6mm AR

• Name — 6mm AR • Origin — United States • Type — Centerfire rifle • Designer — Robert Whitley • Parent — 6.5 Grendel • Case Type — Rimless, bottleneck • Bullet —.243 • Neck —.271 • Shoulder —.4323 • Base —.4433 • Rim Dia —.4449 • Rim Thick —.0591 • Case Length — 1.525 • Length — 2.260 • Case Capacity — 36 • Rifling — 1-8" • Primer — Small rifle • Bw1 — 105 • Btype1 — Berger VLD • Vel1 — 2750 • En1 — 1763 • Balsrc — http: www.6mmbr.com/gunweek068.html The 6mm AR / 6x38mm AR is an intermediate centerfire wildcat cartridge initially designed by Robert Whitley for long-range performance in an AR-15 rifle.

This variant uses an Ackley Improved fire formed case with less tapering and a 40-degree higher shoulder permitting a larger powder capacity. It is claimed by its maker to be capable of driving a or heavier grain projectile at (satisfying the "6mm Optimum").

These wildcats also push forward the shoulder of the same necked Grendel case similar to the Turbo 40, yielding more powder capacity. or heavier grain VLD boat-tail bullets have to be seated deeply within the case neck, however, rendering some of these volume gains illusory but there is an increase in volume even with the longer bullets nonetheless.

Similar to the 6mm Turbo 40 and 6mm FatRat, the 6mm Grinch has a blown-forward shoulder on par with the 6mm Dasher to eke maximum powder capacity from the necked Grendel case.