i think how you hold the gun will have greater effect than an o ring... the slug takes a long time to exit the barrel compaired to rifles. so what happens after the shot has a big impact on where the bullet will hit. In the picture the bullet to the far right was off the bench the group of 4 is when i held the gun as I would in my stand. When I fired from a bench my shoulder was in such a position that prevented the gun from moving straight back under recoil, the barrel actually moves up and to the right...in the group of 4 i'm sitting more upright so the recoil of the gun actually pushes me back allowing the gun to follow ..allowing the bullet time to get out of the barrel while it's still on target.. - hope this helps..btw i have the O-Ring in all of my H&R guns...I don't think they hurt preformance..also I shot 300gr sst's in this pic- Kevin