I am for the most part a bolt gun shooter. I do have a big bore AR ( Beowulf) and was looking to get a 5.56 upper to play with. I don't get junk but looking at the amount of CNC outfits putting out AR's it is leaving me scratching my head. I like the idea of the gas piston system on the Adams products so like the title says I am looking for user feedback OR suggestions on a company selling quality uppers that would hold up to everything comp. shooting could throw at it.....Pro's or con's on piston set-ups would be great as well.....Thank's for you time and input....A.T.