Description
OTTER CREEK LABS POLONIUM K SUPPRESSOR – COMPACT 5.56 SILENCER, 6MM BORE, TUBELESS, HUB/BRAVO 1.375X24
The Otter Creek Labs Polonium K is a compact 5.56 suppressor built from H900 heat-treated 17-4 stainless steel in a tubeless, CNC-welded design. At 4.8 inches and 11.5 ounces without mount, it adds minimal length and weight while delivering full-size suppression performance. The 6mm bore covers 5.56 NATO, .223 Remington, 6mm ARC, 6 Creedmoor, 6 Dasher, and .243 Winchester. Full-auto rated and built to handle sustained fire on short-barreled hosts like the MK18, the Polonium K also features integrated internal and external flash hiders to reduce visual signature for night vision and low-light use. The HUB/Bravo 1.375×24 rear thread pattern provides access to virtually every popular QD mounting system on the market, and a 1/2×28 direct thread mount is included.
CAPITOL ARMORY’S OPINION
K cans aren’t the quietest silencers available, and there’s an understood trade-off when it comes to using a smaller can. The Polonium K isn’t as quiet as the full-size Polonium, but it holds its own in sound suppression. The tubeless design allows for more internal volume than many competing cans. With a smaller volume, most compact silencers have noticeably more muzzle flash. The Polonium K uses an integrated internal flash-hiding design. This greatly reduces the visual signature when shooting in low-light conditions. The HUB mounting pattern also allows for nearly any desired direct thread or QD solution to be utilized, giving shooters the ability to set up the can how they want, rather than how the manufacturer thinks it should be. If you want a compact, well-rounded silencer that comes in at a great price point, the Polonium K is highly recommended.
FEATURES
- 4.8″ length without mount
- 1.625″ diameter
- 11.5 oz without mount
- H900 heat-treated 17-4 stainless steel
- Tubeless CNC-welded construction
- 6mm bore – rated for 5.56 NATO, .223 Rem, 6mm ARC, 6 Creedmoor, 6 Dasher, .243 Win
- HUB/Bravo 1.375×24 rear threads
- Integrated internal and external flash hiders
- Full-auto rated
- 7.5″ minimum barrel length (5.56 NATO)
WHAT’S INCLUDED
- Polonium K suppressor
- 1/2×28 direct thread mount
- Tube clamp for mount installation
COMPATIBILITY
- HUB Direct Thread Mounts: Dead Air, SilencerCo, Energetic Armament, YHM
- SilencerCo Bravo ASR
- Plan-B by Q (Bravo / Omega)
- Dead Air Key-Mo (Bravo / Omega), Xeno
- EA TBAC Adapter
- Any other HUB-compatible solution
COMPARE THE POLONIUM LINEUP
Otter Creek Labs builds three versions of the Polonium to fit different needs. All share the same H900 heat-treated 17-4 stainless steel construction, tubeless design, and 1.375×24 HUB mount compatibility.
Polonium K (4.8″ / 11.5 oz) – The compact option. Choose this when overall length and weight matter more than maximum sound reduction. Same 6mm bore as the standard Polonium, same barrel length requirements.
Polonium (5.8″ / 13.5 oz) – The balanced option. One inch longer than the K delivers noticeably better sound performance while keeping the 6mm bore for dedicated 5.56 and 6mm cartridge suppression.
Polonium 30 (5.8″ / 13.5 oz) – The multi-caliber option. Same size as the standard Polonium but with a 7.62mm bore. Handles everything from 5.56 NATO through 300 RUM and 300 Norma Magnum. Trade-off: slightly less 5.56 suppression than the dedicated 6mm bore models.
| Polonium K | Polonium | Polonium 30 | |
|---|---|---|---|
| Length | 4.8″ | 5.8″ | 5.8″ |
| Weight | 11.5 oz | 13.5 oz | 13.5 oz |
| Diameter | 1.625″ | 1.625″ | 1.625″ |
| Bore | 6mm | 6mm | 7.62mm |
| Max Caliber | .243 Win | .243 Win | 300 Norma |
| Min Barrel (5.56) | 7.5″ | 7.5″ | 7.5″ |
| Included Mount | 1/2×28 | 1/2×28 | 5/8×24 |
| Mount Threads | 1.375×24 HUB | 1.375×24 HUB | 1.375×24 HUB |
| Full-Auto | Yes | Yes | Yes |
WHICH POLONIUM SHOULD YOU BUY?
Choose the Polonium if:
- You shoot primarily 5.56/.223 or 6mm cartridges
- You want the best 5.56 suppression in the lineup
- You don’t need .30 caliber compatibility
- One inch of additional length over the K is acceptable
Choose the Polonium K if:
- Minimal added length is your priority
- You’re running a short-barreled rifle and every inch counts
- Weight savings of 2 oz matters for your application
- You’re willing to trade some suppression for compactness
Choose the Polonium 30 if:
- You want one suppressor for multiple rifles in different calibers
- You shoot .308, 6.5 Creedmoor, 300 Win Mag, or larger
- Multi-caliber flexibility outweighs maximum 5.56 performance
- You own rifles in both 5.56 and .30 caliber platforms
All three models share the same HUB mount compatibility, so your muzzle devices and QD systems work across the entire Polonium lineup.
