I have two LaBelle and two Sanchez USGI magazines that I use with my RRA M4.  All 4 have green followers and function flawlessly but there is something that has been bothering me lately that I cannot figure out.

Both the LaBelle mags enter and exit the lower with ease.  But, the two Sanchez mags require some extra effort to get them in.  Now I am not talking about forcing them in with all my strength, just that it takes steady pressure to get them in.  I guess you would call them "tight-fitting"  Why is this?

At first, when I only had 1 Sanchez mag, I figured it was just differences in individual mags.  But now, after I got a second Sanchez from a different source, and it still has that issue, I am beginning to wonder.

In general, are Sanchez mags just wider than LaBelle mags?  Or is my situation just coincidence that both the Sanchez mags are tight-fitting?

Any information you guys can provide me with would be great!  Thanks!

Take a micrometer to the mags, and compare the tight ones with the not-so-tight ones.  Also, put a T-square to it also, some mags are kinda smushed, ie not square.  I've had some Sanchez mags that were like that, but 5 minutes with a c-clamp does it.  Go easy, though, because if you pop the welds, you are not gonna be happy.  

Ghost