Olympic Arms UM-1 Ultramatch AR-15, 20" Heavy Stainless (Black Matte) Barrel Receiver Material: 7075 T6 Aluminum Forged Receivers Machined By Olympic Arms Receiver Finish: Black Matte Anodized Receivers, Parkerized Steel Parts Action: Gas Operated Semi-automatic Action Upper Type: Flat top w/ picatinny rails Front Sight: Gas block w/ picatinny rails Handguard: Free floating aluminum tube w/ knurled surface Barrel: 20" bull Ultramatch, broach-cut, 416 stainless steel Chambering: .223 Remington Bore: Long-life non-chromed bore Twist Rate: 1x10 Muzzle: Crown Stock: A2 w/ trapdoor Length: 38.125" Weight: 8.76 lbs Included: AC4 Pneumatic Buffer: Originally designed for military use, this recoil buffer replaces the standard recoil spring buffer found in AR15 rifles. This buffer is air-charged and tested to extremes without failure. Because its air-charged there are no messy leaks commonly found in similar hydraulic products which have historically failed over time. Widely used for CMP and hi-power rifles because the AC4 reduces felt recoil and muzzle climb providing reliability during matches. It also takes away the "twang" sound of the original buffer spring. (I will include the original spring and tube with the sale.) Original Case and manual Hogue Grip 1x 20 round magazines (straight version) 2x 5 round magazines 1" Scope Rings Rifle has been fired 40 times. This was broken in properly, cleaning after each round for the first 20 rounds, then after each 5. I have two AR's and need the money for my .308 project. $1100 or partial trade. The ONLY trades I will consider at this time will be a Savage 10PC or Remington 700 SPS Tactical in .308win.