Hmmm... I do believe that the original 8 rnd. Sig mags just had a cut down follower to allow the eighth round. Can anyone confirm this? Are there now (or where there) different springs from Sig for a 7 rnd. vs. an 8 rnd. magazine? If not, then the 8 rnd. magazine is probably over stressing the 7 rnd. mag spring, which would lead to shorter life, and more misfeeds... However, if a redesigned spring was made (not just the 7 rnd. spring with a coil cut off, that doesn't really solve the problem) then the 8 rnd. mag should probably work well...