White Oak Armament 18" Rifle SPR Barrel

White Oak Armament built its name on SPR-pattern barrels, and the company's 18-inch SPR is the standalone barrel most directly tied to the Special Purpose Rifle lineage. The 416 stainless match contour and .223 Wylde chamber give an MK12-style precision build the half-MOA potential that the original SPR program demanded, while the Wylde chamber feeds both .223 Remington and 5.56 NATO without compromise.

The rifle-length gas system matches the canonical MK12 SPR and gives the smoothest cycling on an 18-inch gun, lowering bolt-carrier velocity for sustained precision strings. The 1:7 twist stabilizes the heavy 75 to 77 grain match projectiles, like the Black Hills MK262 77gr OTM, that an SPR build is meant to shoot. The .750-inch gas journal accepts standard low-profile and adjustable gas blocks, and the 1/2x28 muzzle threads take any common flash hider, brake, or suppressor mount.

This is the barrel for a builder cloning the SPR look and capability from parts rather than buying the complete Daniel Defense MK12 upper. The issued MK12 wore Douglas and Krieger barrels, so the White Oak is the practical modern SPR-profile equivalent rather than an exact-period reproduction. It ships as a bare barrel: budget for a gas block, rifle-length gas tube, and a free-float handguard to finish the upper. White Oak also catalogs mid-length and fluted 18-inch SPR variants directly for builders chasing a specific gas length or weight target.