My tac vest had a front pouch, with a flap, that would accommodate three 33 round silly sticks in it, and I kept another one, along with two 17 rounders in an old mag pouch, in the map pocket of the driver's door. The tac vest rode in the trunk and was worn when serving warrants. The mags in the door could be quickly grabbed and shoved in my pockets in an emergency when I exited the car. I never actually felt the need to ever do that, but I still have the same set up in my pickup today, even though I'm retired. I never carried supersize mags on my person doing day to day police stuff. The extra length would get in the way and catch on things, like seatbelts, would be my concern.