I have a Win 70 SA PF that is now 6TCU (formally 223Rem) that I was thinking of rebarreling to 20 PPC. I would want it to feed out of magazine and have tried it with couple of 22 & 6PPC rds and they seem to work with the magazine as is. Can the bolt face be opened up to PPC and the extracter changed or dose it need to be motified?