Mcx rattler 300blk sbr bk 5″#., Rmcx-300b-5b-tap-sbr | 30+1., Caliber: 300 AAC Blackout, Barrel: 5.5″, Capacity: 30+1, Finish: Black, Sights: Optics Ready, StockFrameGrips: Collapsible / Folding Stock Skeletonized Folding Stock, Magazine: 1 30 rd. Lancer Magazine