New – Otter Creek Labs Polonium K chambered for 5.56mm
- Caliber: 5.56 NATO, .223 Remington, 6mm/.243 (6 ARC, 6mm Creedmoor, 6mm Dasher, .243 Winchester)
- Length: 4.8 inches
- Weight: 11.5 oz (without mount)
- Outer diameter: 1.625 inches
- Bore diameter: 6mm
- Material: H900 heat-treated 17-4 stainless steel
- Construction: CNC welded tubeless design
- Rear thread: 1.375×24 (HUB standard)
- Minimum barrel length: 7.5″ for 5.56/.223 and 7.62×39
- Full-auto rated: Yes
- Belt-fed rated: Yes, on 16″ 5.56 belt-fed machine guns. Do not exceed 300-round string without cool down.
- Flash hider: Integrated internal and external
- Warranty: Lifetime, no BS







