I've just got a quick stupid question that I'm about 99% sure I know the answer to. I have a Sig P220 .45 which came standard with 8 round mags. I recently bought a couple of 10 round extended mags, like the ones that come on the P220 Combat, but a firearms 'expert' I know told me that they were illegal since they were extended. If it's not over 10 rounds, it's kosher, right?