Darthwhite8

I'd agree, stick to the M4 platform. Not exciting but you can adapt it into literally any role from a big pistol type abomination to a DMR, at the extremes. Plus parts are cheap, mags and pouches are cheap & plentiful, and it's one of the most popular platforms worldwide for a reason In that platform for a tinkerer I'd suggest ICS. Metal bodied, a split gearbox that's super easy to work on, and the hop unit is a high quality rotary design. £240ish for the base gun