A local gunsmith sets back the factory barrels on the 10/22 to achieve a bit less freebore, but does nothing else to the chamber. Claims the Ruger chamber is actually tapered. Does seem to improve accuracy. Of course any form of tight chamber in a .22 must take into account extraction. I've had problems with manual extraction in a 10/22 so modified, a loaded round sticking in the chamber when the extractor lets go before the round is extracted. It's a delicate balance.
Yep - I had seen that so when I rebarreled my 10/22 I chose one with a Bentz chamber. Those are dimensioned between the match and sporting chamberings specifically for autoloaders to avoid that problem. My Cooper and Anschutz .22's are match chambers and include a note not to shoot CCI stingers that are a little longer cased.
