Archive for May 2011
RWS Diana model 54 recoilless rifle: Part 3
by B.B. Pelletier

The RWS Diana 54 recoilless air rifle, also called the Air King, is big, beautiful, powerful and accurate.
Today, we’ll test the RWS Diana model 54 Air King for accuracy. Before I show you the targets, however, let me mention a couple of things.
Some observations
First, I shot this rifle for today’s test rested directly on a sandbag. There was no artillery hold. As I mentioned in the earlier reports, the Air King anti-recoil system acts like an artillery hold and is able to do so perfectly. There’s no reason to rest this gun on the palm of your hand. That’s not because the rifle is recoilless, but rather because of how the rifle handles recoil.
In the 54, the action slides in the stock when the gun fires. It always slides the same distance and always contacts the same points within the stock, so the system acts like a perfect artillery hold. A rifle having a different anti-recoil system like the Giss contra-piston system, for example, doesn’t work the same way and does need to be held in the artillery hold for best accuracy; but those guns that use the sledge system — like this one and a few FWB target rifles — do not.
Next I want to comment on the trigger. The one I’m testing is a T05 and very nice. It has a positive two-stage pull with a crisp second-stage let-off. It does have a plastic trigger blade, but that isn’t important because it isn’t one of the wearing parts within the trigger assembly. Everything that wears is steel and properly hardened.
The one detractor of this trigger is that the blade is too curved. A straighter blade would feel better. I am going to test the new T06 trigger soon, and I’m going to scrutinize it closely because it has a long way to go to be better than the T05.
Finally, I used a prototype UTG scope base with a lot of built-in droop to mount the CenterPoint 3-9×40AO scope on the test rifle, and it STILL shot low. So, a lot of droop is still present in Diana guns, and it still needs to be addressed with a drooper mount. I did find that the UTG base sped up the scope-mounting process, turning a half-hour job into a 10-minute task. The scope I used is an older one and doesn’t have the illuminated reticle of the scope I linked to here.
The UTG scope base does raise the scope quite high, but the high comb on the 54 was able to elevate my face to the exit pupil. I could have easily used a scope with a 56mm objective lens and still had clearance for the scope over the spring tube.
Accuracy
Because I am still recovering from a hernia operation, I shot only a single 10-shot group with each pellet tested. Ten-shot groups really require a lot of cocking, and this sidelever isn’t the easiest gun to cock. The distance was 25 yards, and all groups contain 10 shots.
The first pellet I tested was the venerable 14.3-grain Crosman Premier, which is well-known as one of the best for this .22 caliber rifle. They fit the breech easily but were not loose. And the gun buzzed a lot when firing them.

Nine of the ten pellets made a group measuring 0.518 inches between centers. But pellet six strayed outside this neat little hole to enlarge the group to 0.929 inches between centers. It wasn’t a called flyer, it just went outside the group for no reason I can explain.
After the Premiers, I loaded 10 JSB Exact 15.8-grain domes, which are often even better than Premiers in some airguns.

Ten JSB Exact 15.8-grain domes made this group, which measures 0.613 inches between centers.
Finally, I tried some Predator Polymag pellets that everyone likes to use for hunting. They fit the 54 breech very tight, but went in without a lot of forcing. They expand well on small game and are especially effective in .22 caliber.

Ten JSB Predator Polymag pellets made this 0.975-inch group at 25 yards.
Well, there you have it. I think if I were to shoot additional groups of Premiers, most 10-shot groups would look like that first 9-shot group. Because I didn’t season the bore with each new pellet, I think I would have gotten slightly better groups if I had.
Ten shots into a half-inch at 25 yards is not to be sneezed at, though I really thought I would do better. I was thinking I could get half-inch groups out at 35 yards from this rifle. It might still be possible, but I think I’ve demonstrated that the 54 is an air rifle to be reckoned with.
UZI CO2 BB Submachine Gun from Cybergun: Part 2
by B.B. Pelletier

Cybergun brings us this Mini Uzi BB submachine gun.
This gun’s last report had lots of good comments from owners and from those who have been researching it. I think the most powerful feature it has is the fact that it fires from the open bolt. When you shoot, a heavy mass reciprocates in mock recoil. It’s the difference between an M3 grease gun that jumps all over the place when it fires and an HK MP5 that barely recoils at all. This Mini UZI CO2 BB Submachine Gun by Cybergun really jumps around.
I can see why people are impressed by its performance in full-auto. It feels so realistic with that heavy steel bolt working back and forth on every shot.
With the open bolt comes an open receiver, also just like the grease gun. When the gun’s ready to fire, the receiver looks menacingly open and ready for action.

This gun is open for business!
Accuracy is another feature we have yet to test, but everyone who owns the gun praises it for its accuracy. We’ll find out.
Charge the magazine and load
The 12-gram CO2 cartridge fits into the stick magazine, small end first. Don’t forget to put some Crosman Pellgunoil on the tip of each new cartridge before you pierce it. That will be blown through the valve, where it gets on every sealing surface and keeps the gun sealed against gas loss. With it, your gun should last for years. Without it, you may have an early failure.
The BBs are loaded one at a time, with the spring-loaded follower held down with the other hand. It isn’t the easiest thing to do, but it works. I found I could load 26 BBs, despite the manual stating that it holds 25.
Gas consumption
Most owners understand that a CO2 gun at this power level will get about 50 shots per cartridge. I tested for this and found that it does get 50 shots, but the last ones are not as fast as the average shots from the first magazine.
Velocity
They advertise this gun at 344 f.p.s. I tested it with Daisy zinc-plated BBs, which I have found in the past to be the largest and most uniform BB Pyramyd Air carries. In other words, they’re always the fastest. In the test gun, they averaged 350 f.p.s. for 10 shots. The velocity range went from 345 to 357 f.p.s. I was pausing about 10 seconds between each shot for this test, and the temperature was 71 degrees F.
I tested how much velocity is lost by firing very fast. We know that cooling a CO2 gun causes it to shoot slower, and the CO2 is what cools the gun. The faster you shoot each shot, the faster the gun cools down and slows down. To test this, I fired 12 quick shots as fast as I could pull the trigger, then chronographed the next shot. It went 313 f.p.s. That should tell you guys who modify the gun to shoot full-auto what’s going to happen. As you hold down the trigger, you’re going to lose velocity to the tune of about 40 f.p.s. That’s not such a great loss and I think you won’t really notice it.
Gas consumption
Another thing I wanted to test was the overall gas consumption. Other owners said they’re getting about two magazines per CO2 cartridge, which would be 50 shots. That sounds about right, given that the gas also has to operate that heavy bolt. I chronographed shot No. 49 at 283 f.p.s. Shot 50 went 269 f.p.s. Because I was able to get 26 BBs in the magazine, I also got shots 51 and 52. Shot 51 was lost, but shot 52 went 231 f.p.s. The gun is definitely out of gas at that point, though the bolt still comes all the way back. To load more BBs and attempt to get a few extra shots is just asking for a jammed BB in the barrel.
Handling
I’d forgotten that the gun has a grip safety but was reminded when I started shooting it. Also, it didn’t register that I had to cock the bolt for the first shot. Since we had a question about how you can see the sights with that fat knob in the way (the cocking knob), I’m showing it here, so you can see the wide slot cut through the center.

Here is how you sight through the cocking knob.
Rating so far
It’s difficult to remember the other BB submachine guns at this point in time, but I think I can safely say this one has the most realistic feeling recoil. That heavy bolt really rocks the gun when it moves. I do like the grip safety, and even the trigger seems pretty crisp and positive for this type of BB gun. Although there are a few plastic parts on the outside of the gun, this is a very heavy airgun that gives a solid sense when you shoot it. If it’s as accurate as the owners say, it’ll be a winner in my book.
Why do shot groups move?
by B.B. Pelletier
I couldn’t fit the entire question into the title, so here it is:
Why do shot groups move from side to side when the scope setting doesn’t change?
This question does not include different pellets impacting at different places on a target at the same range, which is caused by the individual flight pattern of each type of pellet. However, I’ll address that question before moving on with the first one.
Today’s question was suggested by Jay in VA, who really wants to know why different pellets or bullets shoot to different places, with respect to left and right. Jay, that’s caused by how each pellet or bullet is stabilized. Back around the turn of the 20th century, Dr. F. W. Mann conducted an experiment in which he locked a barreled action in a 3,000-lb. vice (his “Shooting Gibralter” rest, a concrete pier sunk 40 inches below ground level and extending about 30 inches above, and fitted with a cast iron lockdown rifle rest) and then fired the “gun” at 100 yards in still air. After each shot, Dr. Mann rotated the barreled action 90 degrees, until he had shot it in a complete rotation. His lockdown mount was constructed to allow this rotation, so the barrel was never unlocked from the rest.
The barrel was locked down and could not move except to rotate along the axis of the bore. Still, it shot to four distinct places, each separate from the other. One was when the barrel was straight up, the next was with the barrel rotated 90 degrees to the right, the next was rotated 180 degrees to the right and the last was rotated 270 degrees to the right. That gave four distinctly different points of impact at 100 yards. Some Pope barrels shot groups smaller than an inch this way, but other barrels with less pedigree produced four-shot groups as large as 16 inches.
So, if the SAME barrel shooting the SAME bullets shoots to four distinctly different places, depending on how the barrel is rotated on its axis, how do you think it will do when different bullets are used? That’s right, different points of impact. It has to do with the projectile’s rotational stability and the bullets finding their own path (trajectory) once they’re free of the confining restraint of the barrel. We might like to think that bullets travel along a precise path, but it isn’t always true. Sometimes, they have to diverge to the path that’s dictated by their own inherent stability. Archers know this more than riflemen, because arrows have their own independent flight rules and the experienced archer learns what each arrow wants to do.
The real question
But that isn’t the question I want to address today. I want to talk about this: When a scope is sighted in at one distance, it will shoot to the left or right of the point of aim at a different distance. There are two main reasons for this.
Unstable flight
The first reason for this is the fact that some pellets spiral in flight. In other words, as they travel downrange they don’t remain on a straight line; rather, they travel in a spiral that goes in the same direction as the spin introduced by the rifling. A righthand-twist barrel can produce a pellet that flies with a right-hand spiral. You don’t have to take my word for this, you can watch it for yourself on You Tube. The man who made and narrates that video calls the spiral a wobble, but we’re talking about the same thing. He found it was caused by a dirty bore, but I’ve seen the same thing through the scope when using certain pellets that were not suited to a particular barrel. Clean or dirty barrels aside, those pellets always spiraled.
The video shows a pellet losing stability and spiraling from that loss, but a pellet can also be inherently unstable and always spiral. When that happens, the pellet will group at different points around the point of aim, depending on the distance the gun is from the target.
You don’t need a high-speed camera to see this. How do you tell if you have this problem? Simple, shoot three groups at three different ranges. Make the sight-in range the first target and the other two farther away. If they look like the ones shown here, your pellets are spiraling.

Gun sighted-in at 25 yards. Pellets are centered.

Same gun with same sight setting but shooting at 20 yards.

Same gun and same sight setting but at 30 yards. This pellet is spiraling.
Scope misalignment
A more fundamental cause of groups moving from left to right is caused by a slight scope misalignment, in relation to the bore. If the bore is pointed at 360 degrees and the optical axis of the scope is pointed at 5 degrees (that would be 5 degrees to the right of where the barrel is pointed), the shooter will adjust the reticle to bring together the point of impact and point of aim. Let’s say he does this at 25 yards, where the pellet hits the point of aim. If the scope is misaligned as I am describing, then at 20 yards it’ll group to the right of the point of aim, and at 30 yards it’ll group to the left of the point of aim. Where it hits depends on how the scope is misaligned, of course.

At 25 yards, the gun hits the point of aim.

At 20 yards, the pellet strikes low and to the right.

At 30 yards, the pellets strike high and to the left.
This type of “scope shift” will always go in the same direction. The farther out you shoot, the more to the left the groups will be; the closer you shoot, the more they’ll move to the right. They’ll always maintain this right-to-left relationship and will never reverse directions. That’s a diagnostic you can use if and when such a problem arises.
While the above two sets of targets look similar, they were created by two very different effects. In the first set, the pellet’s moving in a righthand spiral that’s increasing in size as the pellet moves farther from the muzzle. In the second set of targets, the pellets are shifting from the low right to a high left position and will keep moving in a straight line away from the aim point (to the left) as the distance to the target increases.

A spiraling pellet moves from one side of the target to the other and back again as the range increases.

A pellet shift caused by scope alignment always moves in the same direction — in this example, right to left.
Pellet shift diagnosis
Here’s how you figure out what the problem is.
Are the pellets moving from side to side and back again as the range increases? That’s a spiraling problem, and the dispersion (distance from the aim point) increases with the distance. The solution is to use different pellets or perhaps to clean the bore.
Are the pellets shifting in one direction and only as the range increases? That is a scope alignment problem, and the scope needs to be realigned to correct it.
Don’t be discouraged
This problem confounds shooters all the time, and it’s often the root cause of a misdiagnosed scope shift problem. Don’t be discouraged after reading this report. You can mount a scope accurately enough that you will never encounter this kind of problem.
Knowing that gives you power over these two common problems. If you know they exist, you can watch for them and make corrections when necessary.
Crosman Outdsoorsman 2250XE: Part 1
by B.B. Pelletier
Today, we’ll start a look at an unusual airgun from Crosman. It’s getting to be summer around the country, and the summer guns are CO2 guns, so today’s choice of the Crosman Outdsoorsman 2250XE is just in time. This .22 caliber CO2 carbine wouldn’t exist if Crosman hadn’t reinvented itself at the beginning of the 21st century.
Dennis Quackenbush and I sat on both sides of Crosman’s former president and CEO during the Airgun Breakfast at the NRA Annual Meetings in Kansas City, back in May 2001. We were all chatting about the airgun business, and I happened to mention that Dennis made a good living making and selling upgrades and accessories to what was at that time a $39 Crosman CO2 pistol. The executive was surprised, thinking that no one would want to spend money on such a cheap airgun, but Dennis floored him when he said, “You sell them the gun for $39 and then I sell them $125 worth of accessories for it.” From his facial expression, I don’t think he really believed me.
Fast-forward a few years, and Ken D’Arcy took over the top spots at Crosman. It took him a few years to get his new house in order, and then the Crosman Custom Shop was created. To make a very long and encouraging story short, today’s airgun is a direct benefit of that move. Crosman no longer pursues just the high-volume discount-store sales anymore. They also keep their corporate eye on the ball by making and selling guns for hardcore airgunners. Today’s offering is just one example.
Basically, the Outdoorsman 2250XE is a descendant of Crosman’s classic 2240 .22 caliber, single-shot pistol. But look at what they’ve done with it! It’s so prettied-up that it’s sometimes hard to see the family resemblance.
The 2250 XE is also a single-shot, bolt-action .22 rifle that’s powered by a single 12-gram CO2 cartridge. But this gun is different in so many ways. First, because it has an 18-inch barrel instead of just a 10-inch barrel, you get optimum performance from each CO2 cartridge. Airgun hobbyists who modify Crosman pistols know that an increase in barrel length gives the CO2 gas longer to push on the pellet and produces higher velocity. However, there’s a point of diminishing returns, which happens to be somewhere around 16 and 18 inches of barrel. After that, the pellet looses some velocity from friction. So, the barrel length on this carbine is anything but an afterthought!
Grand opening
Edith knows what I think of airgun marketing. I believe that the moment the box opens the customer forms an opinion of the gun inside. Pack a beautiful airgun in a cheap, flimsy cardboard box and you cheapen the customer’s first impression of his or her new airgun. On the other hand, if the packaging is superior, it conveys a sense of pride that attaches to the customer in an instant. Top car salesman all know this, as do successful realtors. Why don’t more airgun manufacturers?
Well, Crosman is one company that knows what first impressions are all about. When I opened the box of the test rifle, Edith told me she thought I ought to show you what we saw. So, here it goes.

The box has eggcrate foam protecting the gun, scope, mounts and ancillary things. It’s a sturdy container that you can use to store the gun, as the foam is closed-cell.
I’ve seen many hundreds of new airguns come from their boxes in my time, but this one was too tempting not to pick up immediately. Once in my hands, it invited a check of the trigger-pull after establishing it was unloaded and not charged.
This carbine feels very small in my hand, though the 14-1/4-inch pull length is adult in every way. Perhaps it’s the light 3.6 lbs. of weight that seems to float in your hand. I remember once owning another CO2 carbine like this that seemed just as nice and compact. The Sharp UD carbine I had years ago was a nice little shooter that’s extremely hard to find these days, and it felt just like this 2250 XE.
Trigger-pull
While holding the carbine, I couldn’t resist trying the trigger a couple times and was surprised by the best factory trigger I’ve ever felt in a Crosman pistol on this frame. Don’t misunderstand me, now, because I’m not comparing this single-stage trigger to the new Marauder pistol trigger, which is stupendous. This one isn’t as nice as that, but with the installed trigger shoe, I found the release nice and pleasant. More on that in Part 2.

The trigger shoe really helps with the trigger-pull!
Another nicety I noticed was the 6-inch steel breech with 11mm dovetails cut into the top. You get a scope with the carbine, so you’re expected to shoot it that way, but those who refer a peep sight will like the fact that Crosman also supplies a post front sight. I’ll scope the rifle for the accuracy test.

Yes, that’s a steel breech that will accept a scope mount or a peep sight.

Want open sights? Crosman provides this front post that won’t get in the way if you use a scope.
Stock
You cannot overlook the outrageous skeleton stock. Carved out of beech, it adds very little weight to the rifle, yet brings your sighting eye up high to intercept the exit pupil of the scope. I can’t wait to try it!

Put it all together, and it’s a beautiful gun!
Performance
The rated velocity for this carbine is 550 f.p.s., but I expect it to go a bit faster than that — especially with lighter lead pellets. I’d be surprised if RWS Hobbys didn’t get up close to 600 f.p.s. That 18-inch barrel is not to be ignored.
What do YOU expect?
Let’s be honest. This is a $270 CO2 airgun that started life as a far less expensive model and got modified to this high price point. I want to know what to expect from a gun like this. I’ve already compared it to a rare Sharp carbine that you can’t buy used for less than $600, but that isn’t going to satisfy most people, especially those who aren’t collectors. I want to know what performance you think a gun like this should have.














