A.R.M.S. #22 Medium 30mm Scope Rings — The Clone-Correct Choice for Mk12 Mod 0 Builds
The A.R.M.S. #22 Medium rings are the scope mounting solution specified for the Mk12 Mod 0 Special Purpose Rifle. If you are building a correct Mk12 Mod 0 with a Leupold Mark 4 TS30-A2 on a PRI upper, these are the rings — not an alternative, not a substitute. A.R.M.S. (Atlantic Research Marketing Systems) manufactured these under contract for the U.S. military's SPR program, and the medium height positions the scope centerline at the correct height for cheek weld on an A2-style stock or PRI fixed stock.
Engineering and Construction
Each ring is machined from a single piece of 7075-T6 aluminum and hard-coat anodized to mil-spec. The throw-lever system is A.R.M.S.' signature — a single lever locks the ring to any MIL-STD-1913 Picatinny rail and returns to zero when remounted. This is not just a convenience feature; it was a requirement for the SPR program, where operators needed the ability to remove optics for transport or malfunction and remount without re-zeroing. The 30mm tube diameter accommodates the Leupold Mark 4, Nightforce NXS 2.5-10x24, and most other 30mm scope bodies used in SPR-pattern rifles.
Medium vs. High — Which Height?
Medium height is correct for Mk12 Mod 0 builds with a flat-top upper receiver and standard A2 or PRI stock. If you are running an optic with a larger objective bell (40mm+) or using a riser, the A.R.M.S. #22 High rings may be required to clear the rail. For a standard Mk12 Mod 0 with a Leupold TS30-A2 (36mm objective), medium is the correct specification.
Complete Your Mk12 Mod 0
→ A.R.M.S. #22 TRC Tactical Ring Cap
→ A.R.M.S. #22 TRR Tactical Ring Rail for Mk12
→ A.R.M.S. #41 Folding Front Sight for Mk12
CCC stocks the full A.R.M.S. catalog for Mk12 and SPR builds. If you need help matching ring height to your optic and rail configuration, reach out — we have been building Mk12s since 2017.
