Jerry is right about the chambers being the issue. Most factory barrels have a "loose" chamber to accomodate more ammunition varieties. The biggest ammo problem seems to be with Stingers because they have a longer shell casing. Bolt action .22s can take advantage of a tighter chamber for obvious reasons but most aftermarket barrels made for semi-autos seem to have a Bentz or Modified Bentz chamber. I dont know what the difference is in all of the different chamber configurations but I'm sure most reputable barrel makers can give you more info. Check out this link for more chamber info.
http://rimfirecentral.com/forums/sho...=match+chamber
As far as barrels go there are so many different options available that you need to know what it will be used for to make the best decision. Benchrest shooting, plinking, hunting, etc. Carbon fiber barrels are light and fast to point but not too stable for offhand shooting. Steel barrels are stable but not convenient for field carry. Factory contour barrels are great for hunting and carrying but not big on the "WOW" factor.
Decide what you want to use it for and go for it. I learned all of this because I bought first and asked later. I am still happy with my choice but I might have made a different choice if I had done more research.