Archive for June 2013

If I were you…

by Tom Gaylord, a.k.a. B.B. Pelletier

A couple days ago, I was surprised to see a very technical discussion in the comments section of the Mosin Nagant sniper rifle written by our own Matt61. I remarked that I remembered a time when Matt was new to almost everything in the shooting world. He was exploring multiple avenues of the hobby and asking, in the words of another reader, “billions of questions every day.”

That got me thinking, which is sometimes dangerous, but always interesting. My thoughts ran to things like what I was like when I was just starting out in this world of shooting. It was back in the 1950s and ’60s and there was no internet, so I learned much of what I knew from reading books and magazines and by talking to whoever would tell me about guns. Unfortunately, I didn’t know any real shooters, and the stuff I did get was mostly untrue or outright lies that were calculated to keep me from trying out things on my own.

I remember one thing I was told by my mother and stepfather about my grandfather’s Colt Army Special revolver in .38 Special caliber. They didn’t want me shooting the gun that was mine (inherited from my father), so my stepfather told me that the metallurgy of old guns crystalized with the passage of time and this gun was likely to blow up if shot. I bought that line for a couple years; but when it didn’t agree with my readings of Elmer Keith in Guns & Ammo, I finally gave the old girl a try. Of course it didn’t blow up, and I discovered that I was a pretty fair shot with a handgun at the same time. Imagine that!

Then there was the fiction of the .44 Magnum revolver being not only the most powerful handgun in the world (Dirty Harry timeframe), but also a gun that kicked so hard the front sight would come back and hit you in the forehead! Imagine my disappointment to discover that the first .44 Magnum I fired kicked only a little harder than a .357 Magnum revolver I was already very used to. Chalk up another experience that didn’t go as advertised.

As a youngster in Ohio, I had friends who told me that a 12-gauge shotgun would kick me like a Missouri mule. They had seen their younger brothers “knocked back three feet” by the recoil of this fearsome beast. But when I shot one, it didn’t seem much different than the 16-gauge shotgun I was already using. “Well,” they said, “maybe you can stand that, but don’t even think of shooting a 10-gauge. It will knock you flat!” I still haven’t tried one, so perhaps they’re right.

At this same time, I was getting loads of “information” about those magical Benjamin pump-ups that were “just as powerful as a .22 short.” If you pumped one 50 times it would crack like thunder and you couldn’t tell the difference between it and a rimfire.

Then there was the full-auto craze. Like most boys of my era, I was brought up on tales of Elliot Ness and the Chicago Typewriter that could destroy whole blocks of the Windy City when fired indiscriminately in artificially long, continuous bursts from the open windows of speeding gangster cars. So, the reality of dumping a 30-shot stick magazine from an M3A1 grease gun 10 years later was a huge letdown. As was seeing 15 M2 ground-mounted machine guns on a firing line fail to hit a 5-foot by 20-foot cloth banner trailed behind a Remote Controlled Aerial Towed Target (RCATT) drone that flew down the line at 150 m.p.h. 150 feet away! Until then, I thought machine guns were always able to hit their targets. After seeing they couldn’t, I wondered how they ever hit anything that wasn’t standing still.

Then there was the mystique of the Desert Eagle pistol. I had heard it was an awesome gun, that flattened things at both ends — muzzle and grip — equally. A few years ago, I shot one in .44 Magnum and found that it was only slightly harder-recoiling than a 1911 pistol chambered for .45 ACP. What a huge letdown that was. Now, I own a Desert Eagle in .357 Magnum, and that’s only until I can trade up to the .44 that’s the lightest-recoilling big bore handgun I’ve ever fired.

The moral of the story
Don’t take anyone’s word for how bad, how powerful or how effective any gun is until you try it for yourself. Most of the time, they exaggerate. Find out for yourself.

Some things are true!
There are, however, some things that have been true when I tested them. For example, the .250/3000 (.250 Savage) caliber is a much softer-recoiling cartridge than the Winchester .243, despite being nearly equivalent in power. I don’t know why that is, but I’ve demonstrated it repeatedly.

Or the fact that the .223 Remington can be an accurate round! All my life, I have seen it used only in ARs that spray like fire hoses; but when I finally shot one that had a barrel with some pedigree, the doggone thing actually grouped! Not quarter-inch groups (yet), but 10 shots in three-quarters of an inch at 100 yards…and some that were a little better!

What’s this got to do with airguns?
A lot of firearm talk, so far. What about airguns? Well, with a few exceptions, like the Benjamins mentioned earlier, most of my airgun experience has been first-hand rather than driven by rumors. When I hear a good rumor about an airgun, I test it if I can. Then, I pass along my results to you. Not that I know everything or don’t make a lot of mistakes along the way, but I try to tell you things I would if you were standing next to me and we were about to test the gun in question.

That’s why this report is titled If I were you….Because I tell you things I really think you would want to know. Things like how nice the Benjamin Marauder is and why I like the AirForce Talon SS so much. When I went on and on about the new Walther LGV Challenger a couple months ago, that was me being me.

Some people think I’m simply pushing airguns at you all the time. But that isn’t the case. If an airgun has any drawbacks, the last thing I want is for you to buy it because you think I recommended it. And I do get to see a lot of airguns that have shortcomings. When a great one comes along, it’s such a rare event that I tend to shout it from the rooftops.

I’m not afraid of what you’ll think about the guns I recommend. That doesn’t mean there won’t be a real lemon in the bunch from time to time. It happens to everything, and I can’t protect anyone against it. So, when I recommend a gun to you, it’s because I believe there’s a good chance the gun will be as good for you as it was for me. You and I may differ on what constitutes a good thing, which is why I report the results and let you make the decisions. But every once in awhile, something really great comes along and I cannot restrain myself from saying “If I were you…”

Big Shot of the Month
Pyramyd Air’s Big Shot of the Month is Donald Liverance. He’ll receive a $100 gift card. Congratulations! If you’d like a chance to be the next Big Shot, you can enter on Pyramyd Air’s Facebook page.

Pyramyd Air Big Shot of the Month

Donald Liverance is the Big Shot of the Month on Pyramyd Air’s airgun facebook page.

Secrets of loading the Benjamin Marauder magazine

by Tom Gaylord, a.k.a. B.B. Pelletier

Benjamin Marauder
Benjamin Marauder

Benjamin Marauder magazine

Marauder magazine

I’m writing this report for blog reader Michael and for all those who have trouble loading their Benjamin Marauder magazines. Also, Matt61 wrote that he’s read of numerous problems with this mag, and he hopes that I’ll show how it works.

Folks — the only problem with the Marauder magazine is that it isn’t straightforward, and the instructions how to load it are not clear. Loading involves a couple techniques that aren’t obvious or explained; but once you learn them, the magazine is easy to load.

Michael asked if Crosman had changed the mag. The answer is yes, but I bet 99 percent of airgunners have never seen the first magazine they made. The first Marauder magazine inserted into the left side of the rifle’s receiver instead of the right side. It was the mirror image of the magazine they use today. It worked perfectly, but it didn’t permit a scope with a large side-adjusting parallax wheel. So, Crosman switched the sides the mag works on very early in the life of the Marauder; and since then, it has inserted from the right side.

Benjamin Marauder old style magazine
The first Marauders had magazines that were installed from the left side of the receiver, like this one.

What I am about to show you works for all Marauder rifles, Marauder pistols and for the Rogue rifles. The magazine has a clear plastic cover that’s rotated to fill the magazine. This is where all the confusion comes from. The magazine cover has to be lifted over a small plastic bump on the body of the magazine in order to rotate freely.

Benjamin Marauder magazine shelf
Insert the tip of a finger into this notch under the clear magazine cover and lift up slightly while pushing the cover clockwise.

Then, the cover is pushed clockwise to clear the bump. Once the bump has been cleared, the cover can be rotated approximately 300 degrees — to a spot where the oval loading hole in the cover almost aligns with the first pellet hole in the magazine body. But the oval loading hole and the pellet hole do not yet align. You cannot put a pellet into the hole yet.

Benjamin Marauder magazine cover past bump
The cover was lifted and pushed past the bump on the magazine body. It rests against the bump under spring tension.

Benjamin Marauder magazine cover rotated almost all the way
The cover is rotated as far as it will go without help. Notice it is stopped by the bump. I have to hold it here, because it is under spring tension.

Benjamin Marauder magazine cover rotated almost all the way top view
Here is a top view of the cover in the same position. It is impossible to put a pellet into the magazine through the oval hole in the cover when it’s in this position.

This is where the Crosman instructions end, and it is the secret to loading the Marauder magazine because the cover has to be rotated a few more degrees clockwise. The bump is in the way, so the cover must be lifted again to clear the bump. The cover will now rotate about another quarter-inch until it comes to a stop on its own, and the first pellet hole will be aligned perfectly.

Benjamin Marauder magazine cover lifted and rotated past bump
Here the cover was lifted and pushed past the bump until it stopped. Now the pellet hole is wide open to receive the first pellet. Remember to place your finger on the underside of the magazine, to prevent the pellet from slipping through the hole.

That hole goes through the magazine body and is used for all 10 pellets because the bolt probe pushes all pellets out of the magazine and into the barrel. You must put the tip of your finger under the back of the hole (the barrel side of the magazine) when you drop in the first pellet.

Benjamin Marauder magazine first pellet loaded with finger in place
The first pellet is in the magazine and held there by my finger over the bottom of the hole.

Now, rotate the cover back counter-clockwise past the bump, and the magazine will be tensioned. You can release your finger from the bottom of the hole because the pellet you loaded will hold the magazine in place. The magazine cover can now be rotated back (counterclockwise) to align the oval hole with each of the remaining 9 pellet slots. Most pellets will just drop in on their own when the holes line up…but sometimes it may be necessary to push in a pellet because the skirt is too wide. A ballpoint pen helps with this.

Benjamin Marauder magazine cover rotated past bump to hold the magazine in place
By rotating the magazine cover back past the bump, the mag is held under tension by the first pellet. Loading the remainder of the magazine is now a matter of rotating the cover and aligning the loading hole with each pellet hole.

Benjamin Marauder magazine cover rotated back to the bump
The cover is no longer under tension and can be rotated back to the bump, inserting pellets as you go.

When the cover is all the way back to the bump again, lift it slightly and return the cover to the starting point with a click.

Removing and inserting the magazine
A second question I got was how to load the magazine into the receiver and remove it again. Some people feel their rifles are very tight and this task is difficult.

Benjamin Marauder removing magazine
Remove the magazine from the rifle by first cocking the bolt, then pushing on the left side of the magazine.

The secret here is how tight the magazine fits the receiver. It does pop in, but the fit is very tight. To remove it, push it out from the left side with your thumb. DO NOT try to pull it out, as that doesn’t work.

To insert the magazine, make sure the flat part of the magazine bottom is aligned with the bottom of the breech cutout. Of course, the single-shot adapter must be removed from the gun before you try to load a magazine. The mag slides into the receiver almost all the way, and when you push it in the final quarter-inch, it audibly clicks into position.

Benjamin Marauder magazine inserted all but the final bit
Slide the magazine in from the right side of the receiver. When it stops, push a little more and it’ll click in place.

Summary
These instructions will seem simple once you’ve mastered them. But until that time, the Marauder magazine seems to fight you at every turn.

Once you’ve correctly loaded the Marauder magazine, you’ll find that it’s trouble-free and very reliable.

Below is a a short video I made that recaps what I described in this blog. Remember to turn on your speakers.

How does rifling twist rate affect velocity and/or accuracy? Part 10

by Tom Gaylord, a.k.a. B.B. Pelletier

Part 1
Part 2
Part 3
Part 4
Part 5
Part 6
Part 7
Part 8
Part 9

Today, we’ll begin looking at the effects of the rifling twist rate on the accuracy of our test AirForce Talon SS rifle in .22 caliber at 50 yards. If you’re prone to jumping to conclusions before all the data is in, I have to caution you that today’s test will look bad because I’m testing the custom barrel that has the 1:22″ rifling twist. We know from the earlier tests that this barrel was most accurate at 10 meters on power levels zero and 6. Above that power level and also out at 25 yards, the accuracy of this twist rate broke down. So, it would be reasonable to assume that this barrel will give results that are even worse at 50 yards.

That didn’t stop me from trying my hardest to shoot well. I was able to watch each pellet go into the target paper because of the distance, and that was disconcerting when the pellets landed so far from the aim point and from each other. Let’s take a look at how the rifle did.

The day was nearly perfect, as it has to be to get good accuracy from pellets at 50 yards. The air was calm, except for some light breezes from time to time. I was able to work around these breezes and get the results I was after.

I decided not to test the rifle on zero power because of the long distance to the target. Any breeze would have so much time to blow the pellets off course that I felt it wouldn’t prove anything. So, both pellets were shot on power levels 6 and 10. That’s how I’ll test all 3 barrels.

You may remember that this barrel produced velocities that were very close to each other at power levels 6 and 10. With 14.3-grain Crosman Premiers, the respective velocities were 840/854 f.p.s.; and with 15.9-grain JSB Exact Jumbos, the velocities were 817/815 f.p.s. We expect the pellets in this test to go to the same place on the target, and I would expect the two groups for each pellet to be pretty similar in size.

Crosman Premiers
I started with Crosman Premiers and the power set to 10. I did not adjust the scope since completing the 25-yard accuracy test and the center of the group landed about 3.9 inches below the aim point. Ten pellets went into a group that measures 2.04 inches between centers.

Talon SS rifle Premiers 50 yards power 10
Ten Crosman Premiers went into 2.04 inches at 50 yards on power setting 10. The center of this group was about 3.90 inches below the aim point with the scope set for 25 yards. The pellet at the top center is part of another group — not this one. I did account for the full size of the pellet on the left that just clipped the edge of the target paper.

On power setting 6, the center of the group also struck the target 3.90 inches below the aim point. These measurements of the groups are just approximate since the center of each group was difficult to locate precisely. The 10-shot group size on power setting 6 was 2.607 inches between centers. This is slightly larger than the group shot on power setting 10.

Talon SS rifle Premiers 50 yards power 6
Ten Crosman Premiers went into 2.607 inches at 50 yards on power setting 6. The pellet hole at the lower right is not part of this group.

JSB Exact Jumbo
Next, it was time to test the JSB Exact Jumbo pellet. I started with power setting 10. The center of the group landed about 4.25 inches below the aim point.

Ten pellets shot on power setting 10 went into a group that measures 2.509 inches between centers. The group is much taller than it is wide.

Talon SS rifle JSB Heavys 50 yards power 10
Ten JSB Exact Jumbo pellets went into 2.509 inches at 50 yards on power setting 10. The group is taller than it is wide for reasons unknown.

On power setting 6, the 10-shot group size was 3.222 inches between centers. This group is considerably wider than the group shot on setting 10. Why that is, I have no idea.

Talon SS rifle JSB Heavys 50 yards power 6
Ten JSB Exact Jumbo pellets went into 3.222 inches at 50 yards on power setting 6. The group is quite a bit wider than the group shot on power setting 10. I have no idea why that is.

Conclusions
As expected, neither pellet did especially well at 50 yards with the 1:22″ twist barrel. They did stay closer together than I expected, however.

The Premiers were more accurate than the JSBs, which parallels what both pellets did at 25 yards.

I don’t see any real evidence of tumbling pellets with either pellet on either power setting, so it’s too simple to say they’re just destabilizing. They’re less accurate but still stable at this distance. There’s probably something profound in that — something like the pellets still fly point-forward, but erratically. I can’t prove anything, yet, but now I have one barrel’s results in the can and it’s time to look at the factory barrel next. And that one has the twist rate that the manufacturer thinks is best for this airgun.

Final note
When I pitched the idea for this test as a feature article for Shotgun News, the editor told me he has never seen a test like this before. Neither have I. This may, in fact, be the first time anyone has published the results of testing three rifled barrels of different twist rates in the same gun under the same conditions. It probably has applications in the firearms world as well as for airguns. So, you readers may be in on something that’s being done for the first time.

We still have to test the factory barrel and the 1:12″ twist barrel at 50 yards. As a final report, I’ll summarize the entire test and the lessons I believe it teaches us.

Benjamin Marauder PCP .177-caliber air rifle: Part 2

by Tom Gaylord, a.k.a. B.B. Pelletier

Part 1

Benjamin Marauder
Benjamin Marauder

This is a look back at an air rifle that has become iconic throughout the world — the Benjamin Marauder. The last time I looked at this rifle, I did it in my conventional way. This time I’m doing it different because I know more about the rifle.

My goal this time is to tune the Marauder exactly as I want it to shoot. I think there will be a great benefit for those who want to learn about PCPs to watch this as it develops. Today, I’ll test the rifle for velocity in the conventional way, except I won’t do a shot count — not today.

In the next report, I’ll test the rifle for accuracy at 25 yards, only I’ll stack the deck by selecting the pellets that I believe will be the most accurate. The accuracy test will tell me which one(s) to select. After that, I’ll test that one pellet for velocity and for the total shot count I can get.

Then, I’ll decide what I want that pellet to do. If it’s a heavyweight, I’ll try for moderate velocity in the 850 f.p.s. range and then try to get the greatest number of shots from it. If it’s a medium or lightweight pellet, I’ll probably dial the velocity back to about 900 f.p.s. and try for the best shot count.

I’ll also be interested in the fill pressure. If I can get 25 good shots with 2,500 psi air, I won’t care that 3,000 psi air gives me 31 good shots with the same pellet. But if 3,000 psi gives me 38 good shots compared to 25 good shots with 2,500 psi, then, yes, I’m going to set the gun up to fill to 3,000 psi.

As I do all of this experimentation, I’m going to document it so those who have questions about the Marauder can see how it works. You tell people today that an air rifle has adjustable velocity, and they expect to see a rheostat on the side of the stock; but the Marauder isn’t like that. It’s a thinking man’s airgun. You set it and forget it. You don’t keep fiddling with the controls until it’s a jumbled mess. We’re going to spend the time to learn how to do it right.

But wait…there’s more! Not only does the Marauder allow you to adjust the velocity of the pellet, it also lets you adjust the maximum fill pressure of the air reservoir. When you hear that, you probably wonder why anyone would bother with a fill pressure other than the maximum — which in the case of the Marauder is 3,000 psi. Here’s why they do it. Some owners may use hand pumps that they find difficult to use above 2,500 psi. Other owners may use scuba tanks, but they live 40 miles from the dive shop and want to be able to use their rifle for a longer time than conventional wisdom permits. For these owners, adjusting the maximum fill pressure to 2,500 psi makes perfect sense. They understand that they’ll get fewer shots at maximum velocity when the fill pressure is lower — just as you understand that you can’t go as far on a gallon of gas as you can when the tank is full, but you can go just as fast.

When you’re adjusting the velocity and the maximum fill pressure, you have to find a balance point between the two. That’s what’s confused many people. The Marauder is the first air rifle in the world to allow both the fill pressure and the velocity to be adjusted. It’s like they’ve given you your very own NASCAR engine, and it’s up to you to tune it for the race track you’re going to drive on.

One pellet is all I want
I don’t care to discover 27 different pellets for this rifle. I only want the single best one. I don’t care how much it costs — only how accurate it is and how effective (power and shot count) I can make it. So, that’ll take some time to locate and some more time to set up the gun to use that single pellet most effectively.

That’s what I intend doing. The first step is to test the rifle for velocity now. I plan to test the following pellets:

Crosman Premier 10.5-grain (Premier heavy)
Crosman Premier 7.9-grain (Premier lite)
JSB Exact Heavy (10.34 grain)
JSB Exact RS
RWS Superdome
Beeman Kodiak

I may not have included your favorite .177 pellet on my list, but allow me to explain my thinking. First, all of these pellets are domes. I know the domed pellet to be the most accurate pellet shape on the market. And each of the pellets I selected to test are known by me to be very accurate.

I selected the Beeman Kodiak, but I’ve found that the Beeman Kodiak Match, H&N Barauda and H&N Baracuda Match are all the same pellet, as far as performance goes. I use them interchangeably, so I only have to test one to know how all four perform.

There may be other pellets that are better in the Marauder; but starting from zero, these pellets are the ones I would choose. Let’s see how they do.

Crosman Premier heavy
Crosman Premier heavies averaged 943 f.p.s. with a spread that went from 941 to 945 f.p.s. That’s right — only 4 f.p.s. separated the fastest and slowest shots! At the average velocity, this pellet makes 20.74 foot-pounds of energy at the muzzle.

Crosman Premier lite
Crosman Premier lites averaged 1,015 f.p.s. The low was 1,012 f.p.s. The high was 1,018 f.p.s., so 7 f.p.s. was the total velocity spread. At the average velocity, this pellet produces 18.08 foot-pounds of energy at the muzzle.

JSB Exact Heavy
JSB Exact Heavy pellets averaged 936 f.p.s. The low was 932 f.p.s. and the high was 940 f.p.s. The total spread is 8 f.p.s. At the average velocity, this pellet produces 20.12 foot-pounds of muzzle energy.

JSB Exact RS
JSB Exact RS pellets averaged 1,032 f.p.s. The spread went from a low of 1025 f.p.s. to a high of 1039, so a total spread of 14 f.p.s. At the average velocity, this pellet makes 17.34 foot-pounds of energy at the muzzle.

RWS Superdome
Of all the pellets tested, RWS Superdomes were the most difficult to load into the magazine. I had to use a pusher to get almost every pellet into the mag. They averaged 1,014 f.p.s. and went from a low of 1,008 f.p.s. to a high of 1017 f.p.s. Total spread was 9 f.p.s. At the average velocity, this pellet produced 18.95 foot-pounds of energy at the muzzle.

Beeman Kodiak
Beeman Kodiaks averaged 957 f.p.s. in the Marauder. The high was 960 f.p.s and the low was 955 f.p.s., so the spread was 5 f.p.s. Kodiaks produced an average 21.66 foot-pounds of muzzle energy.

Where are we?
I just dumped that data on you so I could get to this discussion. What do these numbers tell us? They tell me my rifle is set up extra-hot. I have no need for all that speed; so after I find the right pellet, I plan to dial back the power to between 850 and 900 f.p.s. If the best pellet is light, I’ll let it go toward the 900 f.p.s. side of that range. If it’s a heavy one, I will try to get it down to around 850 f.p.s.

Why would I do that? To get additional shots per fill. The way the rifle is now set up, I’m wasting air. Not that too much air blows out with every shot, but I just don’t need these pellets to go so fast, to do what I want them to.

Did you notice?
I was impressed by how tight the shot strings were. Remember, the Marauder doesn’t have a regulator. It’s doing all this with just a well-balanced valve. We’ll want to keep that in mind when it comes time to make adjustments.

The magazine is superior!
There have been a lot of negative comments on the Marauder’s spring-loaded magazine. I can shed some light on that. I’ve watched some new owners who were befuddled by how this magazine works, and they ruined it by forcing it when it didn’t do what they expected it to. My magazines are several years old and with hundreds of shots run through each of them. I’ve never had a single problem. But force them even one time to do what they weren’t designed to do, and you’ll ruin them. This mag is a copy of a successful UK PCP magazine, and that one had the same learning curve problems.

Silent operation
My test Marauder is very quiet! Even operating at the high power level it’s at right now, it’s extremely quiet. I don’t know if it’ll get even quieter when I cut the power, but I do plan on observing and reporting.

More about the stock
The Marauder stock is not as clunky as people say. In fact, the pistol grip is thinner and narrower than most UK PCP stocks. The forearm is wide, but only enough to contain the large reservoir.

The trigger
I’m ambivalent about adjusting the trigger because the one on my rifle is so sweet that I don’t want it to change. It’s exactly where I want it to be. Theoretically, I can always adjust it back, but I’ve seen too many instances where the theory didn’t pan out.

The 2-stage trigger breaks at less than 11 oz. The first stage is 9 of those ounces, so the release is very light and glass-rod crisp. Only the addition of an overtravel stop would make it better.

So far
I knew what the Marauder was like before this test began. That’s why I’m testing it the way I am. I get to learn something new, and people who are interested in the Marauder get to see it in a way they probably haven’t seen anywhere else. I think the Marauder is a classic for all time, but you have to decide that for yourselves.

Gamo Whisper Fusion IGT breakbarrel air rifle: Part 4

by Tom Gaylord, a.k.a. B.B. Pelletier

Part 1
Part 2
Part 3

Gamo Whisper Fusion IGT air rifle
Gamo Whisper Fusion IGT air rifle.

Today will be a very interesting report, in my opinion. The Gamo Whisper Fusion IGT air rifle I’m testing turns out to be a fascinating airgun in many ways. Let’s get right to the report.

Today we will look at accuracy at 25 yards with the scoped rifle. The first thing I had to do, therefore, was mount the scope. The rifle came with a scope installed in a one-piece scope mount. Its vertical scope stop pin was already correctly adjusted to fit the stop pin hole in the raised mount on top of the rifle’s spring tube. That is rare, in my experience. Normally, the scope will be installed correctly in the mount but has to be taken out of the mount to sufficiently adjust the height of the stop pin.

I’d used this mount for my report on shimming scope rings, so I did remove the scope from the rings after all. Following that report, I left in the one shim that was shown in the report. The mount Gamo included with the test rifle has four screws per cap and seems to be a good one. It’s a one-piece design that does limit the positioning of the scope, but I was able to locate it fine for my use.

The adjustable cheekpiece helped a lot. I had it adjusted up to almost the top position, and my eye lined up with the rear of the scope with no unnatural repositioning of my head.

Surprise No. 2 was the scope. I initially sight-in at 12 feet to get the shots safely on paper, and inexpensive scopes are usually very blurry this close to the target — even if they’re set on low power. This rifle comes with a very nice Gamo 3-9X40 scope that was quite clear on 3x at 12 feet. Back up to 25 yards and boost the power to 9x, and the glass remains very clear. It’s been a long time since I liked a scope that came bundled with a gun as much as this.

The Smooth Action Trigger (SAT)
Next, I must comment on Gamo’s new SAT. It’s a 2-stage unit that has a light first stage and a second stage that you can feel as you continue to pull. The trigger blade moves through stage 2 smoothly and breaks cleanly, but not with the sudden glass-rod crispness we talk about all the time. Instead, the feel is one of movement that is predictable and can be controlled. It isn’t bad — it’s just different from other triggers.

I reported in Part 2 that the trigger breaks at 3 lbs., 12 oz. That may sound high if you read about PCP triggers breaking at less than a pound, but it really isn’t that bad. The thing to do is experience it for yourself before you judge it. I find it to be manageable and not at all troublesome to the best accuracy.

Light weight
The light weight of the rifle, on the other hand, does present something of a problem. This rifle is so light that even when the off hand touches the triggerguard, the rifle still has neutral balance. It floats in your hand. That makes it difficult to hold on the target because the crosshairs want to dance around. The solution is a very light artillery hold that does benefit the rifle’s accuracy, and I’ll address that in a moment.

Shooting
Normally, this is where I launch into the accuracy test and start making comments about the groups. This time, I have more to say, and it isn’t just about the groups — except how they helped my understand the rifle in a diagnostic way.

JSB Exact RS
The first pellet tested was the JSB Exact RS that did so well in the 10-meter accuracy test with open sights. I knew from that test that these pellets like to be seated flush with the breech for best results.

As I shot these pellets, I saw a strange phenomenon unfold. The first 3 shots were out of the bull at 5 o’clock. Then, I relaxed very consciously and allowed the rifle to float on my off hand. The next several shots went into the black. On shot 8, I didn’t relax like I should have, and I threw 1 more shot out of the bull at 5 o’clock with the first 3. How interesting!

It was so interesting, in fact, that I shot a 14-shot group, so that 10 of the shots could be fired with me being very relaxed. When you look at where they landed, you can see that the hold was all-important to where this rifle grouped.

Gamo Whisper Fusion IGT air rifle JSB Exact RS group 25 yards
This group is very large — measuring 2.574 inches between centers. But it was a learning experience for me because it demonstrated very clearly that the hold dictates where the pellets will land.

Now that I knew something about how the rifle performed, I figured I could do a lot better. And the very next group confirmed that.

H&N Barcuda Match
Next up were the H&N Baracuda Match pellets that shot second-best in the 10-meter accuracy test. Now that I knew how to hold the rifle, I expected to see a better group. And that’s exactly what happened.

I adjusted the scope after finishing the first group, moving it a few clicks to the left. The first Baracuda Match landed at 11 o’clock, just outside the bull. Shot No. 2 hit at 8 o’clock outside the bull. I was obviously holding the rifle too tight, so I made a conscious effort to hold it looser and shots 3 through 7 hit inside the black. Then, I tensed up again, sending shot No. 8 into the same hole as shot 2. The final 2 shots were fired with complete relaxation, and I had a respectable group inside the bull to the left of center.

Gamo Whisper Fusion IGT air rifle H&N Baracuda Match group 1 25 yards
This time, there were only 3 shots that missed the main group, and all of them were fired with some tension in the hold. When I relaxed, I was able to put 7 shots into 0.789 inches. I think this represents the true accuracy potential of the rifle. Total group measures 1.995 inches.

Altering the hold
Now that I understood the rifle better, I decided to move my open palm out farther so I could feel the cocking slot. Sometimes, resting the rifle this far forward is better. It certainly makes it more stable.

This time, however, there was no improvement. The group opened up, and I could see no way of controlling where the shots went. The total group measures 1.754 inches between centers, which is tighter than the previous group overall; but there’s no tighter group within this group that tells me the rifle wanted to do any better. Although this is a smaller group, I think the previous group that was shot with the off hand touching the triggerguard shows more promise. So, I went back to the other hold for the next group.

Gamo Whisper Fusion IGT air rifle H&N Baracuda Match group 2 25 yards
Ten shots went into a more scattered group at 25 yards when the rifle was rested out on the forearm.

Two pellets I didn’t try were RWS Superdomes and Gamo Raptor PBA. Both had done so poorly in the 10-meter test that I felt it wasn’t worth the time to try them again at 25 yards. That’s one of the benefits of 10-meter testing — it eliminates some pellets.

But I wanted to try at least one more pellet, so I selected 7.9-grain Crosman Premier domes, simply because they’re often very accurate in spring guns.

I now knew the best hold for the rifle, so all I had to do was hold it as loosely as possible and let the pellets do the rest. Nine of the 10 pellets went into a nice group measuring 0.845 inches between centers. It was the first shot that opened it up to 1.596 inches.

Gamo Whisper Fusion IGT air rifle Premier Lite group 25 yards
Ten Crosman Premier Lites went into 1.596 inches at 25 yards, but 9 of them made a 0.845-inch group. I think the smaller group is representative of the true accuracy of the rifle with this pellet.

Final results
I find it interesting that the early shots were always thrown wide of the main group. By the time I arrived at the third pellet, I managed to keep the wide shots to 1 in 10. That tells me something. It tells me that the Gamo Whisper Fusion IGT is a rifle that has to be learned. Once you’ve done so, I believe that your groups will be about the same size as the smaller groups seen here.

I’m going to say something that may surprise some of you. I really like this air rifle a lot. I think it is too light and the trigger takes some getting used to, but in the end this is a great budget air rifle. It really isn’t that fussy, once you learn how to hold it the right way.

For some of you, even a used Beeman R9 is too expensive. I think you may want to look at the Whisper Fusion IGT. This is a gas-spring air rifle that has not gone overboard in the power department. It has a usable trigger, and it’s reasonably quiet and accurate. No, it isn’t as accurate as an R9, nor is the SAT as nice as a Rekord trigger; but for those who want to cap their outlay for an air rifle at $260 with a scope included, I think this is the one.

Walther LGV Olympia field test: Part 4

by Tom Gaylord, a.k.a. B.B. Pelletier

Part 1
Part 2
Part 3

by Tom Gaylord, a.k.a. B.B. Pelletier  <a href=
Walther LGV Olympia was a top-quality 10-meter target rifle in the 1970s.

The weather cooperated yesterday and gave me a perfect day at the range, so I was able to shoot the Walther LGV Olympia at 50 yards. I also shot the Talon SS with the 1:22″ twist barrel before the wind kicked up and stopped all airgun shooting, so I’m on the way to the final test of the different twist rates.

I knew the LGV Olympia was never going to hit the target no matter what I did to the rear sight, so I placed two 3-inch bulls on a 2×4 piece of target paper and used them for sighting. The shots landed far below these bulls, of course. How far is an eye-opener. I took a picture so you could see.

Walther LGV Olympia 50-yard groups
The pellets landed about 18 inches below the aim point at 50 yards. The sights had the pellets hitting the center of the target at 25 yards, so this is how far they drop in the second 25 yards. Notice that the center of the group of JSB Exact Jumbos on the right is about 2 inches lower than the center of the RWS Superdomes on the left.

I fully expected this to happen, so I stapled the bullseye targets to a huge piece of target paper so the pellet holes would show. Knowing they could well go to the same point, I used two separate bullseyes as aim points; and from the picture, you can see that was a good idea.

I selected the two best pellets from the 25-yard test for this. They were the JSB Exact Heavy, which was the best pellet at 25 yards, and the RWS Superdome that took second place.

I shot off a sandbag with the rifle rested on the flat of my hand in the classic artillery hold. The flight time of both pellets was extreme. Although I couldn’t see them in flight, the flight time told me they were dropping rapidly as they moved downrange.

JSB Exact Heavy
The first pellet I tried was the 10.34-grain JSB Exact Heavy. It’s by far too heavy for the LGV Olympia powerplant; but in the 25-yard test, 10 Exact Jumbos went into a group that measures 0.354 inches between centers. A novice might expect that, since the range was doubled, the group size would be as well. That would give us something like a 0.70-inch group for this pellet.

Walther LGV Olympia air rifle with JSB Exact Heavy pellets
The 50-yard group was larger than expected. Ten JSB Exact heavys went into 2.285 inches.

What I actually got was 2.285 inches between the centers of the two pellets that were farthest apart. That’s roughly 6 times larger than the 25-yard group and more than 3 times the expected size if you simply tried to extrapolate straight from 25 yards to 50 yards. This is why you have to be careful when making generalizations about accuracy.

The shooting conditions were perfect for this test. There was no breeze to speak of; and if I felt something, I always waited it out. I also had no shots that were called as anything but perfect. What you see here represents the best I was able to do with the LGV Olympia at 50 yards with this JSB pellet.

RWS Superdome
The second-best pellet at 25 yards was the RWS Superdome, which gave me a 10-shot group measuring 0.695 inches. Multiply that by 6, and you’ll get an anticipated group size of 4.17 inches. I’m doing that because of what happened with the JSB Exact Jumbos.

Walther LGV Olympia air rifle with RWS Superdome pellets
RWS Superdomes opened up even more than JSB Exact Jumbos. This group measures 3.062 inches between centers.

What Superdomes actually did was put 10 shots into 3.062 inches, so it was better than predicted (if you use the 6x predictor) but certainly much larger than simply double the 25-yard group size.

The lesson here is that group size does not simply increase linearly with distance. We hear that all the time. If a certain gun shoots 1-inch at 100 yards, we say it should shoot 2 inches at 200 yards. I’m saying that rarely happens. The group usually opens faster as the distance increases. Not always, but usually.

Evaluation
The Walther LGV Olympia is a remarkable airgun. Out to 25 yards, it’s extremely accurate, plus it’s very easy to cock and quiet to shoot.

Beyond 25 yards, though, the LGV Olympia quickly gets outside its comfort zone. There just isn’t enough power pushing the pellet to hold the group size to what you might expect.

These results are consistent with the results I got when shooting the FWB 300S at 50 yards. Installing a scope helped in that test, but only marginally. So, I’m not going to put a scope on this rifle. I’m satisfied and that’s as far as I’m going to test this rifle in a field setting.

Rifling twist-rate primer: Part 1

by Tom Gaylord, a.k.a. B.B. Pelletier

Recently, we have had a number of questions about rifling twist rates that were attached to the twist-rate report. These questions are extremely important to the understanding of how bullets and pellets are stabilized, so I’m starting a tutorial on rifling twists today. I’ll keep adding sections as I see the need to explain more about the topic.

Today, I want to lay a basic foundation of what the rifling twist rate does. Blog reader Feinwerk asked if centerfire rifles (he said higher-power firearm rifles) had different twist rates than rimfire rifles, and the answer is yes. I’ll get to that, but let me start at a time when things were much simpler.

Early firearms shot multiple projectiles, similar to today’s shotguns that shoot birdshot and buckshot, but much cruder. It wasn’t long before people started experimenting with single projectiles. They found that single projectiles retained more of their initial energy than many smaller projectiles, so they did more damage when they connected with a target. The problem was getting them to connect.

After much experimentation, people discovered that spherical projectiles were the best for firearms. They flew the straightest because they didn’t have the irregular surfaces that created low-pressure zones to guide the bullet astray.

Then, rifling was discovered. Straight rifling (straight lands running parallel to the axis of the bore) was first used as a means of holding all the unburned gunpowder residue, of which there was much. That allowed the gun to be fired more times before cleaning. And, at some point, someone cut the grooves in a spiral — to make them longer to hold even more residue? We’ll never know for sure.

Once people saw how much straighter a spinning ball flew compared to one that was not spun intentionally, the race was on. For hundreds of years, the spinning round ball was the only bullet that was known. It reached its zenith as the patched ball used in the American rifle we know as the Kentucky — where the rifling doesn’t even engrave the lead ball, but spins it by spinning a cloth or leather patch that holds the ball tight while it’s inside the barrel. The ball gets very little distortion from the barrel — although there is a pattern around its circumference where the rifling pressed against the patched ball.

When the patched ball exits the muzzle, the patch falls away and only the bullet travels on to the target. Accuracy increased with this system, and the loading time dropped because the shooter didn’t have to engrave the lead bullet with the rifling when he loaded the bullet/ball.

The conical bullet
Things never stand still, though, and after the patched ball came into general use shooters began experimenting with bullets that were not balls, but rather longer cylinders of lead. These were the first conical bullets.

ball and conical bullet
Although the round ball is very close to the same diameter as the conical bullet, it takes a lot more spin to stabilize the longer, heavier conical bullet.

A ball doesn’t need to spin very fast to be stable because its surface is smooth and regular. A conical bullet, on the other hand, is irregular — being longer than it is wide. Instead of a ball, it’s more like a spinning top that can balance only on its point as long as it spins fast enough. The longer the bullet, the faster it has to spin to remain pointed forward in flight. This attitude is called stability. If the bullet isn’t spun fast enough to remain point-forward, it’ll wobble like a top slowing down; and the varying air pressure that’s created will quickly cause it to tumble in flight. When that happens, the bullet will stray off its straight path.

Twist rate
This is when barrel makers began to be interested in the twist rates of their rifling. Prior to this time, they simply rifled the barrel with whatever twist rate their machinery supported. It’s a fact that the Hawken brothers rifled all their plains rifles with a 1:48″ twist, regardless of what caliber they happened to be.

With conicals, though, the twist rate does matter. Too slow and the bullet tumbles. Too fast and — well, less is known about what happens when the twist rate is too fast; but in my experience, you’re never able to get the same accuracy that you can when the twist rate is just right. A rifle that puts 10 shots into a half-inch with the right twist rate and bullet may put 10 of a different bullet that’s both lighter and shorter (and therefore both moving and spinning faster) into 1.5 inches.

The length of the barrel does not change the twist rate, nor its effect on the bullet — at least not directly. But a longer barrel sometimes does increase velocity. This is always true when black powder is used and can also be true when slower-burning smokeless powders are used.

A bullet that exits the bore of a barrel (of any length) with a 1:12″ twist rate and is traveling 1,200 f.p.s. is spinning at the rate of 1,200 revolutions per second (RPS). Speed that bullet up to 2,400 f.p.s. as it leaves the muzzle, and you increase the bullet’s spin to 2,400 RPS.

If a longer barrel causes an increase in muzzle velocity, it also causes an increase in the rotation rate of the bullet once it leaves the barrel. It does not change the barrel’s twist rate; but because the bullet is going faster; it’s also spinning faster. Reloaders take that into account when they load their cartridges. It’s possible to drive certain bullets too fast or too slow, resulting in less accuracy. Reloading is about finding a balance between the bullet and the velocity at which you launch it.

The M16
The most public and classic case of twist rates and their effects was the launch of the M16 rifle to the U.S. military. It addresses the specific question that Feinwerk asked. The early developers of the 5.56mm cartridge selected a twist rate of 1:14″ because the bullet was barely stable and would tumble and destroy flesh fast when it impacted a body. But they were focused only on the cartridge’s use in Vietnam — a conflict that was mostly conducted at short range and in very warm weather. The 1:14″ twist rate was too slow to stabilize the bullet properly beyond about 250 yards or in very cold weather. It worked great for a 40-grain .224-caliber bullet moving 4,000 f.p.s. from a .220 Swift, but was horrible when used with a 52-grain .224-caliber bullet moving 3,200 f.p.s from an M16.

Don’t confuse the caliber size in inches (.224″) with the name of the cartridge. Both the .220 Swift cartridge and the 5.56mm cartridge (M16) use the same .224″ bullets.

The twist rate for the M16 was increased to 1:12 inches, which worked better, but in time even that rate was discovered to be too slow to do everything the military wanted. Today, the twist rate for an M16 variant rifle runs anywhere from 1:7″ to 1:10″…depending on the specific model of gun, when it was made, which service owns it and what kind of ammunition it’s expected to shoot.

And the answer, Feinwerk, is yes…the twist rate of centerfire rifles does vary by caliber, by the bullets used and the velocities at which they’re driven.

This first twist-rate primer report was written at a very high level. I don’t know whether or not it addresses everything you wanted to know, so I’ll read your comments with interest. If we need to go into greater detail, that’s always possible. Otherwise, I’ll remain at this overview level in the next report.

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