Think I'll stick to paintball buffers - the 1/2 thread is a good size and connects to regular air fittings, besides that I can increase pressure as much as I want to as well, and at 850g I believe its not too heavy.

Been thinking of some way to increase pressure, say up to 16-20bar, but I cant find any compact 5/2 way valves rated above 10bar! Might try to design my own and give it a test, but its much more convenient finding something off the shelf!