I have been following CMMG’s progress with their .22LR AR22 line of hardware since the SIERRA was announced years ago. I bought the SIERRA and have been enjoying it since. By most reports the overall quality of CMMG products has improved in the last couple years. Perhaps I will order the MK4 HT and see how it compares to it’s older sibling SIERRA.
CMMG MK4 HT 22 AR15 UPPER RECEIVER – the CMMG MK4 HT dedicated .22 LR AR15 FLATTOP UPPER RECEIVER lets you do live-fire training with affordable rimfire ammo while retaining the weight, balance, and feel of your rifle. Replace your existing upper with the AR22, load the included Black Dog .22 LR magazine, and you’re ready to shoot. You practice with your existing trigger and fire control components, so the trigger pull feels the same. The mil-spec receiver has a standard MIL-STD 1913 Picatinny rail, charging handle, forward assist (non-functioning), and ejection port cover. Inside, the standard bolt/carrier assembly is replaced by a dedicated “bolt rail” of hardened tool steel with a blowback operated stainless steel bolt inside. Both components are built to run hard and handle the abuse of long practice sessions. M4 has the appearance and weight of a USGI M4 upper, with correct contour barrel, standard M4 handguard, A2-type flash hider, and a gas block/front sight tower with bayonet lug, sling loop, and square front sight post.
When modularity, accuracy and quality are all important, the Mk4 HT is the rifle of choice. The CMMG MK4 HT 22 AR15 UPPER RECEIVER features CMMG’s RKM11 KeyMod free float hand guard. Either a 416 stainless or nitrided 4140 CrMo steel barrels in a heavy taper profile are offered in 5.56mm and 300 BLK. The 22LR model is only available in the nitrided 4140 CrMo type barrel.
- Caliber: 22 Long Rifle
- Barrel: 16 inch 1:16 twist rate, heavy taper, 4140 CrMo, SBN
- Muzzle: thread protector, threaded 1/2-28
- Hand Guard: CMMG RKM11 KeyMod handguard
- Upper Rcvr: Forged 7075-T6 AL M4 type upper
- Trigger: Single stage mil-spec style trigger
- Weight: 7 lbs (unloaded)
- Length: 31 inches(stock collapsed)