On the other hand

I remove the barrel from my 25 caliber impact nickname Annie, cleaned it cleaned out the Shroud and the barrel assembliy put three o rings on my Barrel liner it had none secured with painters tape.

Now my groups are half what they were at 50 yards basically p9ellet in pellet all touching at least . so apparently the O-rings have something to do, I guess with harmonics. The way I understand it but it did make a difference