OCL Polonium Full Size and K Observations

[Dutch110]

None of this will be earth shattering. And if you are researching these cans you probably already read this elsewhere. It's mostly real world confirmation

Polo Full Size - Amazing sound suppression, especially for the cost. Back pressure is a bit much on the 11.5 and 10.5. It's gassy. I mean a LOT gassy. However put it on my 14.5 and its not objectionable. Ill be adding some tid bits to see if I can reduce if (charging handle etc) but I could live with it as is

Polo K - Bought this specifically for the 11.5 and 10.5. Shot it for the first time this weekend. I was genuinely surprised at the sound suppression compared to the full size. Is it louder? Yes, but not by a lot. And the gas reduction is night and day compared to the full size on these two rifles.

Both are HUB compatible. I went with the Rearden Atlas and have no complaints at all. Simple and stays put. And doesn't cost an arm and a leg.

Set up

14.5 has a Centurion Barrel A5 RE with a Sprinco Green and A5H2. No issues with our without either can even with cheap steel case

11.5 has a G barrel. Carbine RE with a standard spring and an H3. I tried both a Sprinco Red and Blue in this one but it would not cycle unsuppressed. I may try the G spring in this one or may just go with the same A5 set up I have on the other two. No issues with or without either can.

10.5 has a Colt surplus FSP barrel. A5 RE with a Sprinco Green and A5H2. No issues with our without either can even with cheap steel case

[asolo]

I will second this observation. All I run is deadair sandman k/s/nomad Ti. A guy I frequently attend classes with has the polonium K and I was stunned how quiet it was for its size. No clue about customer support should something go wrong but it certainly seems a good bank for the buck suppressor

[Dutch110]

I will second this observation. All I run is deadair sandman k/s/nomad Ti. A guy I frequently attend classes with has the polonium K and I was stunned how quiet it was for its size. No clue about customer support should something go wrong but it certainly seems a good bank for the buck suppressor

Funny you should mention this as after all the CS issues floating around the interwebs with certain makers recently I reached out to Andrew at OCL and asked him the same question. BTW that dude is hyper active on the NFA Reddit sub and is very involved with his client base. Have had some great discussions with him over there on set up and appropriate can for specific applications. Anyway his warranty is pretty much you break it we fix it. They strive for turn around of 2 weeks or less. He said the only exception is if somebody does something stupid like uses a hand drill to try and open up a 5.56 can to 30 cal. This has apparently happened. In that event they may charge a stupid tax of a few hundred to fix it.

[Dutch110]

BTW I ordered a Polonium 30 cal can to use on one of my 7.62 x 39 SBRs last week. I already have a Razor 7.62 to compare it against so should be interesting.

[Clint]

The general observation of Full Size vs K can are usually true, but there can be exceptions.

The Turbo-K for example, does a good job with suppression and has reasonable back pressure.

A few of the 30 cal K cans are much louder and frankly not very good on 556.

Dedicated bore 556 cans tend to perform better with 556 than their 30 caliber versions.

[Dutch110]

The general observation of Full Size vs K can are usually true, but there can be exceptions.

The Turbo-K for example, does a good job with suppression and has reasonable back pressure.

A few of the 30 cal K cans are much louder and frankly not very good on 556.

Dedicated bore 556 cans tend to perform better with 556 than their 30 caliber versions.

I get why people buy a 30 cal for their first can as a "do it all" can. But realistically how many people end up with just one can? They get that taste of shooting suppressed and want more. But then again, not everyone can afford to stack cans high and deep in the safe. For fun I am going to try out this Polo 30 on a few of my 5.56 rifles alongside its brothers (thank you Rearden.) But it's going to live on an X39 SBR long term. At the risk of being an OCL simp, I think they state it best in their product description of the Polo 30:

https://ottercreeklabs.com/product/polonium/

[Clint]

Good Plan.

What you'll likely find is the Polo-K will perform very closely to the Polo-30 in the areas of sound and back pressure, while being 1" shorter and 2oz lighter.

The effects of the extra baffles and larger bore tends to cancel each other out, so you end up mostly even on 556.

The extra weight and length does allow extra flexibility to run it on 30 caliber guns.

I get why people buy a 30 cal for their first can as a "do it all" can. But realistically how many people end up with just one can? They get that taste of shooting suppressed and want more. But then again, not everyone can afford to stack cans high and deep in the safe. For fun I am going to try out this Polo 30 on a few of my 5.56 rifles alongside its brothers (thank you Rearden.) But it's going to live on an X39 SBR long term. At the risk of being an OCL simp, I think they state it best in their product description of the Polo 30:

[Dutch110]

Good Plan.

What you'll likely find is the Polo-K will perform very closely to the Polo-30 in the areas of sound and back pressure, while being 1" shorter and 2oz lighter.

The effects of the extra baffles and larger bore tends to cancel each other out, so you end up mostly even on 556.

The extra weight and length does allow extra flexibility to run in on 30 caliber guns.

That will be awesome if that is the case. It could then serve as a back up SBR can if I ever need it. But I like this K can so much I will probably buy a second one at some point. The full size Polo is a gassy beotch on those SBRs. That one is living on my 14.5 now.

[Dutch110]

So first off this is highly unscientific, is based on solely my ear, shooting my gun, at an indoor range (2 of these are still in jail) in a lane next to the wall. So caveat emptor or something.

Shot the Polo 5.56, Polo 30 and Polo 5.56 K today back to back. All using Rearden Atlas mounts and RS2s. I used my 11.5 SBR which has a G barrel, standard carbine spring, H3 and using one of the new generation BCM charging handles. I used a grab bag of different brass cased 5.56 ammo from my Bin O' Wayward Rounds. 200 lead nuggets were sent to meet their maker in the great backstop in the sky. Here are my observations:

Sound Suppression ranked from most quiet to loudest

1. Polo 5.56
2. Polo 30
3. Polo K 5.56

Gas ranked from most gassy to least

1. Polo 5.56
2. Polo 30
3. Polo K 5.56

On the sound suppression I had to go back and forth between the Polo 30 and Polo K before I could get a good read on that. I say that meaning it wasn't so dramatically different that it was blatantly obvious immediately. And the tone on the 30 felt a bit deeper too.

At 25 yards shooting free hand all rounds landed inside the 9 ring on a silhouette target. I wasnt shooting for groups but any POI shift was negligible.

I think if I had bought the 30 and had no other experience with the other two I'd be perfectly happy with it as a multi use can. The K is still my favorite on the shorter barrels. The slight increase in noise is worth it, to me, for the reduction in gas and the shorter length.

Really looking forward to putting the Polo 30 on my 11.5 X 39 once I get the barrel swapped. But in a pinch wouldn't hesitate to throw it on one of my 5.56 rifles.

[Clint]

Thanks for the report.

These findings seem consistent with basic expectations.

Smaller Bore = more suppression (quieter) and higher back pressure.
Less baffles = lower suppression (louder) and lower back pressure.

More baffles = more suppression (quieter) and higher back pressure.
Larger bore = lower suppression (louder) and lower back pressure.

A theoretical Polo K30 would almost certainly come in a distant 4th on both lists.


Since the sound suppression is reported "at the ear", it is correlated with back pressure, as over gassing increases ejection port noise.


The most interesting comparison is between the 30 and the K.

Which is better, 5x30 cal baffles or 4x22 cal baffles ?

The 5x30 cal baffles appear to flow slightly better and have slightly lower back pressure, resulting in slightly better at ear performance.

The measured "at muzzle" numbers may be similar between the 30 and the 556K, but are likely to be reversed and favor the smaller bore.


This essentially sums up much of the conventional wisdom around suppressors on gas guns and that is:

"A full size 30 cal suppressor sounds about the same and is a little less gassy than a 556 K-can on the AR platform, at the expense of some added some weight and length, but gives flexibility to use with 30 cal."

So first off this is highly unscientific, is based on solely my ear, shooting my gun, at an indoor range (2 of these are still in jail) in a lane next to the wall. So caveat emptor or something.

Shot the Polo 5.56, Polo 30 and Polo 5.56 K today back to back. All using Rearden Atlas mounts and RS2s. I used my 11.5 SBR which has a G barrel, standard carbine spring, H3 and using one of the new generation BCM charging handles. I used a grab bag of
different brass cased 5.56 ammo from my Bin O' Wayward Rounds. 200 lead nuggets were sent to meet their maker in the great backstop in the sky. Here are my observations:

Sound Suppression ranked from most quiet to loudest

1. Polo 5.56
2. Polo 30
3. Polo K 5.56

Gas ranked from most gassy to least

1. Polo 5.56
2. Polo 30
3. Polo K 5.56

On the sound suppression I had to go back and forth between the Polo 30 and Polo K before I could get a good read on that. I say that meaning it wasn't so dramatically different that it was blatantly obvious immediately. And the tone on the 30 felt a bit deeper too.

At 25 yards shooting free hand all rounds landed inside the 9 ring on a silhouette target. I wasnt shooting for groups but any POI shift was negligible.

I think if I had bought the 30 and had no other experience with the other two I'd be perfectly happy with it as a multi use can. The K is still my favorite on the shorter barrels. The slight increase in noise is worth it, to me, for the reduction in gas and the shorter length.

Really looking forward to putting the Polo 30 on my 11.5 X 39 once I get the barrel swapped. But in a pinch wouldn't hesitate to throw it on one of my 5.56 rifles.