I've had an LCP II for a couple of weeks now and have put over 200 rounds through it... It feeds all my ammo EXCEPT Sig (both defense and target). I get failure-to-extract problems with both. The odd thing, I thought, was that it works perfectly with PMC, Ruger ARX, Blazer brass, and Herters. Well, I think I figured it out - the Sig ammo has a flat point and none of the others do. The magazines in the new LCP II sit about 1mm too high, allowing the top round in the magazine to block the extraction of a spent cartridge (at least with my pistol) for the first couple of rounds. I have no problems if I only load 4, btw... The magazine seats so high that the rounds barely even touch the feed ramp! I called Ruger and they are sending me a new mag, but my confidence is low - I suspect all the mags are like this... Moral of the story (at least for me): don't shoot flat-point ammo, which includes wide hollow-points. Since my ammo of choice is ARX, it's not a big deal, but I do think it is a design flaw.