I have a super duper AR chambered in 50 Beowulf. It has the flat top receiver with 16" barrel (no threading), gas block. I just had the feed ramp polished by BlackHeart International. The buffer spring, ejector spring and extractor spring have all been upgraded to Tubb's CS Flat Springs. I also have the ST-T2 Heavy Buffer. It has the adjustible stock with recoil pad. It will also come with 4 mags. 2 Brownell steel mags and 2 Pmags. It has a decent Bushnell 3x9x40 scope with a NEW Bushnell holosights mounted over it. The gun only has 20 rounds down the pipe. I just added an ambi sling adapter over the end plate and a one point braided paracord sling. I will also throw in 4 boxes of (20) new ammo. I will post pics up shortly. The lower is a Spikes Multi, with ambi safety and the upgraded springs i listed. It also has the forward assist and dust cover. Palmetto State Armory LPK. Asking $1600 shipped or will trade for a 1911 OEV or M1 or ????