Availability: In Stock
Current Stock: Out of stock
The CMMG AR-15 Resolute 100 Mk4 22LR upper receiver assembly is a no-fuss way to convert your existing AR-15 lower into a dedicated .22 LR trainer or small-game rig. Built on CMMG's proven Mk4 platform, this 17" upper pairs a 4140CM steel barrel with a billet 6061 T6 aluminum receiver and ships complete with bolt carrier group, charging handle, and muzzle brake—no additional gunsmithing required. It's the kind of upgrade that pays for itself through cheaper ammo consumption, reduced recoil, and instant familiarity for shooters who want to build marksmanship without burning premium centerfire rounds.
The 17" barrel runs a traditional blowback operating system and 1:16 twist, optimized for standard .22 LR velocities. The CMMG EML15 M-LOK handguard gives you a modern, modular rail platform for lights, lasers, or other accessories—no picatinny-only limitations. Threading is 1/2 x 28, so your brake accepts common .22 suppressors if you want to run it sound-suppressed. Everything arrives pre-assembled and zeroed, meaning you can mount it to your lower and go to work; no barrel headspacing questions or function testing required.
At 4.0 lbs and 25" overall length, this upper is lightweight enough for casual backyard sessions but rigid enough for precise rifle work. CMMG's Cerakote finish standard means it'll handle field use without rust worry. This is the smart AR-15 owner's answer to "I want a dedicated .22 trainer that doesn't require a whole new rifle." Feed it with CMMG's .22 LR conversion magazines, and you're ready for plinking, small-game hunting, or low-recoil practice on your existing lower.
| Brand | CMMG |
| Model | Resolute 100 Mk4 |
| Caliber | .22 LR |
| Barrel Length | 17" |
| Barrel Twist | 1:16 |
| Barrel Material | 4140CM Steel |
| Barrel Contour | MT |
| Operating System | Traditional Blowback |
| Upper Receiver | Billet 6061 T6 Aluminum |
| Handguard | CMMG EML15 M-LOK |
| Muzzle Device | CMMG ZEROED Muzzle Brake |
| Muzzle Thread | 1/2 x 28 |
| Charging Handle | CMMG ZEROED Ambi |
| Dust Cover | ZEROED AR15 Polymer |
| Finish | Cerakote Standard |
| Weight | 4.0 lbs |
| Overall Length | 25" |
| Compatibility | Standard AR-15 lower receivers |
Yes. The CMMG Mk4 .22 LR upper is designed to function with any standard AR-15 lower receiver. You'll need CMMG's .22 LR conversion magazines to feed it.
The upper assembly ships complete with bolt carrier group, CMMG ZEROED ambi charging handle, ZEROED polymer dust cover, and ZEROED muzzle brake. Everything comes pre-assembled and zeroed, so you can mount it straight to your lower and shoot.
The muzzle is threaded 1/2 x 28, the standard for .22 LR suppressors. You can swap the included muzzle brake for a suppressor or use an adapter, depending on your preferences.
Yes. The Resolute 100 Mk4 is designed for plinking, training, and small-game hunting. The 17" barrel and .22 LR cartridge make it well-suited to varmint and small-game applications where .22 LR is appropriate.
SKU: 115802134 • Weight: 4.73oz
Availability: In Stock
Current Stock: Out of stock
The CMMG AR-15 Resolute 100 Mk4 22LR upper receiver assembly is a no-fuss way to convert your existing AR-15 lower into a dedicated .22 LR trainer or small-game rig. Built on CMMG's proven Mk4 platform, this 17" upper pairs a 4140CM steel barrel with a billet 6061 T6 aluminum receiver and ships complete with bolt carrier group, charging handle, and muzzle brake—no additional gunsmithing required. It's the kind of upgrade that pays for itself through cheaper ammo consumption, reduced recoil, and instant familiarity for shooters who want to build marksmanship without burning premium centerfire rounds.
The 17" barrel runs a traditional blowback operating system and 1:16 twist, optimized for standard .22 LR velocities. The CMMG EML15 M-LOK handguard gives you a modern, modular rail platform for lights, lasers, or other accessories—no picatinny-only limitations. Threading is 1/2 x 28, so your brake accepts common .22 suppressors if you want to run it sound-suppressed. Everything arrives pre-assembled and zeroed, meaning you can mount it to your lower and go to work; no barrel headspacing questions or function testing required.
At 4.0 lbs and 25" overall length, this upper is lightweight enough for casual backyard sessions but rigid enough for precise rifle work. CMMG's Cerakote finish standard means it'll handle field use without rust worry. This is the smart AR-15 owner's answer to "I want a dedicated .22 trainer that doesn't require a whole new rifle." Feed it with CMMG's .22 LR conversion magazines, and you're ready for plinking, small-game hunting, or low-recoil practice on your existing lower.
| Brand | CMMG |
| Model | Resolute 100 Mk4 |
| Caliber | .22 LR |
| Barrel Length | 17" |
| Barrel Twist | 1:16 |
| Barrel Material | 4140CM Steel |
| Barrel Contour | MT |
| Operating System | Traditional Blowback |
| Upper Receiver | Billet 6061 T6 Aluminum |
| Handguard | CMMG EML15 M-LOK |
| Muzzle Device | CMMG ZEROED Muzzle Brake |
| Muzzle Thread | 1/2 x 28 |
| Charging Handle | CMMG ZEROED Ambi |
| Dust Cover | ZEROED AR15 Polymer |
| Finish | Cerakote Standard |
| Weight | 4.0 lbs |
| Overall Length | 25" |
| Compatibility | Standard AR-15 lower receivers |
Yes. The CMMG Mk4 .22 LR upper is designed to function with any standard AR-15 lower receiver. You'll need CMMG's .22 LR conversion magazines to feed it.
The upper assembly ships complete with bolt carrier group, CMMG ZEROED ambi charging handle, ZEROED polymer dust cover, and ZEROED muzzle brake. Everything comes pre-assembled and zeroed, so you can mount it straight to your lower and shoot.
The muzzle is threaded 1/2 x 28, the standard for .22 LR suppressors. You can swap the included muzzle brake for a suppressor or use an adapter, depending on your preferences.
Yes. The Resolute 100 Mk4 is designed for plinking, training, and small-game hunting. The 17" barrel and .22 LR cartridge make it well-suited to varmint and small-game applications where .22 LR is appropriate.
SKU: 115802134 • Weight: 4.73oz