Gold Satin

Some Of The Latest AR Bolt Carriers

The technology of protecting metal surfaces has come a long way since the AR-15 was adopted by the US military. For reasons of institutional inertia, the military insist on sticking with phosphating as their method of metal protection. Phosphating gives a matte non-reflective surface and prevents corrosion, but it is not particularly abrasion resistant or self lubricating and it acts as a magnet to carbon and fouling. In the civilian arena other materials and coatings have taken off with the aim of reducing friction and the heat it causes, preventing corrosion, prolonging parts life, increasing reliability and making the direct impingement AR much easier to clean.

Fail Zero opted for an EXO surface treatment that resists wear 40% better than traditional chrome. It won’t peel, flake or rub off – nor will it gall. They assert that the Fail Zero AR bolt carrier group has been tested to 50,000 rounds with no lubricant and can be run devoid of the oil or grease to which sand and dirt stick, causing abrasion. The reduction in friction means a lot less heat which causes premature component failure. Shot peening is used to polish the surfaces to further reduce friction. The lack of lube, surface treatment and high polish mean carbon, unburned propelland and crud won’t stick to the bolt and carrier and can simply be brushed off.

JP Enterprises have a history of innovation in firearms design. With their  JP AR-15 bolt carrier they decided to make their carrier from stainless. It may seem strange, but by increasing the contact area by over 100%, they actually decreased friction significantly. The resulting JP AR bolt carrier is given a five step QRP process to give it very high lubricity and low friction. This results in a shiney black surface. This bolt is intended for real-world tactical applications where reliability is paramount and, although semiauto, has the wide military cocking pad.

DPMS are a huge maker of ARs and components and have the economy of scale to provide a wide range of alternatives. They market the DPMS AR-15 bolt carrier group in four different surface treatments - the usual phosphated/parkerized, traditional chrome, ion diamond and titanium nitride. Many think the military should have stuck with chromed carriers and bolts. It has good lubricity, great corrosion resistance, is relatively resistant to abrasion and best of all made the rifles easier to clean. The problem was it’s bright, shiny finish was not to the liking of the military. In this day and age, chrome is largely relegated to retro builds. Ion diamond coating is a molecure thick layer of carbone bonded to the steel. It’s cheaper than chrome and gives a military satin matte black finish. DPMS also offer Titanium Nitride or TiN. This surface has its issues as some users have had it eat components that aren’t hardened to the same level. This may account for the lack of popularity of this surface treatment

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