My old low wall with a Stevens Pope barrel does that for two reasons. One is a short chamber that engraves the bullet in the rifling.  I had misfires because of that due to a headspace issue. A new (old) breechblock now fully seats the round but the rim recess is not deep enough and the block closing VERY slightly crushes the case.  It shoots so accurately that I am not making any changes. You can try coating a round with Dykem or magic marker to see where it is hitting, but i would see how well it shoots first.  There is some RWS short case ammo that is available. 

Jack

I don't have an answer to your question but I can say a few things that might help.

I have a CPA 22rf from 2009. Outstanding rifle. Very accurate. Gail told me they chamber 22's with a piloted reamer ground to the Winchester 52 spec.  So, do ALL CPA's have this chamber? Not sure.

Mine chambers match ammo like Eley and RWS tight and often it comes out hard after firing too. BUT, it does go in and come out and is accurate as anything.

You might call her if you think yours is unreasonably difficult.

Thanks folks you’ve given me the kind of direction I need. I’ll call CPA for some info and will certainly black my bullets for evidence of engraving which I’m sure there is, or hope so

My 22 cpa chambers the same.id have it no other way
I've shot my smallest 100 yard .22 LR groups of my life with this rifle.

My Cody Ballard is a Schoyen model with Badger barrel and match chamber. Much shooting results in a sore thumb from pushing the cartridges in. I still rely on the action to finish seating them, and they come out slightly easier. But I keep a90 degree needlenose plier handy to grab the cases to remove them.
It's an extremely accurate rifle, so I never cared to do anything to change the tight chamber.

Barrel is removed so no extractor interference. I just blacked three different brands of ammo and the bullets are certainly engraving and nicely. Since most rimfires don’t have a gradual ogive but a shoulder instead,  the lands leave pronounced grooves.  The more I look at this chamber the more I like it. Can’t wait to swap breach blocks and go shoot but it’s blowing like snot here in Western MI.

Have owned three Anschutz Rimfire and now two CPA .22 barrels. All chamber tight all very accurate.

One Anschutz a 1712 tight chamber gave me a fit Rimfire Silhouette. Would not shoot a 40 shot match & extract every case. Shot with a cleaning rod handy. May be accurate won’t extract you can’t shoot a match.

Sent it back to Anschutz gunsmith called me and said it extracted fine. Questioned he admitted he ran a few through it did not make a long run. Then blamed it on my ammo. Was using RWS R50 & told him what I thought of him the rifle. He polishes the chamber sends it back, still fails to extract, better not 100 % sold it shortly after.

Reason I relate the story tight chambers & accurate rifles often need some tweaking & it’s very much trial and error. Never had any problem with my CPA rifles but they are strong seaters & have adequate extractors. 22 bolt actions often very little extracting power. Even the best bolt Guns can give trouble with poor ammo. My Grandson was shooting my 1922M2 Springfield last week two had to be knocked out with a rod. Cheap ammo culprit.

Boats