Hunting Forum

For fun & plinking, I have a Crosman M4-177. With the iron sights, I am knocking out 1" groups at about 10 yards. When I mounted 2 different scopes which I know were shooting straight, I am shooting low and wide left even after adjusting windage & elevation. Any practical advice would help. The groups are still tight, but I can't seem to get the scopes dialed in. I even tried shooting left handed to see if that would change anything, no dice.

Any thoughts?

Your scope mounts are not in line with your barrel. You've run out of adjustment in the scope.

That's a common problem with air rifles due to the constant play between the rifle and barrel. ( if it's a breaking pump ) If two different scopes are doing the same, I would say it's the barrel being misaligned with the rifle. Swap it for another rifle. My crossman 880 does the same, but it's is only inconsistent high and low.


Ok, I went back and checked some reviews on your gun.  Even though it's a "fixed" barrel, which is a good thing, it is known for poor sighting with a scope due to the way it mounts and lots of plastic parts on the gun leading up to it.  May want to stick with the iron sights?  Have you tried pellets?  It shows much better accuracy with them. Cool looking gun though, just a lower end grade.  Have fun!

Thank you Grandpops and GLW. I will check into those this weekend and see if there's any change.

I had a similar problem with my old Winchester pump, accurate as can be with the iron sights, but big groups when I put a scope on. My dad and I discovered that there was play in the barrel which wasn't a problem with the iron sights as they were on the barrel, the scope, however was on the receiver. We shimmed the barrel to take the play out and the glass got accurate.