I have recently purchased a .22lr rifle with a moderator (and scope) from a local RFD.
I went to zero on Sunday morning, started off to zero with the mod on - this resulted in rather erratic and confusing shot placement, it looked like the rounds (Using CCI sub sonic Hollow points) were as far as I can guess were tumbling and hitting my target area side on leaving a slot rather than a hole.
After a bit of confusion (not done too much zeroing myself) I removed the mod and zero'd with the bare rifle, this gave me nice round holes with good grouping. Refitted the mod to try and confirm my suspicions which were confirmed by erratic grouping and slot holes again.
The rifle is a Ruger 10/22 Carbine (wood stock) with fold down iron sights, moderator is an A Tec Wave and scope Hawke Vantage 4x42 (iirc).
I suspect that the moderator is not sitting concentric on the barrel possibly due to it catching on the very end of the iron sight, damage to the moderator or damage to the threading on the barrel.
My thoughts are to find a friend with a .22 that is has the same thread as my mod to try the moderator on to try and rule the threading on the rifle out. As with it potentially catching on the iron sight or the threading on the barrel it is possible that just by replacing the mod with a new one I will still have the same issues.
Is this the best route to go or what are peoples suggestions?