A month or so ago a Marlin 39AS followed me home. Its a nice shooter, but appears to have a rather strange problem that's got me puzzled...
My primary reason for buying a lever gun was the ability to use a variety of .22 ammo such as CB's, shorts and other subsonic rounds for short range pest control. Obviously I wouldn't expect these to shoot to the same POI as high velocity .22LR, but what I've noticed is a very pronounced diagonal striping that's heavily dependent on projectile velocity. Lower speed ammo shoots low and left, while higher speed stuff shoots high and right. The effect is very pronounced, with as much as a 3" horizontal shift when comparing CCI Green Tag (low left) with Federal 510 (high right). Its also not just limited to those ammo types - I've seen similar results with Rem Target, SK Std+, Fed Bulk, Fed Automatch etc, etc.
The only explanation I can come up with is that the projectile must be taking a helical path in flight. My question is why, and is there anything I can do about it?
My primary reason for buying a lever gun was the ability to use a variety of .22 ammo such as CB's, shorts and other subsonic rounds for short range pest control. Obviously I wouldn't expect these to shoot to the same POI as high velocity .22LR, but what I've noticed is a very pronounced diagonal striping that's heavily dependent on projectile velocity. Lower speed ammo shoots low and left, while higher speed stuff shoots high and right. The effect is very pronounced, with as much as a 3" horizontal shift when comparing CCI Green Tag (low left) with Federal 510 (high right). Its also not just limited to those ammo types - I've seen similar results with Rem Target, SK Std+, Fed Bulk, Fed Automatch etc, etc.
The only explanation I can come up with is that the projectile must be taking a helical path in flight. My question is why, and is there anything I can do about it?
