I bought a grip plug for my Glock and it is one of the plastic one's that will hold a few small item's. It will hold batteries, or 1 round. I have an extra round in it right now. Te question is this, would this be illegal? I know we are restricted to 10 round mags, but in a round about way this ups the gun carrying capacity to 11 or 12 if you have 1 in the chamber.