Availability: In Stock
Current Stock: Out of stock
The Alexander Arms UST17 17 HMR complete upper assembly brings specialized rimfire power to your AR-15 platform. Built on a dedicated 17 HMR upper receiver, this precision-engineered system swaps onto a standard AR-15 lower, letting you add a dedicated varmint and small-game upper to your existing rifle without replacing the whole gun. The 18-inch straight-flute barrel is optimized for the 17 HMR cartridge with a 1:9 twist rate and sports a 1/2-28 RH threaded muzzle capped with an A2 flash hider.
This upper runs a blowback operating system — no bolt carrier group or charging handle swap needed — and features a LAR Alexander Arms-branded M-LOK handguard finished in black anodized aluminum. The upper assembly itself weighs 4.5 pounds, keeping your rifle nimble for long days in the field. Two 10-round magazines come included, giving you ready-to-shoot capacity out of the box.
Whether you're serious about prairie dog control, hunting ground squirrels, or just want a tack-driving rimfire platform with AR ergonomics, this 17 HMR upper delivers accuracy and reliability in a modular package. The 17 HMR's flat trajectory and minimal recoil make it ideal for precision shooting at distance, and the dedicated upper means you're not compromising the setup of a centerfire rifle to get there.
| Cartridge | 17 HMR |
| Barrel Length | 18 inches |
| Barrel Profile | Straight flute |
| Twist Rate | 1:9 |
| Muzzle Threading | 1/2-28 RH |
| Muzzle Device | A2 flash hider |
| Operating System | Blowback |
| Handguard | LAR Alexander Arms M-LOK |
| Receiver Finish | Black anodized |
| Upper Weight | 4.5 pounds |
| Magazines Included | Two 10-round |
Yes. This is a dedicated upper assembly that attaches to any standard AR-15 lower receiver. You'll use the same lower pin set and buffer system as any other upper.
We don't have pricing data on ammunition, but the 17 HMR is a premium rimfire cartridge. Your best bet is to check current ammo availability and pricing at retailers before committing to the upper.
The complete upper assembly, two 10-round magazines, and a standard charging handle. You'll need to supply your own AR-15 lower receiver, bolt carrier group, and buffer system.
The barrel is threaded 1/2-28 RH, which is standard for 17 HMR and many rimfire accessories. Any suppressor or brake rated for 17 HMR and 1/2-28 threading will work, but verify compatibility with your chosen device before purchase.
SKU: 115677202 • Weight: 6.8oz
Availability: In Stock
Current Stock: Out of stock
The Alexander Arms UST17 17 HMR complete upper assembly brings specialized rimfire power to your AR-15 platform. Built on a dedicated 17 HMR upper receiver, this precision-engineered system swaps onto a standard AR-15 lower, letting you add a dedicated varmint and small-game upper to your existing rifle without replacing the whole gun. The 18-inch straight-flute barrel is optimized for the 17 HMR cartridge with a 1:9 twist rate and sports a 1/2-28 RH threaded muzzle capped with an A2 flash hider.
This upper runs a blowback operating system — no bolt carrier group or charging handle swap needed — and features a LAR Alexander Arms-branded M-LOK handguard finished in black anodized aluminum. The upper assembly itself weighs 4.5 pounds, keeping your rifle nimble for long days in the field. Two 10-round magazines come included, giving you ready-to-shoot capacity out of the box.
Whether you're serious about prairie dog control, hunting ground squirrels, or just want a tack-driving rimfire platform with AR ergonomics, this 17 HMR upper delivers accuracy and reliability in a modular package. The 17 HMR's flat trajectory and minimal recoil make it ideal for precision shooting at distance, and the dedicated upper means you're not compromising the setup of a centerfire rifle to get there.
| Cartridge | 17 HMR |
| Barrel Length | 18 inches |
| Barrel Profile | Straight flute |
| Twist Rate | 1:9 |
| Muzzle Threading | 1/2-28 RH |
| Muzzle Device | A2 flash hider |
| Operating System | Blowback |
| Handguard | LAR Alexander Arms M-LOK |
| Receiver Finish | Black anodized |
| Upper Weight | 4.5 pounds |
| Magazines Included | Two 10-round |
Yes. This is a dedicated upper assembly that attaches to any standard AR-15 lower receiver. You'll use the same lower pin set and buffer system as any other upper.
We don't have pricing data on ammunition, but the 17 HMR is a premium rimfire cartridge. Your best bet is to check current ammo availability and pricing at retailers before committing to the upper.
The complete upper assembly, two 10-round magazines, and a standard charging handle. You'll need to supply your own AR-15 lower receiver, bolt carrier group, and buffer system.
The barrel is threaded 1/2-28 RH, which is standard for 17 HMR and many rimfire accessories. Any suppressor or brake rated for 17 HMR and 1/2-28 threading will work, but verify compatibility with your chosen device before purchase.
SKU: 115677202 • Weight: 6.8oz