hkm4

Centerfire? oh boy. i'm assuming you mean higher caliber like .223 or 5.56? they actually sell an M4 with this caliber but you can't have a removable magazine - so the gun comes with the magazine slot blocked off permanently - you load the bullets from the top i think. your other option if you want to use a 10 rd removable magazine in those caliber is a non pistol grip rifle - which looks so ugly. that's my understand of the law here. :(

Yes California - the land of 10 rd magazines! :( I'm getting my Umarex M4 next week so I look forward to long years of enjoyment from my rifle and this community!