I am hoping Smudge will take charge here, as he just took possession of his new Polonium. It's a can I am curious about. I have had a good experience with their OCM5 silencer lately, and I was happy to hear my LGS had a Polonium on the way.

I was able to handle it today. One thing jumped out at me: The blast baffle is a uniform concave shape; the opposite of what is typical. I have seen flat blast baffles, perforated blast baffles, convex or conical blast baffles, etc, but never a spherical concave one.

Yeah, I was looking at that last night. I pulled the direct thread adapter that comes with it and compared it with the Griffin Explorr, just looking through the two to see what and how they're different. Your description of tha baffle shape is apt. Internally, these cans are very different, not just baffle shape and design, but the Explorr has a much bigger blast chamber. I also weighed them, and with the direct thread adapter, the Polonium was 14.5oz and the Griffin 8.5oz.

I haven't yet shot any of the cans I picked up over the last few days. I have three cases of M193 arriving some time tomorrow, but the hold up is now a Griffin Plan A XL adapter. I had bought a Griffin Plan A (their taper mount to HUB/1.37x28) for the Polonium, but my searching didn't yield the answer I can now give the internet: a 2.25" muzzle device is too long for the Polonium's blast chamber by about a quarter of an inch. So, I'll have an added .8" of length on it when it's all said and done. Ordered it from Griffin yesterday as I found a $10 off coupon code that worked and dropped the price shipped to cheaper than the only other place that had them in stock - Midway. I was happy to not give Larry Potterfield the money anyway, but Griffin hasn't shipped it yet. Hopefully I have it in hand very soon.

It will be about a half inch longer and at least twice as heavy as the Griffin can when it's all said and done, but I will be able to do a direct A/B comparison with them on an 11" Bren 2 and an 11.5" URGI to start with. When the ATF gets back around to my PS90, I'll throw the EZ Brake on it and be able to A/B them on it as well, purely for the giggles. The P90 design will apparently beat itself to death with high backpressure cans, and the Polonium probably falls into that territory, so it won't see a lot of rounds on that particular gun. I'll eventually put a Griffin muzzle device on my 16" lightweight pencil barrel build and see which can it likes better.

I got to shoot a Polonium on an 11.5" or 10.5" AR on Saturday (it was one of the two), and then immediately picked up a 14.5" with a Polonium K on it. The shorter AR with the full size Polonium was far more pleasant to the ear. Noticeably much quieter. I got to do this comparison both as the shooter, and standing six feet to the shooter's 3:00 and 4:00 for three friends who also shot them. The results were consistent - the full size Polonium is very quiet, both at the ear and within a few paces of it being fired. My friend who has a K in jail was disappointed, and said he wished he'd gone with a full size. I was pleased with my choice.

Oh, after shooting the two, one after the next, I then tried out the OCM5 on a "Gordon" clone. It wasn't a direct A/B, but it wasn't noticeably quieter than the full size Polonium like I thought it would be. They sounded pretty similar to me at the time.

The Reddit NFA circlejerk shouts a chorus of "just get a Polonium K" for all barrel lengths. Andrew, Otter Creek's owner, has said in several places that I've seen that he likes the full size for the shorter barrels and a K for 16-20" barrels, that it seems to end up about the same results in terms of suppression and weight. I'd say that's probably right.

No conclusions as yet, just lots of anticipation. The NFA game involves a lot of waiting, and now I'm waiting on an adapter instead of a stamp, so I guess there's worse things. While it was a lack of planning and an impulse buy that led me into two fairly different 5.56 cans, I'm happy I'll have two right off the bat, and I can sort of pick and choose what works better on individual rifles rather than just tune everything around one can to start with.

I’ll post it here as I’m looking at OCL cans, but how important is mounting device selection? I saw a few videos of the new Surefire can, does brake vs flash hider matter for all suppressors?

I can only speak to what I've read and heard so far, but yes, it matters. A brake is going to be quieter and have less flash than a flash hider will. A brake is going to be easier on your baffles than a flash hider. A brake acts essentially as a sacrificial initial blast chamber, so you get better performance and more longevity out of a can. The downside is that brakes generally offer no flash suppression without the suppressor, and they can often be loud as shit. Trade offs.

I went with the linear comp to get kind of the best of both worlds, or least that's the way this one is billed. It's got an endcap, so it acts like a brake, but it direct the flash forward because of the shape and some added vent holes around the outer perimeter of the front. So, you basically get both at the cost of a longer unit. The "EZ Brake" that came with the Griffin can is very short, but looking at it, it's very likely going to be quite loud without a can mounted, so I'm putting it on the PS90 to get around that.

There was recently a post where I think either Otter Creek or Griffin took a can and showed it after I forget how many rounds with a three prong or four prong flash hider and showed some erosion on the baffles from what is essentially flame cutting because of the flash hider. They said brakes simply don't do that. Whether that's an issue someone would worry about is up to them to determine, though. How much you're going to shoot, how fast and thus how hot you're going to get the can, how often are all considerations. Essentially, these are wear items, which sucks because of the tax stamp and the wait. The good news is, suppressors can be rebuilt by either the manufacturer, or a machine shop like Ecco Machine, provided your serial and caliber markings are mounted where they won't get altered by removing the baffle stack.

Got the longer Griffin taper mount adapter in. Haven't rigged it up yet. I don't have a vise, and this is all new to me, so I haven't done anything but check things hand tight. Seems to all go together fine. I'm not sure exactly what I want to do yet as far as other mounts and systems for other rifle, so I'm hesitant to Hot Lock this adapter in. I'll probably just crank it down as best I can with their included vise block with some clamps on my work bench and go for it.

The Polonium is noticeably longer and heavier, especially with this mount on it. I was wrong before about the Griffin, it's 9.5oz at 6" 1/32nd and with this mount, the Polonium is 16.25oz and 7" on the nose. That's quite a difference and very noticeable when mounted on a rifle. So far, I've only had them on 11.5" rifles, I expect it'll only get more pronounced when mounted on longer barrels.

Still haven't shot them yet. Things have been hectic here. I have a night shoot on the 25th, should be anywhere from ten of us to a couple dozen, so I need to get both function checked, get my zeros confirmed and everything dialed in before then in the hopes I can get some good footage of both under NODs and with any luck, some comparisons against other cans and setups. Should be fun if nothing else, but hopefully educational as well.

To that end, I ran across this video today. Polonium compared with an AB Warthog and Rugged Razor. I think it did really well against both and I'm glad I went with it so far. The Warthog made it to my short list, so this was good confirmation.

The Warthog is an interesting one. I hate to be that guy, but the look of it kind of puts the brakes on, for me. It seems to be a very good performer though.

The size/weight stats you stated for the Polonium are not out-of-line for a "proper" hard-use silencer, as you know.

I think the vise block Otter Creek includes is cool. That approach allows for elimination of the spanner wrench notches, which makes for an aesthetically-pleasing can. Though I kind of wish they softened the front edge of the can, but now I am really splitting hairs on non-performance-oriented stuff.

That Griffin (Explorr .224 utility?) is only that weight without a mount, right?

The AB cans get the "ribbed for her pleasure" comments, but the look doesn't bother me. If you look at a cross section of those cans, it's part of how they cycle the gas around. I get it, though. Even for the most utilitarian guys, if something looks unappealing, you're not gonna want to use it.

Explorr 224 Taper mount total weight, ready to just thread onto the gun. Yeah, I mean, the Polonium's right in there in size and weight with most of the rest of the field. It would be unfair to judge it by the Explorr, but rather the other way around and realize the Explorr is exceptional in terms of weight compared to most of it's competitors.

My M4SDK is evidence-enough for me that Griffin makes a good can. I imagine the Explorr will be as good, and that you'll be pleased. That being said, I'll be surprised if the Polonium doesn't noticeably out-perform it.

The TBAC testing chart shows that "K" cans can be quieter at the ear. I hope you're able to compare on the same host, as the shooter, and as an offset observer.

Yeah, I'm gonna have a friend shoot my rifle while I observe. Since I can mount both cans on it, should be a good opportunity to A/B in a more controlled setting.

One of the guys who is going also just brought a Polonium home. I asked him if he got all his mounts figured out and what he's got it mounted on. Haven't heard back yet. I got to shoot one of his rifles, I think it's a pinned 14.5 or a 16, so it'll be interesting to see how each can performs on the different barrel lengths. I'll try to get some footage of them shooting from off to the side and see what kind of visible signature differences there are as well, like muzzle flash and gas venting, etc. I haven't done anything in regards to tuning yet, I don't know if he has.

One of my other friends who is going to be there and probably the one I hand my rifle to has a Polonium K in jail. He's up over 200 days and I keep trying to get him to start bugging ATF, but he won't do it. If he had, he'd probably be bringing it out to compare with us.

Oh, and as for K cans, I dunno that I would call the Explorr a K can. It's shorter than the Polonium, but it's got the same number of baffles and a much longer blast chamber to it, plus their Eco Flow baffle design, so I'm hoping it won't be as gassy. If it's noticeably louder, I'll be a little disappointed, but I bought it mainly on the weight. There wasn't enough review material out on it to really see what it would be like. The NFA Review Channel guy on YouTube was really impressed with it, but the guys on Reddit say he's a shill, so who knows. I'm primarily looking to figure out which one is gonna go on my night carbine, and you know that means hanging a lot of shit off the front, or Hydras and dive boards and risers oh my. Weight may figure into it more than suppression in this role. We'll see how it shakes out.

I need to get it to the range hopefully some time early this next week to wring everything out, so I may hopefully have some things to relate by midweek.

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That's quite a difference and very noticeable when mounted on a rifle. So far, I've only had them on 11.5" rifles, I expect it'll only get more pronounced when mounted on longer barrels.

Memories of the unsuppressed front end will fade. The silencer is now standard equipment for you. It's worth the weight and length.

Of course shorter/lighter is better, when comparing one silencer to another, but try to forget about what the gun felt like without it at all.

This message has been edited. Last edited by: KSGM,

Oh, I worded that poorly. I meant the difference between the two cans mounted on a rifle, not the weight difference between suppressed or not.

Yeah, I expect that going forward, the only times I’ll not have a can mounted on an SBR is for transport or cleaning. I basically wound up with rifles at 16” barrels, but a little more front heavy and a lot quieter. I’m ok with that tradeoff.