Point of impact shift

[otis1016]

Evening everyone,

I was in my back yard this afternoon getting in a little practice with my Benjamin Trail and had an odd change in point of impact. 15.6 Gamo pellets, I was hitting 1/2” groups at 10 and 20 meters exactly at the point I was aiming for. All of a sudden POI shifted low and left at both distances, about an inch at 20, half inch or a little less at 10. I’ve used pellets from this tin in this rifle without any problem in the past. No loose screws, I didn’t drop the rifle or impact it in any way. The only adjustment I made at all was re-focusing the scope, no adjustment to windage or elevation. I noticed the problem immediately after the focus change. Could I have a scope failure? It’s original to the rifle since I’ve had it and has functioned perfectly. Could recoil have damaged it? The crosshairs don’t appear to have moved at all but I’ve never had this problem on a powder burner and wonder if this scope just isn’t robust enough for the rifle. Temperature was about 92, humid but no wind. Anything I should try before getting a new scope? Thanks.

Rick H.

 

[Hateful McNasty]

Well... If you had a coronagraph to check and kerp yrack of fps you can kinda determine if its the gun like piston seal or ram/ spring or breech seal ..

Now if a package scope ( scope sold on gun) they can be kinda iffy.. i think ove had 1 of 4 hold ..
I assume that gun did not have iron/ open sights to use to check .

About all you can do is rezero the scope and see how long thst lasts . Of you get another shift or wandering or having ng to chase zero could be the scope. The retical do have to "spin" for the evope to be bad. Overall a package scope tends not to be to great and lucky to last a few thousand shots.. heck lucky to last a tin of crosman nefore tattling loose inside.

These stronger is hard to keep a scope tight and true. A reason i never buy a gun that dont have sights . Scope only guns can keep a guy stranded.

 

[maxtrouble]

What happens after re-zeroing the scope? Does the point of impact change or wander again?

 

[Hateful McNasty]

If loose or bad it should. Like i daid you constantly chase zero. Like one i got you just can't zero . Then one will hold so many shots and like just jump off the hen one you can zero it set it down for a 1/2 hour like go get somthing to drink come back and its off again..lol just drifted off sitting still on its own ( my self adjusting scope)

Then loose stock, breech, mount, just movment of somthing..

Im supprised no more post here on this..

 

[cjtamu]

If it’s the CP scope that came with the kit it’s probably going to die at some point. The one that came with my Trail NP Elite did a few weeks ago. If everything else checks out, mount screws etc. are tight and gun is shooting properly and you either can’t get it to re-zero or it won’t hold zero it’s probably the scope.

Couple other things. When you say you “refocused” you mean the AO or you changed the magnification? The latter will shift POI but shouldn't be as much as yours has changed. Other thing is, when’s the last time you cleaned the barrel? When accuracy suddenly suffers for no apparent reason that’s the time for a good cleaning.

 

[ChuckHunter]

Another thing on those Crosman and Benjamin break barrels is that they have plastic barrel spacers at the breach...and will fail at some point especially if you shoot a lot!

 

[starlingassn]

on cheap scopes ive had the point of impact move when adjusting the focus (ocular adjustment for focusing the crosshairs,not the focus for the parallax)

 

[otis1016]

Thanks for all the input. I refocused the AO, not the magnification. I didn’t try and re-zero the gun because I wanted to rule out some possibilities without chasing my tail. This scope did come with the gun and I wouldn’t be surprised if it failed, it’s not a high end unit. I’ve not cleaned the barrel because it’s had fewer than 200 rounds fired and has been very consistent until now. I’ll take it out tomorrow and re-zero and see if it holds. I’ll also see if I can find a failure such as mentioned. I honestly don’t do any high volume shooting so this has been unexpected. Thanks.

Rick H.

 

[otis1016]

I just came in from firing about 20 rounds. I started with 1 shot at each distance and no adjustments with the same result. I took the focus adjustment back out and there was no change. I then adjusted windage and elevation and got back on target. After about three shots at each distance it went back to low and left with no further adjustments made. The group sizes are consistently under 1/2 inch at both distances using the same pellets from 2 days ago and temperature, humidity and wind are the same or very close which in the South means miserable. I am left thinking it’s definitely a scope issue of some kind. The only identifying marks are the name AR 22. I’ll find a decent mid-range scope and try it out. I’m not finding any other issue mentioned above like failed spacers. Oh well it wouldn’t be any fun without an occasional mystery.

Rick H.

 

[otis1016]

Well problem solved. I tried again today and it dawned on me that the only thing I didn’t check was the pellets. I got out a tin of round nose pellets about 1 gram heavier that I’ve used before without a problem. First shots were low but windage was good. I then went to the original Crosman red tip pellets and they were hitting half inch groups and then one would hit to the right, another left, high, low, no telling. Back to the heavier round nose and all is well. I think the rifle just doesn’t like the Crosman or else they are just all over the place on weight and size. I suspect it’s the former as my Maximus loves them. Next problem?

Rick H.

 

[1BadDart]

There is a reason quality pellets cost more.