BigGreenMachine
Regular
- Location
- Newfoundland
Just got a new lower and want to install a 9mm upper on it. Wondering if the mags have to be pinned to 5 rounds or can I use 10 round pistol mags? Also what brand do I go for 1000-1200? Rock River Arms is what I'm thinking. Glock mags would be a nice feature. Any advice or recommendations?


















































