This!
Dont be suprised when most 1911 issues are caused by the mag. Anytime I have a problem with a 1911, I always check the failure against a quality mag. Of course, learning that this is that first place to check has been a costly lesson for me as once upon a time I would go through the major components leaving the "try a better mag" for last, only to find the failure went away with the original parts and a good mag.
+ a Bazillion
The 1 failure for 1911's is crappy mags. It's funny people spend big money tricking out a 1911 only to think it's ok to use a $10 mag that's out of tolerance.
Make sure you use a high quality mag. I like Chip McCormick's myself, lot's of folks prefer wilson, any of the big names should do you right. I like mags that have a non-tilt follower, but that feature usuallly costs a round, becuase the follower has to have extra material on the underneath (spring) side.