Description
OTTER CREEK LABS POLONIUM SUPPRESSOR – DUTY-RATED 5.56 / 6MM RIFLE SILENCER, TUBELESS 17-4 STAINLESS, FULL-AUTO RATED
The Otter Creek Labs Polonium is a duty-rated 5.56 and 6mm suppressor built from H900 heat-treated 17-4 stainless steel in a tubeless design. It handles full-auto fire and high-volume shooting while weighing just 13.5 ounces. The 6mm bore covers 5.56/.223, 6 ARC, 6 Creedmoor, 6 Dasher, and .243 Winchester in a single can. At 5.8 inches long and 1.625 inches in diameter, the Polonium stays compact without sacrificing sound performance. Built-in internal and external flash hiders reduce visible signature for night vision and low-light use. The distinctive ribbed exterior cuts unnecessary material, increases surface area by 10%, and accelerates heat dissipation between strings of fire. HUB-compatible 1.375×24 rear threads give you access to virtually every QD system on the market. A 1/2×28 direct thread mount is included.
CAPITOL ARMORY’S OPINION
H900 heat-treated 17-4 stainless steel is the same material standard you see on much more expensive suppressors, and Otter Creek Labs built the Polonium around it from the start. The tubeless construction is not a cost-cutting measure. It is a more rigid, more durable design that handles the sustained heat of full-auto fire better than welded tube-and-baffle assemblies. For a duty-use or hard-use rifle suppressor, that matters. The ribbed exterior isn’t just for looks. The increased surface area speeds up cooling between strings, which directly affects how quickly you can run the gun again without cooking the suppressor. The integrated flash hiders front and rear are a nice addition for anyone running night vision.
The HUB mounting interface is the right standard to be on. Dead Air, SilencerCo, Q, YHM, Griffin Armament, Energetic Armament, and more all make QD systems for it. You aren’t locked into a single ecosystem. The included 1/2×28 direct thread mount gets you running out of the box, and you can add any HUB-compatible QD system later without replacing the suppressor. For a 5.56 and 6mm suppressor at this weight and length, the Polonium is a well-thought-out package.
FEATURES
- H900 heat-treated 17-4 stainless steel tubeless construction
- Full-auto rated
- 13.5 oz
- 5.8″ overall length, 1.625″ diameter
- 6mm bore. Compatible with 5.56/.223, 6 ARC, 6 Creedmoor, 6 Dasher, and .243 Win
- Built-in internal and external flash hiders for reduced visible signature
- Ribbed exterior increases surface area 10% for faster heat dissipation
- HUB-compatible 1.375×24 rear threads
- Black Cerakote finish
WHAT’S INCLUDED
- Otter Creek Labs Polonium 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
- Dead Air Key-Mo, Dead Air Xeno
- EA TBAC Adapter
- Griffin A2 Adapter
- YHM Kurz QD Adapter, Phantom QD Adapter
BARREL RESTRICTIONS
- 7.5″ minimum: 5.56/.223
- 10.5″ minimum: 6 ARC
- 12.5″ minimum: 6 Creedmoor, 6 Dasher, .243 Win
MEDIA
- PEW Science Test Results
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 I BUY?
Choose the Polonium (this model) 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
