Posts Tagged ‘Beeman Devastator pellets’
by Tom Gaylord, a.k.a. B.B. Pelletier
Today, you’ll see the test of the .177-caliber Walther LGV Master Ultra at 25 yards with open sights. This is for all who have an interest in a rifle that I think redefines the breakbarrel spring-piston sporter.
Twenty-five yards is not quite 2.5 times the distance at which the first test was conducted, so I expect to see the groups open up quite a lot. In fact, this is a wonderful distance at which to test an airgun because this is where the real pedigree starts to show through. Let’s see how our test rifle did.
Crosman Premier lite
The first pellet I tested was the 7.9-grain Crosman Premier lite that did so well in the 10-meter test. After confirming the shot was on the bull with a spotting scope, I shot the remaining 9 shots without looking again. Shot 9 was a called pull to the left, and I knew I would see a hole to the left of the main group when I examined the target.
Crosman Premier heavies
Next, I tried 10 Crosman Premier heavies because a reader thought they might do well. They did not — giving a very open and scattered group that measures 1.549 inches between centers.
Next, I shot 10 Beeman Devastator pellets. These lightweight hollowpoints surprised me in the Pellet velocity versus accuracy test I did two years ago. And they fit the LGV breech very well, so I had hopes they might be accurate, as well.
Indeed they were! Ten gave a 1.154-inch group, but 9 of them were in 0.746 inches. That’s very much like the Premier lites, though there was no called shot this time.
JSB Exact Heavy 10.34-grain
Next up were 10 JSB Exact heavys. The Exact RS pellets had not done well in the 10-meter test, but these heavier domes often succeed where the lighter ones don’t. This time, the outcome was very telling. Eight of the pellets made an incredibly small 0.518-inch group that’s perfectly round, then the final two shots enlarged the group to 2.147 inches. They made both the largest and smallest group of the session! That small inner group tells me that this may well be the most accurate pellet in this rifle, as it often is.
This group made by JSB Exact Heavy pellets will make you think! I didn’t call any shots, but I think something went wrong with the two outliers. I believe the small cluster is more representative of what this pellet can do in this rifle.
Of course, I could be wrong, but this isn’t the last time I’m going to shoot this LGV for accuracy. Next time will be at 25 yards with a scope mounted. This JSB just won a place in that test.
H&N Baracuda Match
The last pellet I tested was the H&N Baracuda Match, which did so-so in the 10-meter test. I thought I would give them another chance at 25 yards; but, alas, their mediocrity only continued. Ten made an open 2.121-inch group with no pattern or clustering.
Am I satisfied?
I am very satisfied with this performance. The naysayers will probably dream up new things to say about the gun; but as far as I’m concerned, it’s on track for a spectacular test.
I will say that the firing behavior was quite buzzy with the Premiers, but much less so with the Baracudas and the heavy JSBs. I think those JSBs are going to turn out to be the pellets of choice in this rifle. I’ll also comment that the trigger now seems as good as a well-adjusted Rekord. It’s not as light, but the wide blade makes the release feel very crisp.
by Tom Gaylord, a.k.a. B.B. Pelletier
This Diana 25 smoothbore was made in World War II.
Today’s blog falls under the heading, “It’s not always a good idea to try everything.” Back when we were exploring the Diana 25 smoothbore airgun, we saw how incredibly accurate it was with certain pellets at 10 meters.
This 10-shot group of JSB Exact RS pellets was shot at 10 meters. The extreme spread measures just 0.337 inches between centers! It made us all wonder just how accurate a smoothbore pellet gun can be.
When I backed up to 25 yards, however, the groups opened up to between 2.5 and 3+ inches for the same pellet. Obviously, the pellet needs to be stabilized by both the high drag of its diabolo shape and by the spin introduced by rifling. Drag, alone, is not enough to stabilize the pellet.
One reader then asked me to try shooting round lead balls in the gun. Today, I’ll conduct that test for you.
Beeman Perfect Rounds
I shot Beeman Perfect Rounds, which are H&N Rundkugel but under the Beeman label. They weigh 7.7 grains, which is the weight of a medium-weight diabolo pellet.
The balls fit the Diana’s breech quite well, though one was slightly larger than the others. But the rest would not drop into the breech and had to be seated with the thumb — just as a pellet would. They did seat easily, however, and I noticed the gun’s powerplant seemed harsher than it is with pellets. I suspect the balls had less resistance than a pellet since they only touched the bore at their circumference, and there’s no rifling to engrave them.
Except for one, each round ball fit the gun’s breech very well. Most stopped like this and had to be gently pressed into the bore with the thumb.
Testing at 10 meters
I began the test at 10 meters, thinking the gun was accurate at that distance with diabolos, so it should be accurate with round balls. I’m sure the reader who asked me to test round balls must have thought the same thing. But when I fired the first shot and could not find the hole on the target paper, I stopped shooting. Fortunately there were no new holes in the wall!
I then moved up to 12 feet and shot again — this time standing and using the door jamb as a brace. The shots now went to the bull at which I was aiming. But the group is hardly worth celebrating. Ten shots went into 1.166 inches at this distance. I’ve shot many BB guns that could do so much better than this that it’s embarrassing to consider.
Ten shots from 12 feet did make a group on the target, but that’s way too close for a gun like this! Group measures 1.166 inches between centers.
I guess the Diana 25 isn’t made to shoot round balls. If there was any doubt before, I hope this clears it up. I didn’t shoot any more groups because of how harsh the powerplant seemed to be. I didn’t see any reason to strees the mechanism more than I already had.
Shooting round balls got me thinking about other types of non-pellet projectiles, and of course darts came to mind. I decided not to try them in this gun,as the powerplant is too powerful for them. It would bury a dart deep in wood, causing its destruction upon extraction. But that did give me another idea.
I was recently asked to conduct a retest of a gun I tested some time ago. Apparently, a blog reader felt my results were not typical of the gun I tested, so he called the manufacturer and they contacted me. That gun in question is a smoothbore, as well, and it’s a multi-pump, so the velocity can be controlled. I plan on testing darts when I test that gun for you.
by Tom Gaylord, a.k.a. B.B. Pelletier
This Diana 25 smoothbore was made in World War II.
One thing that I really like about this blog is the fact that it affords me the opportunity to test certain things thoroughly. In fact, it somewhat forces me to test them thoroughly; because as I test and write, I think about you readers and all the questions you’ll have for me. So, I test to be able to tell you as much as I can about our mutual interests.
This Diana 25 smoothbore airgun that I’m reporting on today is one such subject. I get to work with a vintage airgun that’s very enjoyable, plus I get to test how well diabolo pellets stabilize and how accurate they are when they don’t spin. In turn, that reflects on the test of how the rifling twist rate affects accuracy.
I tested this airgun at 25 yards — a serious distance at which any and all airguns will show their true colors. And I used 10-shot groups, another tool in our growing bag of diagnostic accuracy tricks. Just one group can reveal significant findings, instead of five 5-shot groups or, worse yet, I shoot a bunch of 5-shot groups and show only the best one.
I was on the rifle range last week with a young man who was shooting a .257 Weatherby Magnum and trying to get it to group. He obviously knew what accuracy is because he wanted groups that measured under .75 inches at 100 yards. But he was shooting only 3-shot groups! That isn’t enough shots to make more than a good guess about a rifle’s potential accuracy. When I called him on it, he pointed out that he was pasting his targets to a backer at the same place every time, so all his shots would overlap on the backer as he changed targets. That told me he’s afraid of shooting large groups in case he makes a mistake. I’ve been there and done that, too!
Today’s test frankly frightened me, as I wasn’t sure the gun was accurate enough to hit the pellet trap all the time. I decided to use the JSB Exact RS pellets that performed so well at 10 meters. I seated each pellet deep in the bore with the Air Venturi Pellet Pen and Pellet Seater because the 10-meter test showed that was the way the gun likes it best. Let’s look at the two targets from that test before I continue.
The flush-seated JSB Exact RS pellets made a 10-meter group that measures 1.158 inches between centers.
The same pellets seated deep made this 0.337-inch group at 10 meters. It looks significantly smaller!
The first shot at 25 yards did hit the target paper, but it was high and outside the bull. I checked it with a spotting scope immediately after shooting it. I also checked after the second shot, just to make sure it was also on the paper. It was, so after that I settled down and put 8 more shots into the target. In the end, they were all high and formed a group that measures 3.879 inches between the centers of the two widest shots. So that’s what the gun seems to be capable of, but I wanted another 10-shot group, just to confirm it.
I lowered the simple rear sight elevator for the second group and fired 10 more JSB Exact RS pellets. The first shot hit the target in the black, so I knew I was okay to complete the 10 shots without looking. At the end, I had 10 shots in a 3.168-inch group. As far as I was concerned, those two targets demonstrated the accuracy potential of this smoothbore pellet gun at 25 yards with deep-seated JSB Exact RS pellets. But something nagged at me.
How much worse would this gun shoot pellets that were only seated flush with the breech — in other words, loaded in the normal way? I had to test it. Once more, I shot 10 shots at 25 yards. This time, I was really scared because it looked from the 10-meter test that these pellets might not all hit the paper. Would this group be over twice as large as the other two — like the 10-meter group was? But the first shot went into the bull and the second one landed very close, so I calmed down and shot the other 8 shots without looking again. In the end, I had a 10-shot group that measures 2.421 inches between centers — the smallest group yet at 25 yards!
What had happened? The gun was shooting more accurately at 25 yards with pellets seated flush, when it had clearly shot deep-seated pellets best at 10 meters? Not knowing what else to do, I shot a second group with the pellets seated flush. This time the group was larger, but at 2.957 inches it’s still the second-best group of the test.
What have we learned?
This test demonstrates that diabolo pellets do stabilize from their high drag, alone. They do not require a spin to stabilize them because they all hit the target nose-first. But they’re not as accurate as they would be if shot from a rifled barrel. The spin introduced by rifling is important for accuracy, if not for stability.
A second lesson is this: Even though I shoot and record 10-shot groups, a single group may not be enough data. The difference in accuracy at 10 meters and 25 yards between deep-seated pellets and flush-seated pellets would seem to indicate that. Or it could just be that deep-seated pellets are more accurate at 10 meters, but flush-seated pellets are more accurate at 25 yards. If that’s the case (and I don’t know that it is), I have no idea of why it would be that way.
I think I need to test this gun once more and shoot 3 10-shot groups with each type of seating at each distance before we’ll know anything for sure.
by Tom Gaylord, a.k.a. B.B. Pelletier
This Diana 25 smoothbore was made during World War II.
What a topic to follow a twist-rate report — one about a smoothbore! Today, we’ll look at the accuracy of the WW II-era Diana 25 smoothbore airgun. This is a play-day for me because this gun is so non-finicky and trouble-free. It’s the way I wish all airguns could be. Just load and shoot. No special handling beyond the basic artillery hold, and no need to treat it like it’s a vial of nitroglycerin.
Shoot from 10 meters
I decided to shoot from a rest at 10 meters just because this is a smoothbore, and I had no idea of what results we would get. I hoped it would hit the paper with all shots. That would be good enough. But nothing beats shooting, so that’s what I did.
JSB Exact RS
The first pellet I tried was the JSB Exact RS, which is a .177-caliber favorite of blog reader Kevin and has become one of mine, too. It seems to work in most airguns, and it’s often one of the very best pellets. So, how would it do in a smoothbore?
I shot off a rest with the artillery hold. My off hand was back touching the triggerguard, but the gun is not muzzle-heavy. The first shot landed below the center of the bull — but actually at the point of aim, if a bit off to the right. So, the rear sight elevator was pushed forward to raise the sight. I didn’t care if it was hitting the center of the bull or not, but I wanted to keep the shots mostly inside the large black bull of a 10-meter pistol target because I could see the holes when they were in the white and distracted me.
The first 10 shots were fired with the pellet seated flush with the breech face. And the group turned out better than I had expected, though about as good as several readers had indicated they get from their smoothbores. It may not look that good to you, but notice how narrow it is compared to the height? That’ll become important in a moment. This group measures 1.158 inches between centers.
Next, I shot another 10 rounds of RS pellets, but this time I seated each pellet deep in the breech with the Air Venturi Pellet Pen and PellSet. As before, the pellets all landed in the black bull, so it wasn’t until I walked down to change the target that I saw the group. Imagine my surprise to see a 10-shot group that could just as easily have been shot with an expensive target rifle! Ten JSB RS pellets went into a group that measured 0.337 inches between centers.
You might shoot 5 shots some time and luck out like that, but 10 shots tell the truth. This airgun is very accurate at 10 meters, even though it’s a smoothbore. And it takes deep-seating the pellets to do it — at least with the JSB RS pellet. Now, I was curious. Would the two other test pellets show similar results?
The second pellet I tried is one I don’t shoot a lot, but after it did so well in the Velocity versus vibration accuracy test I did a year ago, it has moved into the category of pellets I like to try when the circumstances are unusual. The Beeman Devastator is a hollowpoint that acts like a wadcutter at the same time. And a smoothbore is definitely unusual. The first 10 flush-seated pellets went into a group measuring 1.948 inches between centers. Not very good and more like what I’d been expecting from this airgun.
Now, it was time to shoot 10 Devastators that were seated deep in the breech. Would they also tighten up?
Well — yes and no. The 10-shot group of deep-seated Devastators measures 1.982 inches between centers, which is a little larger than the group of flush-seated pellets. However, 8 of those pellets did group into 0.691 inches. I would say that the deep-seating method still looks promising at this point.
The final pellet I tried was that universal favorite — the RWS Superdome. The first group of flush-seated pellets was not that large, at 1.156 inches. If the deep-seating method held true for this pellet as well, it might beat the tight RS group when seated deep.
A happy accident
As I was shooting the next group of Superdomes, I forgot to seat the second pellet deep and had to stop shooting the target. But the result on target was so dramatic that I photographed it, so you could see what happened. The deep-seated pellet is the high one and the flush-seated pellet is the low one. That shows more clearly than anything how deep-seating affects the shot.
Then I got serious again and shot 10 rounds of Superdomes seated deep. They made a group sized 1.047 inches. While that’s only a little better than the same pellets seated flush, notice that these shots are centered in the bull much better. Not that I’m looking for that, but it’s a nice side benefit.
What have we learned?
The first thing this test has taught us is that a smoothbore airgun isn’t that much of a disadvantage at 10 meters. I think the results of the RS pellets definitely call for another test of this airgun at 25 yards.
The next thing I learned is that deep-seating the pellets seems to improve their accuracy. Some improved more than others, but every pellet seems to have done better with deep-seating.
The last thing is that all of this shooting, all 63 shots, were fired with simple open sights. After some of the trauma you’ve witnessed me undergo in recent weeks to get some air rifles to group, this little Diana 25 seems to have breezed past all the big-name guns and taken the lead. I think that says a lot about what power levels are best for spring-piston air rifles.
by B.B. Pelletier
Dammion Howard (left) shows off some new airguns he found under the tree this year!
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 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.
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.
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.
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.
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.
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.