.358 Winchester AR-10 Upper Assemblies

About .358 Winchester AR-10 Uppers

Moriarti Armaments builds .358 Winchester AR-10 upper assemblies in Miami for large-frame, DPMS-compatible lowers. Our current model is the 12.5" Claw pistol upper with a 416R stainless barrel, 1:12 twist and a 12" M-LOK handguard. .358 Winchester is the .308 Winchester case necked up to a .358" bullet, so it hits hard with heavy bullets at short to medium hunting ranges.

What is the difference between .358 Winchester and .308 Winchester?

.358 Winchester and .308 Winchester share the same parent case but use different bullet diameters: about .358" versus .308". The larger, heavier bullet gives .358 Winchester a different ballistic and hunting profile. Both run in the same large-frame AR platform, but you need the correct .358 Winchester barrel and ammunition.

Does a .358 Winchester AR-10 upper use a .308 BCG and magazines?

Yes. .358 Winchester is a .308 Winchester case necked up to .358, so it runs a standard .308 bolt carrier group and .308 AR-10 magazines. Only the barrel and ammunition are different. Read .308 Win vs .358 Win: key differences for a side-by-side comparison.

Related: all AR-10 upper assemblies