AR-9 4.5" Complete Upper Receiver Build Kit - 4.25" M-LOK Handguard
This Complete Upper Build kit is comprised of the following items and comes with everything that you need to complete an upper.
| Barrel | Specifications |
|---|---|
| Caliber | 9mm |
| Length | 4.5 |
| Material | 4150 Chrome Moly Vanadium |
| Profile | Straight |
| Finish | QPQ Corrosion Resistant |
| Gas System Length | None |
| Gas Block Journal | N/A |
| Dimpled? | No |
| Twist Rate | 1:10 |
| Muzzle Thread | 1/2x36 TPI |
| Weight | 8.3oz |
| Barrel Extension | Integrated |
| Target Crown | 11 Degree |



