I'm building my second Mega Arms MATEN and I love the plateform. Yes a quality trigger is a must and any "AR15" trigger will work. I've used Jewel, Jard, Gessiele, timney and CMC. I have fouind the CMC trigger works best for me because it is a "Drop in" trigger. Most barrels in the DPMS 308 plateform rifles are 1X10 twist so the 175 gr and above bullets work. Both of my MATENs are in 1X12 twist and they love the 168 SMK loaded to M852 Specs.
Hoped this helped and not hendered like some people do. And to help him out the 308 was built by Stoner first and then the 223. The charging handle was in the carry handle groove.