With Kimbers(or any 1911, I guess) I've had the best luck with Wilson Combat. They have nice smooth action due to the polymer follower. They are expensive but when I load one up I know I'll be able to count on it. My Kimbers seem to be pickier about mags than any other 1911s so far, go figure. Also good-the Kimber mags. Try the Kimber Tac-Mag-they will cost just about as much as a good aftermarket ones, but are all steel and say "Kimber" on the bottom, so they must be good...