.
Here you see the HOTS mechanism. The threaded weight is turned in or out of the barrel jacket by the wrench. Once the weight is where you want it, lock it down with the knurled collar on the barrel jacket. Then, install the long cap, and the job is done.
Where to start?
The problem is always the same: Where do you start adjusting the weight? The simplest way is to start right where you are — with the HOTS in the last position it was set. Shoot a group at that setting and go from there. I had that data, of course, from the earlier part of this test, so that’s where I began. Because the last transfer port is still installed in the rifle, the Beeman Devastator pellet still develops about 772 f.p.s.
When I shot a group at this velocity in the earlier test, 10 shots went into a group measuring 1.073 inches between centers. I was looking for a group somewhere near that size this time, too. It might be a little smaller or larger; but if it was a quarter-inch group, there was a problem with the results of the last test. The same care was taken with each shot; to do any less would have skewed the results or made them unreliable at the very least.
The first group shot in this test, shot with the same HOTS setting, measured 0.953 inches between centers. That’s 0.12 inches smaller than the group from the last test. I would call that in the same ballpark and therefore a confirmation that the last test was sound.
Ten Beeman Devastators at 25 yards went into this 0.953-inch group with the original HOTS setting. It’s close to what the gun did in the last test on the same setting.
Adjusting the HOTS
Whiscombe says that there will be several sweet spots throughout a one-inch movement of the weight, which is approximately 25 full turns. He also says that one spot will be better than the others, and that’s the one to look for. He just doesn’t tell you how to find it, other than by adjusting the weight one turn at a time. But my experience told me that the sweet spot was probably not where the weight was at this time, so I turned it in (toward the receiver of the gun) four full turns and shot a second group. This is where my experience with the Whiscombe was supposed to pay off.
I wasn’t going to waste my time shooting 10 shots if the first 5 were spread out. Why bother? I wanted a tight group, and if inside 3-4 shots — or even 2, on one occasion — there was already a large separation, it was no use going further. I turned the weight in 4 full turns and shot another group. This group teased me with the first 5 shots in less than a quarter-inch, but the final 5 expanded that to 0.977 inches. Can’t be certain because of measurement errors, but no improvement at all.
At 0.977 inches, this group is slightly larger than the original setting. Obviously, the HOTS isn’t adjusted at this spot.
Next, I tried the weight 5 turns in from the start point. The group was worse. I backed out to 3 turns in and got about the same size group as with 4 turns in.
At this point, I experimented with some subtle adjustments on a half and then a quarter turn. At 3.5 turns in, I got a group that was slightly smaller than the one at 4 turns, but it had one called flyer. I tried another quarter turn in and got 4 shots in a group measuring 0.998 inches between centers. Obviously, I wasn’t going the right way.
No sense finishing this group. Four shots are already grouping 0.998 inches.
Okay, this wasn’t working. I adjusted the weight out in the other direction 9 full turns past the initial setting and shot another group of 10. This time there was some success, as the group measured 0.794 inches between centers. I wanted to call that the end of the test; but looking at the group, I knew it wasn’t enough of a difference to impress anyone. Even though it does show improvement over the baseline group, I would like to show a larger change since one of the Devastator groups in the earlier tests measured 0.616 inches. This group was too much larger than that. The gun should be able to do better if harmonics and not velocity was the main driving force behind accuracy.
This group is better than the baseline group, but it’s not as good as some groups that were fired in the big test. It measures 0.794 inches between centers.
By this time, I’d fired 49 shots in about 90 minutes. The test work had lasted much longer than expected, and I had to quit for the day.
A happy accident
The next morning, I was back at the bench and trying to complete the work. I figured I would adjust the weight out from the initial setting by a certain amount but as I tried to do that a happy accident happened. The front cover got stuck together with the weight; and by the time I noticed it, I’d already adjusted it 15-20 turns. Except, I had no way of knowing how many turns it was. I had to start all over, and this time from a random place that bore no known relation to the initial start point. Not that it mattered, except I didn’t want to waste all of the work from the day before.
I adjusted the weight at a point that looked to be well away from the initial setting. Then, I shot a group as a baseline. Or I should say I began to shoot a group. After 3 shots, I had a spread of 1.153 inches between centers — the largest spread of the entire test to this point. No sense finishing that one!
Past experience has shown that the sweet spots are often a couple turns in either direction. I guessed and turned the weight back in three turns from the starting point. And that was when it happened. The clouds rolled back, the angles sang and the rifle grouped like I knew it could. Ten shots went into 0.523 inches. That’s not only the best group of this little experiment with the HOTS, it also beats every group fired with the rifle during the main test conducted earlier.
This group of 10 was shot on the second day, with 3 turns in from the start point. It measures 0.523 inches and proves that the Beeman Devastator can shoot accurately at 772 f.p.s.
The results
With this kind of data in hand, I can say with some confidence that harmonics and not velocity is the main driver in how accurate a spring gun can be. I say this because the worst group shot during the velocity test was adjusted harmonically into the best group of the test with this pellet. There’s no chance in this group — it’s clearly much better than it was in the beginning.
Could the rifle shoot this pellet even better? Maybe. But it isn’t necessary to prove the point we were trying to prove.
Next, I want to adjust the rifle for Beeman Kodiaks at a higher velocity and test pellets straight from the tin against pellets that are sorted by weight. Today’s report should give everyone the confidence that, if a difference in accuracy is noted, it will be because of the pellets and not the gun.
Mayhem .45 Sport Tactical air pistol: Part 1
by B.B. Pelletier
The Mayhem .45 Sport Tactical air pistol is a big, heavy airgun.
If you liked the Dan Wesson revolver we looked at a couple weeks ago, here’s another realistic airgun for you — the Mayhem .45 Sport Tactical air pistol. This one is a semiautomatic pistol style, and the owner’s manual says that it fires semiautomatically. Without a 12-gram CO2 cartridge installed, all I could feel was a double-action-only trigger-pull, because every pull of the trigger was obviously also cocking the internal striker. So I installed a cartridge to see if it really is semiautomatic once charged.
Not a semiautomatic
Indeed, this is not a semiautomatic! When you pull or squeeze the trigger, you’re also retracting the internal striker against a powerful spring. A true semiautomatic would cock this striker spring for you by the action of firing. In a firearm, the moving slide would push the external hammer back until the sear caught it and then all you would have to do is squeeze the trigger a little each time to release the sear. That is the definition of semiautomatic. The exposed hammer you see on the gun is a solid cast piece that doesn’t move, so the real striker (the correct name given to a weight that is internal and doesn’t pivot on an axis, but moves straight back and forth to impact the end of the valve stem) is inside the frame of the gun and hidden from view.
Some people insist that double-action-only applies to just revolvers, but that is incorrect. Glock sells only firearm pistols, but they label their triggers correctly as double-action-only. The Mayhem trigger is also DAO.
General impression
The Mayhem is very large and heavy. The grip feels wide — like the grip on a double-stack firearm pistol in which the cartridges in the magazine are offset to accommodate twice as many in the same magazine height.
The entire exterior of the pistol is metal except for the grip. That’s where the weight of 2.29 lbs. comes from.
The sights are the fiberoptic type that I usually criticize for their lack of precision, but this is a BB pistol and probably capable of shooting to the same precision as the sights can control. So, in this case, the sights match the capability of the gun very well. There are no adjustments for these sights. The front is a red tube that is largely unprotected from impact and the rear is a curved green tube that appears as two green dots.
The entire top of the pistol is a stylized Weaver rail that Pyramyd Air calls an optics rail. Under the muzzle, there’s also a short Picatinny rail for accessories like tactical flashlights. Weaver bases will attach to Picatinny rails, but not vice-versa.
Looking down on the top of the pistol, we see the stylistic “Weaver” sight rail that extends the length of the gun. It should accommodate standard Weaver bases, but it has non-typical scalloped notches instead of the usual square Weaver notches.
Underneath the slide at muzzle, there’s a short Picatinny rail for tactical flashlights and lasers.
The whole plastic grip panel pulls back to expose the CO2 cartridge housing. Loading is quick and easy and the screw that tensions the CO2 cartridge does not show when the grip is forward.
The grip pulls back to expose the CO2 receptacle. The BB magazine is a metal stick-style.
The 19-shot BB magazine is a stick-type located in the front of the grip. It’s made of metal and better-made than 90 percent of the stick magazines I see in similar airguns. The spring-loaded follower pulls down and locks at the bottom so you can load the magazine with one hand. There’s a wide opening for loading the BBs. When you’re finished, push the base of the follower that protrudes through the bottom of the magazine, and it’ll unlock and spring forward to tension the BBs.
The slide doesn’t move on this gun, nor is there any blowback sensation. The trigger stacks toward the end of the pull, allowing you to control the gun for more precision. It isn’t as easy to control as a gun with a single-stage trigger, but you can learn to control this kind of trigger pretty quickly. I imagine a gun like this will be chiefly used for plinking at soda cans and targets of equal size, though I do plan to test it on bullseye targets.
Power
The power is rated at 430 f.p.s. Since this is a steel BB gun, there can be no confusion about what that means. Only steel BBs will be used in the gun, so any that I try should go approximately that fast.
Airsoft heritage
This is another air pistol that made the transition from airsoft. You can see that in several places, starting with the threaded muzzle that’s obviously meant for a silencer. A second clue are multiple references made in the owner’s manual, where the instructions refer to this as a “soft air” pistol.
There’s nothing wrong with transitioning from an airsoft gun, We saw that in the Dan Wesson revolver and liked it very much. But this pistol must stand on its own merit, so it’s going to be treated the same as all other BB pistols. As nice as it feels, I hope it does well!
Daisy Powerline model 35 multi-pump air rifle: Part 2
by B.B. Pelletier
Daisy’s new model 35 multi-pump air rifle is designed for youth. It’s a smoothbore with several interesting features.
Today, we’ll look at the velocity of the Daisy Powerline model 35 multi-pump air rifle. You’ll remember from Part 1 that this is a smoothbore, and as such we’re going to be testing the accuracy with diabolo pellets. One reader asked me to test the velocity of the gun with round lead balls, so I did that, as well. There’s a lot to test, so let’s get to it.
Number of pumps
A multi-pump lets the shooter select the number of pumps for every shot — up to the maximum recommended number. In this case, that’s 10 pumps. I decided to test the model 35 on 5 and 10 pumps, just to simplify the test and to bound the amount of work to be done. Five pumps takes us to the place where the gun is shooting fast, but also where each successive pump provides diminishing returns. Ten pumps takes us all the way as high as the gun is recommended to go.
Crosman Premier lites
The 7.9-grain Crosman Premier pellet is a good choice for this gun if weight is the criteria. Because the model 35 is a pneumatic, this pellet won’t suffer like it would in a spring-piston gun of the same approximate power.
Five pumps
On five pumps, the velocity averaged 478 f.p.s. and ranged from 472 to 481 f.p.s. That gives us an average muzzle energy of 4.01 foot-pounds. This velocity should be okay for target shooting at 10 yards; but if I were shooting farther than 15 yards, I would probably pump it more.
Ten pumps
The model 35 is rated to develop 605 f.p.s. with pellets, but of course that would be with the lightest ones. I expected to see 550 f.p.s. with these 7.9-grain Premiers. They actually averaged 565 f.p.s. and ranged from 559 to 570 f.p.s. That’s a muzzle energy of 5.6 foot-pounds. I would have to say the gun meets my expectations when it comes to power.
Loading difficulties
I mentioned this in Part 1, and I’ll reinforce that now. This gun is very tricky to load with pellets. You must watch the large hole at the back of the short loading trough that’s there for BBs, or you’ll get a pellet stuck in it. I find it best to point the muzzle straight down and let the pellet tip over the edge of the receiver, where the nose will fall into the breech if you’re fortunate.
RWS Hobbys
Next to be tested were the 7-grain RWS Hobby pellets. You might think that these would be a lot faster because they’re almost a full grain lighter than the Premiers; but in a pneumatic gun, velocities don’t increase that fast.
Five pumps
Five pumps gave an average 495 f.p.s., or just 17 f.p.s. more than the Premier did at the same number of pumps. The range went from 492 to 503 f.p.s. The average muzzle energy was 3.81 foot-pounds.
Ten pumps
On the full 10 pumps, I expected to see the Hobby pellet approach 600 f.p.s., but it did not go quite that far. The average was 577 f.p.s., and the velocity ranged from 567 to a high of 586 f.p.s. At the average velocity, the muzzle energy was 5.18 foot-pounds.
BBs were next
Next up were steel BBs. I had to shoot either BBs or pellets. If there’s even a single BB in the gun’s internal reservoir, the magnetic bolt tip would attract it. I counted the BBs as I loaded the gun, because I didn’t want to have excess BBs remaining after this part of the test. Of course, I used Daisy zinc-plated BBs because this is a Daisy gun.
Five pumps
On 5 pumps, the BBs averaged 517 f.p.s. They ranged from a low of 505 to a high of 529 f.p.s. The average muzzle energy was 3.03 foot-pounds.
Ten pumps
Ten pumps bumped the average velocity to 616 f.p.s. — breaking the 600 f.p.s. level for the first time in the test. The velocity ranged from a low of 612 to a high of 619 f.p.s., so BBs were more stable than pellets in this gun. You don’t often see that. The muzzle energy was 4.3 foot-pounds.
Trigger-pull
The trigger-pull was noticeable throughout this test because it’s so heavy in relation to the overall weight of the gun. When a 9-lb. rifle has a 5-lb. trigger-pull, it seems right. On the other hand, when a 3-lb. gun, like this model 35, has a trigger that breaks at just over 6 lbs., it’s too much. It’s a single-stage and fairly free from creep, but the sheer weight of the pull is daunting. I think it’ll affect me during the accuracy test.
Round lead balls
I tried shooting some round lead balls in the gun because a reader asked me to. Since I will also shoot them for accuracy, I selected the largest lead balls in this caliber. Beeman Perfect Rounds, which were made by H&N and are identical to the H&N Rundkugel were the ones I chose. They measure 0.176-0.177 inches in diameter and weigh 8.3 grains.
Five pumps
On 5 pumps, these balls averaged 414 f.p.s. and ranged from a low of 396 to a high of 434 f.p.s. At that speed, they generate 3.16 foot-pounds.
Ten pumps
On 10 pumps, they average 504 f.p.s. and range from 480 to 522 f.p.s. They produce an average of 4.68 foot-pounds. With such a large velocity spread, I don’t look for great accuracy — especially at longer distances.
Evaluation so far
To this point, the model 35 is proving to be an interesting little pneumatic. The upcoming accuracy test of a smoothbore airgun is what I’m really waiting to see. Feeding with BBs was 100 percent positive, but with pellets it was difficult to load the gun. The lead balls loaded easily enough because they have no sharp shoulders like the pellets to grab things and turn them around. After all — they are balls — so who knows where the front is?
The trigger is heavy, but the sights are crisp. I’m looking forward to seeing what this little gun can do.
I will say this. The model 35 is very quiet! It has a No. 2 noise rating on Pyramyd Air’s site, and it deserves one. Only a Red Ryder would be reliably quieter.
Learning to shoot with open sights: Part 1
by B.B. Pelletier
Edith has been after me to write this report for over a year. I’ve been researching it and believe I can do it some justice, but this is a large topic. And it’s a fundamental one — like learning to shoot a handgun one-handed.
I’m going to make the case that the scope sight has destroyed the potential of more shooters than anything else. Not that scopes don’t work, but that they work too well. It’s my opinion that every shooter who is able (and that’s a lot more people than are willing to admit it) should first learn to shoot with open sights; because in doing so, they learn the fundamentals of breathing, trigger control, follow-through and perhaps many other basic components of accuracy as well.
History
There are several ways to go about this, and I’m going to present it in sort of a chronological sequence. The first guns had no sights at all, but that was okay, because they also were not at all accurate. Trying to aim one of them was almost a lost cause. I’m referring to the early hand cannons.
I see these guns coming to auction on Gun Broker from time to time, and the dealers sometimes list them as “target guns.” What a joke! These guns have wide, flared cannon-type muzzles, no sights and are the antithesis of a target gun. I think people list them that way because they have no notion of how a gun works, and the words they choose are for effect, only.
The first sights were nothing but reference points on the muzzles of guns. Sometimes, it was a raised bump at the top of the muzzle, and other times it was a groove or notch — just something the shooter could refer to when aiming the piece. The bead on a shotgun barrel is very similar to this kind of sight; and for the accuracy potential of the guns that had them, they were sufficient.
The simple bead is all the sight a modern shotgun gets. In essence, a shotgun is much like a musket of old.
The Kentucky rifle ushered in a new type of sight that, while not exactly new on the Kentucky, was certainly made famous by association with it. I’m referring to the low front blade that stood one-eighth inch tall or less and the wide rear vee that was equally low. These sights are so vestigial that they always look worn out to me, yet they’re capable of remarkable accuracy.
By the way, the term “Kentucky” is back in vogue for the types of American long rifles made from 1730 and afterwards — they have long barrels of relatively small caliber. Revisionist historians have tried to shove the title “Pennsylvania” down the throats of shooters and collectors for the past 60 years because most famous of these rifles were made in that region and not in Kentucky, which is just where they were carried and used. The term Kentucky rifle was originally used in Daniel Boone’s time because he explored the Kentucky region and both he and those who went with him carried this style of rifle. It was further popularized in a song during the War of 1812; and although it referred to a group of men in that song, rather than to their firearms, the name stuck.
The fine front sight blade on an early Kentucky rifle is so low that it appears to be worn out. It gave a fine aiming reference to good eyes.
An early Kentucky rear sight is a wide and shallow vee.
The early sights on a Kentucky rifle were low and fine. They gave a very small, sharp sight picture that resulted in extreme precision when good eyes were used.
Most shooters who see these primitive sights today think they’re not capable of accuracy, but history is full of anecdotes that prove otherwise. One of the more famous stories is the shot made by Daniel Boone during an Indian attack, when Boone shot a sniper in the forehead at a measured distance of more than 200 yards. It was a first-shot kill, and was apparently not considered to be that special, given the remarks that were made at the time.
A shooter with good eyes could “draw a bead” using as much or little of the front sight as he chose. Once a person became familiar with his rifle, sighting this way became second nature.
Paper targets found in the possibles bags of shooters prove these old rifles with their simple sights could often group their shots in one inch and less at 100 yards, though 60 yards was far more often the distance for a marksmanship contest. Because wood planks were the preferred targets of the 1700s through the 1860s, not too many original paper targets survive, though the older guns were often still being shot when paper targets came into widespread use after the American Civil War.
Kentucky windage
The term Kentucky windage stems from another special way the earliest type of sight was used. While the sights were often mounted on dovetails that could be moved left and right, it was much easier for the shooter to simply use a sight picture that compensated for the necessary windage. In other words, hold the rifle so the front sight appeared at different places on the rear vee. Since the need for windage changes with both the distance to the target and the wind, this is a very flexible way of doing it. The very fact that the term is “Kentucky” windage proves, yet again, that the popular name for the rifle was Kentucky and not Pennsylvania.
By holding the front sight to one side of the vee in the rear, the shooter controlled how far to one side the bullet went. This is called Kentucky windage.
Not made today
You’re not likely to see this early style of rifle sight today. The problem is that when Kentucky rifles are made new today, the makers almost never select the early primitive sights described here. Instead, they either use sights that are appropriate to rifles made at the end of the black powder era or they use sights that are even more modern, in the belief that they’re better and more appreciated by the customer. Perhaps they are, but only because the customer has little or no experience with the early, very primitive Kentucky sights.
Sights mature
The sights most often seen on guns we call Kentucky rifles are not the early Kentucky style, but the later plains rifle sights that most muzzleloading rifles had from about 1820 onward. The front blade is taller than the traditional Kentucky blade described above, and the rear sight is taller with a more of a buckhorn design. Many of these later sights are adjustable, or they have features like folding express leaves of different heights.
The American Civil War did much to mature open sights, but not the sights on the military guns. However, the civilian models evolved quite a lot — starting around this time; by 1875, they were as advanced as they would get for another 75 years.
After the American Civil War, front sights grew in height and gained some form like this one from 1867.
This post-1860 rear sight has two leaves for two different distances. Notice that the shallow vee has become a notch.
They also started to branch off into sporting sights and target sights. The sporting sights became more like the style that had been called target sights before 1860, while the target sights evolved into units capable of the greatest precision.
The driving force for this rapid advancement was a worldwide interest in target shooting. It exploded onto the American scene when, in 1874, the U.S. decided to accept the challenge of the Irish National team for the championship of the world. No one expected the Americans to make more than an honorable showing; but when the smoke cleared on the Creedmore rifle range, they were the new world champions!
The target sights they used were one of the special advantages they brought to the field, having increased in precision half an order of magnitude just for this match.
In the next report, I’ll show you how the sporting open sights continued to evolve plus what happened to the target sights.
B.B.’s bag of tricks for twitchy airguns
by B.B. Pelletier
Before we begin, I’d like to share my Christmas with you. I didn’t get any airguns or firearms this year, but I did get a wonderful reloading tool. It’s a Pope-style capper and decapper for priming and depriming cartridge cases while at the rifle range. You do that with the old-fashioned target rifles like my Ballard, and I’ve wanted to do it for a long time. But until I actually saw the tool and held it in my hands, I had no appreciation of how neat and handy it was!
This loading tool is a Pope-style capper/decapper. It’s cartridge-specific and very handy to use. This one is for .38-55.
This will help me shoot the Ballard in the style it was shot when the gun was new. It also eliminates a lot of extra clutter needed to load the rifle. I’m still waiting for a custom bullet mold that I’ll need before I start shooting the Ballard again (it’s on the way but didn’t arrive in time for Christmas).
Edith, however, did get a gun from Santa. It’s a full-sized Glock made of milk chocolate! It came in a pistol case and really looks the part. Edith calls it death by chocolate!
A chocolate Glock that came in a hard pistol case. Edith loves it! She also got a chocolate hand grenade. Death by chocolate takes on a whole new meaning.
I hope all of you will share your gun-related gifts with us in the comments. It’s like being invited to your homes for Christmas. Now, let’s get into today’s report.
As much testing as I do, I run into lots of airguns that are difficult to shoot. Spring-piston airguns are the hardest to shoot as a class of gun. The preponderance of them are breakbarrels; and of those, the more powerful ones are harder to shoot accurately than any other kind of rifle — firearm or air-powered. Naturally, I always begin by using the artillery hold, but often something more is needed to get the rifle shooting its best. Let me show you what I do when this happens.
Adjustments to the artillery hold
I’m assuming that ya’ll know about the artillery hold; for those who don’t, here’s a brief article and video that explain it.
Most of what I’m about to say is also in the video. If the normal artillery hold isn’t working, try resting the rifle on the backs of your fingers. This provides a narrower fulcrum and often removes some of the randomness you get from holding the rifle on the flat of your palm.
Whether the rifle is resting on my palm or the backs of my fingers, I usually start out with the rifle rested as far back toward the triggerguard as possible. If I can’t get accuracy there, I slide the fulcrum forward until the groups tighten. One word of warning about using the backs of the fingers: many rifles are heavy enough to hurt when rested this way. Though it may prove to be accurate, it may also be inconvenient.
Disregard the artillery hold
In very few cases over the years, I’ve found certain guns that needed to be held tight — like a deer rifle. These are extremely rare; but if all else fails, grab on for dear life and pull the stock tight into your shoulder.
Clean the barrel
This is an old standby that simulates breaking-in the barrel. And you only do it with steel barrels. Brass barrels should never be cleaned this way. Run the correct caliber brass or bronze bore brush loaded with J-B Non-Embedding Bore Cleaning Compound through the barrel 20 times in both directions. You need to use a solid or sectional cleaning rod for this, as a pull-through will take forever.
When cleaning rifles that have sliding breeches like the TX200 and the RWS Diana 48, you’ll want to use a pistol bore brush because they’re shorter. They will clear the breech of the gun when loaded from the muzzle, making the reverse cleaning stroke much easier. You really should use a brass pistol brush, because nylon pistol brush bristles aren’t stiff enough to properly clean rust deposits from a steel rifle barrel.
This works sometimes because barrels are either full of foreign material and dirt, or they’re actually rusted. Bluing solutions will cause a barrel to rust in storage and shipment. I used to clean all the Lothar Walther barrels at AirForce after they came back from the bluer, and you would be surprised at what came out! I always left them with a film of a commercial product called Rustlick that we bought by the gallon, yet sometimes even then they would continue to rust. You never can be sure without cleaning the barrel.
If you just shoot your gun when it’s new, eventually the pellets will clean the barrel for you. They’ll also remove any burrs that are standing proud of the rifling. But to speed up the process, nothing can beat J-B Bore Paste!
Tighten the stock screws
This ought to be your first step even before attempting to shoot the gun. But we forget or we grow complacent. Many of the newer guns are designed with stock screws that just don’t loosen as much as they used to, and some companies like Gamo apply Locktite to their stock screws. Still, give those screw heads a try.
This task goes much better if you use something like a professional screwdriver set. I owns several sets like this, and they’re in constant use at my house. You’ll find that one set will have that extra-narrow Phillips bit you need for certain jobs, while another will have the wide, fat slotted bit for those huge screw heads you sometimes encounter.
Tighten the scope screws
You would not believe how many times I’ve encountered loose scope screws! It happens on firearms as well as airguns. And it’s always a detriment to accuracy. To find out if the screws are loose, I do two things.
First, I grab the gun by the scope and shake it. If the mounts are loose, this will tell you immediately that something’s wrong. But to be absolutely certain, I do physically check every screw. I’ve had the embarrassing situation arise that after doing a big article that had an accuracy section, when I’m removing the scope I discover one or more loose screws. That always makes me wonder if the gun shot as well as it could have.
The place where this is especially evasive is on mounts that are adjustable. The adjustment screws that oppose each other (I’m thinking of the B-Square design now) are often not under tension. That can lead to a problem even when the mounts are tight on the gun and the scope is tight in the rings.
The breech
On a breakbarrel air rifle, the breech is the area of greatest concern as far as accuracy problems go. A pivot pin that’s too loose can cause groups to open up, and a breech seal that stands too high can cause inconsistent closing of the breech. In fact, this is such a sensitive area that I pay particular attention to it when setting up a rifle for accuracy testing. If the barrel wobbles on the pivot pin, as so many Chinese-made breakbarrels do today, there’s little that can be done (outside of major gunsmithing) to tighten the breech. A gun with a wobbly barrel is not going shoot accurately regardless of how tight it may feel.
Along that line, someone asked about the Whiscombe I shoot. It’s both a breakbarrel and an underlever. The underlever cocks the mainsprings, but the barrel breaks open for loading. John Whiscombe designed a very positive method of enclosing this breech so it cannot get loose while the gun is operated. That’s why this spring rifle shoots almost as accurately as a PCP.
Here you can see the Whiscombe breech broken open. There are two chisel detents holding the breech shut, and a bar welded to the underside of the barrel is clamped by them. Those chisels will be on top of the bar when the breech is closed. The barrel opens and closes independent of the rifle being cocked.
You also have to look at the breech seal. Not because the gun leaks air at the seal, because that’s relatively rare, but because the breech seal often stands so high that it doesn’t allow the breech to close the same every time. So, a flat breech seal is not as much of a problem as a tall seal might be. When this is the problem, and it’s relatively rare, then you need to reconfigure the breech seal, which can take some time. I don’t have a handy rule of thumb guide for this, but the height of the breech seal can affect accuracy when it gets too high.
Summary
These are the things I do when accuracy isn’t what it should be. As I said in the beginning, the problems happen mostly with spring-piston guns; and of those, the powerful breakbarrels are the worst of all. If a CO2 gun or a pneumatic is inaccurate I suspect the barrel before anything else; and if the gun is a cheap one, it may just not have a good barrel to begin with.
I used to oil my springers a lot more than I do today. I now think over-oiling the compression chamber leads to accuracy problems more than a dry gun.
There may be a few other tricks I know, but these are the ones that come to mind when I think about guns that are difficult.
Pellet velocity versus accuracy test: Part 10
by B.B. Pelletier
Announcement: Kevin Currie is this week’s winner of Pyramyd Air’s Big Shot of the Week on their facebook page. He’ll receive a $50 Pyramyd Air gift card.
Kevin Currie is shown shooting a tuned .177 Gamo CFX with his son and dog. He says his CFX is scary accurate!
Part 1
Part 2
Part 3
Part 4
Part 5
Part 6
Part 7
Part 8
Part 9
Merry Christmas!
For those who celebrate Christmas, Merry Christmas from Edith and me! This is our last opportunity to wish you a Merry Christmas before Sunday, but I would like to hear on Monday from anyone who received an airgun, airgun-related gift or a firearm for Christmas. I’ll tell you what I got, too.
Today, we’ll look at the results of this test to see if there’s a direct inverse relationship between pellet velocity and accuracy. I’ll start with the results by pellet and see where that goes.
A word about the shooting technique
The first accuracy test I did was in Part 2 of this report. I found fault with that test, though, because of how I was shooting. I wasn’t using the scope level on the gun all the time, and I also wasn’t “seasoning” the bore by shooting several shots before starting a group. Some pellets seemed to need the seasoning, while with others it didn’t seem to matter as much. I reshot the entire first accuracy test and seasoned the bore for every pellet, plus I paid attention to the scope level.
The need for seasoning seemed to go away as testing progressed, but the scope level was always consulted for every shot. I know that the level improved the performance of every pellet that was shot. The jury is still out on the seasoning issue.
All the accuracy results seen here are not from the first time I shot the rifle, but the second. All were shot at the velocities indicated. Just the shooting techniques were adjusted as indicated.
Beeman Devastators
In this test, the 7.1-grain Beeman Devastator was the “little pellet that could.” From the start, when it was averaging 1,216 f.p.s., this lightweight hunting pellet produced 10-shot groups under three-quarters of an inch at 25 yards. That went against the popular belief that supersonic velocities are harmful to accuracy.
The Devastator turned in the following performance at 25 yards.
Velocity (f.p.s.)….Group size
1,216………………….0.743″
1,123………………….0.616″
973……………………0.724″
772……………………1.073″
Okay, you don’t need a graph to see a problem here! This pellet is obviously way more accurate at 1,123 f.p.s. than it is at 772 f.p.s. Theory says that shouldn’t be because the first velocity is breaking the sound barrier, which is where all the accuracy gremlins are supposed to live.
Looking at the group size in relation to the velocity, it appears that 1,123 f.p.s. is the most accurate velocity for this pellet in this gun. That would entirely negate the theory that velocity destroys accuracy. So, if there is such a relationship, it must be subordinate to and less influential than some other influence. I think that other influence might be vibration, but that’s just a guess.
Crosman Premier lites
The 7.9-grain Crosman Premier lite was the next pellet I tested. Here are the results of all four tests at 25 yards.
Velocity (f.p.s.)…Group size
1,134………………….0.778″
1,057………………….0.754″
915…………………….0.747″
732…………………….0.593″
The Premiers did give a linear relationship between velocity and group size, though the two groups from the middle two velocities are so close in size that they could be the same. Measuring error is greater than the difference between these two groups.
The group at the lowest velocity is obviously the best of the four and by a wide margin. The data from this pellet isn’t clear as to what is causing the accuracy improvement. It could be either velocity or vibration. However, at 915 f.p.s., the pellet is going slow enough to be out of the transonic region, while at 1,057 f.p.s. it isn’t. I would have expected to see an accuracy gain at that lower velocity that’s greater than what we see here if the real problem is just velocity.
Beeman Kodiaks
Next, I shot the heavyweight Beeman Kodiak pellet. It proved to be the most accurate pellet of this test and the only one that turned in a group smaller than a half inch. Please bear in mind that these are all 10-shot groups and are about 60 percent larger than they would be if they were only five shots. I didn’t shoot 10 shots for that reason — but because, in doing so, I reduced the probability error significantly. In short, I can trust that the group sizes shown are closer to reality that if I had shot two 5-shot groups and averaged them.
Kodiaks shot tight right from the start, even though the first group of pellets was actually close to or just within the transonic range. Since I didn’t keep atmospheric data for each day I shot, I can’t say where the sound barrier was exactly; and the transonic region, which is 0.8 mach to 1.5 mach, is calculated based on that. In practical terms, I know that 992 f.p.s. is pretty darn close to transonic, because the sound barrier can be anywhere from 1,050 f.p.s. to 1,125 f.p.s. depending on the temperature and humidity where I shoot.
Velocity (f.p.s.)…Group size
992…………………….0.633″
937…………………….0.628″
819…………………….0.472″
658…………………….0.864″
However, the groups don’t seem to support the velocity/accuracy relationship very well. It’s true that the first and second groups are too close to really say which is larger than the other, but the velocities at which they were shot are very important. One borders on the transonic, while the other is probably slower than transonic.
But look at that third group! When the velocity averages 819 f.p.s., the Kodiak loves this rifle! Is that a velocity thing or is that influenced by the harmonics of the rifle at that power level? I’m inclined to think that it’s the latter, though we do not have enough data to prove it.
The last group is the worst, though the velocity is getting pretty low for a pellet this long and heavy. We don’t know much from these results, either. But if it does turn out to be harmonics over velocity, then this pellet is probably the best one for the rifle, and the Harmonic Optimized Tuning System (HOTS) needs to be adjusted for it at around 900 f.p.s.
Eun Jin
The 16.1-grain Eun Jin pellet is too heavy for the power potential of this air rifle. Although the Whiscombe JW 75 is a 30 foot-pound air rifle — that’s only in .25 caliber — when the heaviest pellets are used. In .177, it’s much closer to 20 foot-pounds and is, therefore, too weak to drive the 16.1-grain .177 Eun Jin fast enough for accuracy.
Velocity (f.p.s.)…Group size
726…………………….0.798″
687…………………….1.118″
618…………………….1.270″
501…………………….1.724″
Starting with the second group, I could tell that the Eun Jins weren’t going to do well. Like the Kodiaks, they’re also too long and heavy to make any conclusions regarding velocity versus harmonics. They just don’t give enough speed in this rifle to properly examine the velocity question.
A different look at the data
The “sweet spot” was different for every pellet. Each pellet had one velocity at which it grouped the best; disregarding the actual velocity, it went like this:
Fastest was best—>Eun Jin
Second fastest was best—>Devastator
Third fastest was best—>Kodiak
Slowest was best—>Premier lite
That, by itself, is a pretty good indicator that supersonic speed isn’t a problem, since the Devastator was supersonic when it produced its best group. One thing you cannot do is compare the group sizes…one to another…between the pellets. Let each pellet stand alone because there are far too many variables to make a cross comparison like that.
Was the Whiscombe a valid testbed?
Some thought the Whiscombe was the wrong gun to use because it’s so inherently accurate. I disagree. I think its accuracy makes the results all the more valid. Besides, controlling many of the magnum breakbarrel springers is too difficult and gets in the way of testing. They require perfect hold technique for every shot. The Whiscombe is much easier to control, which takes that variable out of the equation.
Some felt that only a pneumatic should be used since harmonics seemed to be causing accuracy errors. Well…that was the point of testing! Now we know a little more about how the pellets respond to supersonic speed, and it seems to me that it doesn’t matter as much as many, including me, have believed. People don’t just shoot PCPs. I do plan on testing this same sort of thing with a PCP whose velocity I can control over a wide range, and those results will also be interesting — but they don’t negate the value of testing a springer.
I used the Whiscombe for this test because, even when I altered the velocity, the harmonics of the gun remained the same. The powerplant always ran at full power, regardless of how fast it shot. And the barrel was always the same, too. The only thing that changed was the velocity.
What comes next?
I’m sure some of you will have additional interpretations to make about this test, and now is the time to make them known. My next step is to use the rifle as it is currently set up and adjust the HOTS to see what I can do to the size of the Beeman Devastator group. I’m thinking the HOTS can be adjusted to shrink it significantly. I have a procedure in mind to cut the time it takes to adjust the rifle because this can take hours if you aren’t careful! I’ll share that procedure with you in that report.
If I’m right about being able to tune the HOTS to get a small group at the average of 772 f.p.s., then the next thing I’ll do is shoot another group with the bubble level taped to hide the bubble. I won’t intentionally try to enlarge the group, but I just won’t be able to consult the bubble for every shot. That will result in another group that can be compared with the best group I’m able to shoot when the HOTS is tuned, because it will still be tuned for that group.
Finally, perhaps one additional test is needed. I’ll set the rifle to shoot Kodiaks in the high 800 f.p.s. range and adjust the HOTS for the best accuracy. When I get the best group, I’ll shoot one group of weight-sorted pellets against another group of pellets selected straight from the tin.
When all of this is completed, I should be able to state what I think are the most important components of accuracy. You’ll be able to see how much difference these things really have on group size. Most of you can’t adjust the harmonics of your spring guns, so you need to find the one pellet that shoots the best. Perhaps it’s time someone made a generic harmonic tuner for springers, again.
Daisy Powerline model 35 multi-pump air rifle: Part 1
by B.B. Pelletier
Daisy’s new model 35 multi-pump air rifle is designed for youth. It’s a smoothbore with several interesting features.
Daisy calls this model 35 an air “rifle,” but it isn’t a rifle at all. It’s a smoothbore. Now, I take exception to the misuse of terminology, but I haven’t shot a smoothbore pellet gun in so long that I welcomed the opportunity to try this one.
Also, this is a new model from Daisy. Normally Daisy makes new models by painting their older guns or laser engraving them with a name other than the base gun they come from. So anything that is really new from Rogers, Arkansas, like this gun, is worth a look.
The Daisy model 35 is a multi-pump pneumatic that shoots both BBs and lead pellets, though not interchangeably. You have to decide which ammo you want to shoot, because the loading methods are different for each type. I will cover that in greater detail in Part 2.
Pellets are loaded one at a time and when you shoot them the gun is a single shot. BBs are poured into an internal reservoir that holds up to about 50. They are then fed by manipulating the gun as you load it. A magnetic bolt tip grabs each new BB from the reservoir and inserts it into the breech.
One thing I noticed about loading is you have to be careful not to let the pellet pass into the hole at the rear of the loading trough. That’s where the BBs come from and the hole is large enough to accept the pellet. If it enters the hole it could get stuck, so I found it best to roll the pellet into the trough with finger pressure, so it’s controlled and doesn’t go near the hole.
It’s a smoothbore!
Because the model 35 is a smoothbore, we get the opportunity to see how diabolo pellets perform when they are not spinning. A lot will depend on the length of the pellet, as longer pellets should tumble more than shorter pellets.
I read the customer reviews and several mentioned that the gun is difficult to scope. Scope??? This is a smoothbore gun and people want to scope it? The open sights that come on the gun are adjustable in both directions, and although they are not adjusted by precision detents and knobs, they are everything that’s needed to shoot well and have a good time. Forget the scopes for this gun, because multi-pumps are not suited to them.
Youth gun
This gun was undoubtedly made for youth. Daisy’s Powerline label applies to guns of a certain muzzle velocity and it is supposed to be for children 16 years and up, but in all other ways, this is a kid’s gun. Having a short-stroke pump makes it easy to pump to the maximum of 10 pumps, for which you are rewarded with a muzzle velocity of 625 f.p.s. with a steel BB and 605 f.p.s. with pellets. We know nothing about what pellet was used to test it, but Daisy must have used their own zinc-plated steel BBs for the BB velocity test. Therefore it will be very easy to compare the test gun to the advertised velocity.
As a youth gun the 35 is light, at just 3.1 lbs. And because there is no wood on the gun, that weight should not vary from one gun to another. The trigger is single-stage, which doesn’t appeal to me personally, but I think it’s the style preferred by more shooters. The pull is long and heavy enough to satisfy a lawyer, but it’s relatively free of creep. It isn’t crisp by anyone’s definition, but it is entirely usable and probably a good thing for youthful fingers. I’ll give you the pull weight in Part 2.
The sights are designed well and, as noted, they do adjust in both directions. Elevation is controlled by a notched elevator that slides in a slot in the rear sight leaf and windage is controlled by a screw that loosens to slide the rear notch in either direction. The front sight has a white dot , but if you light the target and keep the shooter in the dark the sight blade with appear square in the rear notch.
The front sight is a nice crisp post. You can hide the white dot with lighting, for better accuracy.
The rear sight adjusts in both directions. This photo also shows the BB loading door located on the left front of the receiver.
Maintenance
This is one of those pneumatics that looks like it cannot be stored with a pump in the compression chamber, because the bolt has to be cocked to charge the gun. Best to do it the way Daisy recommends. The pump head should be oiled, because it is just sealed by an o-ring. That makes the oil all the more important. There is a felt ring ahead of the o-ring that is accessed by opening the pump handle all the way, so it’s very easy to oil this gun. And the owner’s manual addresses this task very well
Lots of synthetic on this gun, as there must be at such a low price. What intrigues me is the nice adjustable sights and smooth bore. I’ll get a chance to see how diabolo pellets do when stabilized by just their high drag! I’m looking forward to it.
