Proof Research 300 BLK AR Type Steel Barrel

Proof Research 300 BLK AR Type Steel Barrel have set the standard for what a 300 BLK Barrel should be. The steel barrels are made in house with the exact same commitment to quality and repeatability as they employ on carbon fiber barrels. The drilling, rifling, and lapping process is identical to their composite barrels.  They start with the same steel used in the carbon fiber barrels.  It is a double stress-relieved 416R stainless steel, a pre-hardened chromium stainless steel that was specifically designed by engineers in collaboration with rifle barrel makers to provide the consistent, high quality and durability the firearms industry demands.

Proof Research 300 BLK AR Type Steel Barrel Features

Excellent machinability for gun drilling and reaming, plus exceptional polishability for uniform lapping

A homogeneous microstructure which responds to heat treatment providing a uniform hardness along the length of the barrel

An optimum combination of high tensile strength along with requisite toughness to withstand extreme chamber pressures encountered during firing

Excellent erosion wear characteristics and corrosion resistance

Product Registration »


Type Part Number Barrel Length Twist Rate Gas System Length Gas Journal Diameter Muzzle Thread Weight
PR15 100530 12.5” 7 Pistol .750 5/8-24 1 lb 8 oz
PR15 100578 16” 8 Carbine .750 5/8-24 2 lbs 4 oz

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Additional information

Weight N/A
Barrel Length

12.5" 100530, 16" 100578


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