Its a sig mosquito and its never been accurate from day 1BowerR64,
On that .22: make sure the bore isn't leaded up. Sometimes a good brushing will restore the accuracy. Also check to see that the chambers line up with the barrel perfectly. Reaming the forcing cone can help if the chambers don't exactly line up. As you suspect, if the cylinder mouths are smaller than the ore diameter it isn't gonna shoot either.
Ill look at it again i think i put more time into it after that image but look at the big chuck that was taken out of the crown on the first image. The bottom one cleaned up that big chunk I dont care what the rest of the barrel looks like the crown edge is what i wanted to clean up. Those chatter marks im not so worried about.Only revolvers. The semi auto has the chamber cut into the barrel.
Your crown doesn't look like it's fixed in the picture. A good polishing of it will help. Brownells sells a polishing kit I believe.
d-a
Hard to tell if the crown is concentric from powder residue on the muzzle. Heeled bullets would add to the difficulty as well.
Did your POI change? Or just group size?
d-a
Just a reminder that this isn't the proper forum to discuss them new-fangled firearms.