Otter Creek Labs Polonium

What mounting system does the Polonium use?

The Polonium uses the industry-standard 1.375x24 HUB rear thread interface. It ships with a 1/2x28 direct thread adapter included in the box, but the HUB pattern opens the door to virtually every popular quick-detach mounting system on the market. That means you can run the Rearden Atlas, Dead Air KeyMo, SilencerCo ASR, Q Plan B, YHM SRX, and other popular HUB-compatible mounts without any hassle. All three models in the Polonium lineup — the standard Polonium, the Polonium K, and the Polonium 30 — share the same HUB thread pattern, so your muzzle devices and QD systems work across the entire family.

Will it work well on my AR-15?

Absolutely. The Polonium was purpose-built for the AR-15 platform. It's a dedicated 5.56 suppressor with a 6mm bore, optimized specifically to get the most out of 5.56 NATO and .223 Remington. The full-auto rating means it can handle anything an AR-15 can dish out from mag dumps on a duty build to sustained strings on a select-fire. It also covers the growing 6mm cartridge family, including 6 ARC, 6 Creedmoor, 6 Dasher, and .243 Winchester, so if you've got a 6mm AR build in the safe it's already covered. The minimum barrel length for 5.56/.223 is 10.3 inches, which means it plays nicely with everything from an MK18-length SBR up through a full-length rifle. One note: OCL discourages the use of pronged flash hiders like the Dead Air 3-prong or SOLGW NOX on barrels shorter than 12.5 inches, as pronged devices accelerate wear on any suppressor. It's a recommendation, not a hard restriction, but worth keeping in mind on shorter builds.

How does it compare to the Polonium K?

The Polonium K is essentially a shortened version of the standard Polonium. The same steel, same design philosophy, same HUB mount interface, just one inch shorter and two ounces lighter. The K clocks in at 4.8 inches and 11.5 ounces without a mount, while the standard Polonium runs 5.8 inches and 13.5 ounces. That extra inch of internal volume on the standard model translates to noticeably better sound performance. The K is the right pick when overall package length is a priority. Think MK18 builds, tight spaces, or setups where you want to keep the total length in check. The standard Polonium is the better call when you want every decibel of suppression the platform can deliver. Both are full-auto rated, both cover the same calibers, and both carry the same lifetime warranty. Neither is a bad choice. It really comes down to whether length or sound performance is your bigger concern.

Is it flow-through?

No. The Polonium is a sealed, CNC-welded tubeless design. It is not a flow-through suppressor. The entire internal structure is welded together as a single unit from H900 heat-treated 17-4 stainless steel. That construction is what allows it to be full-auto rated and belt-fed certified, and it's a big part of why the Polonium punches so hard on sound performance for its size and price. The trade-off is that it is not user-serviceable. You won't be disassembling the baffle stack for a deep clean, but cleaning isn't necessary for rifle cans for most users.

What barrel lengths are OK to use?

Otter Creek Labs publishes specific minimum barrel length requirements for the Polonium series, and they apply to both the standard Polonium and the Polonium K. For 5.56/.223, the minimum is 10.3 inches. For 6 ARC, it's 11.5 inches. For 6 Creedmoor, 6 Dasher, .243 Winchester, and other 6mm cartridges, the minimum is 14.5 inches. One important point worth repeating: the 5.56 Polonium and Polonium K have a 6mm bore. You cannot shoot 6.5mm or 7.62mm projectiles through them. If you want a single can that handles .308, .300 BLK, or magnum calibers, that's what the Polonium 30 is for.

Does Otter Creek Labs have a good warranty?

Yes. OCL backs the entire Polonium lineup with a no-nonsense lifetime warranty. The Polonium, Polonium K, and Polonium 30 are all covered. Otter Creek Labs has built a reputation for being straight-shooters (pun intended) when it comes to specs, performance claims, and customer support. They don't pad dB numbers, they don't use inflated marketing language, and their warranty matches that same attitude. If something goes wrong with your Polonium under normal use with approved parts, OCL will make it right. That kind of confidence in their own product says a lot about how the can is built.

Do I need to clean it? How do I clean it?

The Polonium is a sealed, welded stainless steel suppressor. It's not user-serviceable and cannot be disassembled for cleaning. The good news is that H900 heat-treated 17-4 stainless steel doesn't corrode and sheds carbon far more easily, so it requires significantly less maintenance attention than rimfire or pistol suppressors. For routine care, some owners will occasionally soak the can in an appropriate solvent to help loosen carbon, then allow it to drain and dry thoroughly before storage. Compressed air or a can of duster can help blast out loosened debris. Avoid submerging the suppressor in ultrasonic cleaners or harsh chemical baths not approved for stainless steel, and never store it with moisture trapped inside. In reality, no cleaning is ever really necessary. The Polonium is low-maintenance by design. Run it hard, wipe down the exterior, and it'll take care of itself.

Can I use the Polonium on 22LR?

No, and this is an important one. The Polonium is a centerfire rifle suppressor. It is not rated or recommended for use with 22LR or any rimfire ammunition. Beyond the caliber mismatch causing poor performance, 22LR produces lead fouling that builds up aggressively inside suppressors. Since the Polonium is a sealed, non-serviceable design, there's no way to clean out that fouling once it's in there. Lead buildup in a suppressor baffles can cause serious problems over time. If you're looking for a dedicated rimfire can, Otter Creek Labs makes the Titanium 22 for that purpose, and we carry a full selection of rimfire suppressors purpose-built for 22LR use.