well had her out to the range yesterday. shot a good group in unsupported prone position. after about 35rds it started jamming every 4 to 5 rounds. think it was just cause it was dirt dry and not yet broken in.....
Pull it apart, clean it, and lube it with good oil (Break Free CLP is a good one).
Run it again and if it still malfunctions, check mags, make sure buffer tube/spring is ok, check extractor, etc...
If it still malfunctions (and with a variety of mags), then you need to look at upgrading something