ArmaLite's great .50 caliber rifle has been refined, with smoother action, attractive bolt stop, and even greater strength than the original AR-50. The AR-50A1B is a single shot bolt action rifle chambered for the powerful 50 BMG cartridge and featuring a unique octagonal receiver bedded down into a V-shaped stock. Designed to be an economical answer for the challenge of long range shooting, the AR-50A1 is amazingly accurate and with its massive fluted muzzle brake, it has a very gentle recoil. It has a 30" chrome moly, 8 groove barrel with a RH 1:15" twist. The muzzle device has 1"-14 threading and is a highly efficient multi-flute recoil check for very moderate felt recoil. The upper features a modified octagonal form and is grilled and slotted for Mil-STD scope rail with Boss to engage cross-slot on receiver.This RA-50A1 has a triple front locking lug bolt, spring-loaded plunger, automatic ejection, Sako type extractor. The Schilen Standard Single Stage trigger has an approximate 5 lb. pull. It is accurate within 7"-8" @ 1000 yds. The 3 section stock has an extruded forend, machined grip with a vertical grip, and a forged and machined removable buttstock Shrinking the full overall Length of 58.5" to 49.75". The buttplate is vertically adjustable and specially built for heavy calibers. The AR-50A1 has a hard anodized aluminum and manganese phosphated steel black finish. Included with this rifle is a 15 Minute sight base.