Benjamin Prowler Large Group Size with vertical barrel movement

[30harry]

I have a new .22 BP and trying to get an idea of accuracy.  Not having any luck at all.  I bought one because a friend of mine bought one a few days ago and he is not able to make it shoot groups and I thought I would start investigating to see what I could find.  At first I shot it with the supplied CP scope and didn't like the results so put a UTG 3-12 x32 Bugbuster scope on it.  Still not there.  Groups are in the area of 7/8" at 18 yds with one flier pushing the group out to 3" or a vertical group of 2 1/4" with two shots at the top of the group, one shot in the middle of the group, and two shots at the bottom of the group. 

Now I will readily admit I have never shot a springer air gun or NP air gun before so I could be doing something wrong in trying to shoot it.  Holding too tight, too loose, who knows?  I can hold the scope on a 1/2" dot at 18 yards but the group is no where near 1/2" when finished with the five shots. 

Looking at the barrel mating to the action, I see vertical movement there.  With the gun either cocked or not, if I press down on the end of the barrel, it's like there is a "step" or click movement there. Using feeler gauges, I can press down on the barrel to the "step" let go of the barrel and a .013 gauge will fit in the gap between the barrel and the action.  Then if I pull up on the barrel (there isn't a noticeable "step" feeling of movement when I pull up on the barrel, like there is when I push down.)  a .005 gauge will barely fit between the barrel and the action.  So I believe the barrel is actually moving up and down a little bit.  As I said, this up/down movement occurs whether the gun is cocked or not.  So it seems to me as if any vertical movement of the barrel will cause your groups to be vertical also. 

Now I've been looking at the way the barrel locks up and I see the spring loaded pin (Alive Jam) with the ramp on it that is supposed to lock on the cross pin (Detent).  Pushing on the "alive jam", it doesn't seem to me as if there is very much pressure being exerted at all.  But I also don't see how there can be a "step/click" when I push down on the end of the barrel.  It seems like pushing down on the barrel would just cause the alive jam to ride up the detent and when you let go of the barrel, it should slide back down the detent back to the locked position.  Not stay at the point where a .013 feller gauge will fit between the barrel and action. 

So, finally getting back to the original problem.  Should there be any noticeable vertical movement on the barrel when you push down on it?   Is there a noticeable difference in the gap between the barrel and the action if you press down on your barrel or pull up on it.  I'm not talking serious stressing it either.  Just a gentle downward press and you can feel the click/step movement. 

Assuming this is normal operation, what other things could I be doing wrong to cause these vertical groups?  I've tightened the stock and action screws and the scope mount screws and the problem is still there.  I've only tried two brands of pellets.  The Crosman Premier HP 14.3 and the Ruger Superpoint 1.2g pellets.  I'm trying to find some RWS locally but that's proving difficult. 

Any assistance would be greatly appreciated. 

Harry

[Roadworthy]

If you've not done so, clean the barrel.  No, this won't hold the barrel in place but it will improve your groups.

Does the barrel move relative to the rest of the action?  Or is it possible your stock screws are a bit loose?  Pay special attention to the rearmost one, accessed through the trigger guard.  Be sure you're on the screw and don't slip - that hard plastic trigger guard can break.  PVC cement does work and the Benjamin Regal trigger guard is metal and a perfect fit.  (Guess how I know.)

If the movement is indeed between the barrel and the action my suggestion is return it on warranty.  You'll save yourself a lot of headaches.  If you have put an aftermarket trigger into the gun, put the stock trigger back.  Crosman won't fix the gun and return it, they'll send you a new one.

[30harry]

The movement is definitely between the barrel and the action.  All screws are tight.  The front stock screws were rather loose when I took it out of the box but I tightened them down.  I'll check with Crosman and see how to go about returning it. 

I cleaned it using the RWS push through cloth pellets.  It took several before they started coming out clean. 

Thanks,

Harry