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5.56 vs .30 cal Suppressor for 5.56

rybe390

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Minuteman
Dec 13, 2017
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.223 vs .30 Cal for 5.56

I'm having a very hard time deciding if I want to go with a caliber specific 5.56 or 6mm can for a 16" host, or if I'd like to go with a .30 cal can for more future proof/and or multi host use. I already have a sdn6 and a kgm r30 in jail, but I'm having a hard time committing to a 5.56 suppressor when lightweight and short .30cal cans exist and can be used on other hosts.

I'm aware 5.56 suppressors offer the same performance in a smaller package. I am aware that 5.56 specific suppressors are better at the muzzle and better for flash reduction. But the question is by how much? Is it actually noticeable to the end user? Can you get acceptable 5.56 suppression from a .30 cal suppressor?

Do those of you with dedicated 5.56 cans ever wish you had gone a more general can, or are you happy with your decision?

Those of you running .30 cal cans for 5.56, how have you found the performance? Do you wish you had a 5.56 can?

Thanks for the input everyone. I'm weighing the performance benefit of caliber specific with the utility benefit or lack thereof.
 
Lots of people talk about flow through designs, back pressure, over gassing, gas in face, and a myriad of other issues when suppressing an ar15. My feeling is that using a 30cal suppressor on a 223 cal rifle mitigates many of the negative aspects of suppressor use. The only real downside is that a 30cal suppressor is typically dimensionally larger and heavier than a dedicated 223 suppressor. I do not have a 223 specific can but have no issues with a 30 cal can. And, my guns run suppressed or not on the same gas setting.
 
^^a lot of truth^^
I also have a sdn6, recently got it reworked to HUB thread. Ended up buying a Thunder Beast Ultra 7 gren 2, .308 for the lighter weight.
I don’t hear that much difference between .223 and .308 suppressors on a .223. A lot more versatility. No regerts.
One thing very few people mention is tone. Try to shoot, and listen to shots, of the suppressors you are considering purchasing. The meter isn’t everything. Some silencers just have a more pleasing tone when fired in certain configurations. When you hear it, you will know what I am talking about. One example is an old Thunder Beast 30P1 on a .300 Win Mag long barrel. It has a ”thonk“ sound like a mortar firing in the movies. Coolest shit ever.
 
I have a very well used Omega-300 that gets swapped around on all my gassers. Probably 20k rounds through it since it was re-cored. For all the talk about how “overgassed” it should be, it’s no worse than any other flow-through design I’ve shot. Certainly quieter though.

Size is right, it’s a little heavy especially with all the carbon in it, but it’s easily one of the most used suppressors I own because it can do a little bit of everything.
 
I think a lot of it will come down to your use case and budget OP.
 
Good 5.56 silencers such as the cgs sci six, surefire rc2, huxwrx flow556k will absolutely sound better than 7.62 silencers.

https://pewscience.com/rankings
https://pewscience.com/sound-signature-reviews

I'd recommend looking at pewscience and reading reviews.

This graph is in order of back pressure.

5.56_MK18_suppression_plot_6.101_wm.png
 
I use a SiCo Omega on 223’s and 308’s both. I used to swap the ends out on 22 an 30 cal but anymore I just leave the 30cal end on an shoot it. You cood probly tell a diff with a decible meter but I am happy with it
 
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I have a very well used Omega-300 that gets swapped around on all my gassers. Probably 20k rounds through it since it was re-cored. For all the talk about how “overgassed” it should be, it’s no worse than any other flow-through design I’ve shot. Certainly quieter though.

Size is right, it’s a little heavy especially with all the carbon in it, but it’s easily one of the most used suppressors I own because it can do a little bit of everything.

The Omega is a great all-around suppressor, my wife has one.

I will say that it's much gassier than the Abel Biscuit on my ar-15's though. It does have a 6.5mm cap, which probably doesn't help.
 
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5.56 is really hard to make quiet. My vote is for a 30cal can, you'll still need ear pro on 5.56... the 30 cal can opens more options. I dig the Nomad 30 as it has interchangable muzzle end plates to choke off as much gas as possible.
 
Lots of people talk about flow through designs, back pressure, over gassing, gas in face, and a myriad of other issues when suppressing an ar15. My feeling is that using a 30cal suppressor on a 223 cal rifle mitigates many of the negative aspects of suppressor use. The only real downside is that a 30cal suppressor is typically dimensionally larger and heavier than a dedicated 223 suppressor. I do not have a 223 specific can but have no issues with a 30 cal can. And, my guns run suppressed or not on the same gas setting.
You forgot to mention that a .30 caliber can on a 5.56 is also noticeably louder at the muzzle than a dedicated 5.56 can with a 5.56 diameter bore. I used to think it wasn't a huge difference, until comparing my Sandman-S back-to-back with my new OCL Polonium 5.56. To the shooter, you don't really notice it (port pop), but directly beside it, there is a very noticeable difference in DB reduction.

On the same rifle, both using KeyMo setups, gassing seems exactly the same. Backpressure is exactly the same (brass ejects at 3 o'clock with both cans), etc... There is no discernible performance difference with a .30 caliber Sandman-S, compared to my Polonium 5.56...Other than sound reduction...But it's a noticeable volume reduction as a bystander.
 
There is A LOT of 30 cal suppressors missing here to be making such a broad statement. How EXACTLY does he measure back pressure?
That's what I'd like to know... My Polonium ejects brass at 3 o'clock on the same rifle that my Sandman-S ejects brass at 3 o'clock. And according to Jay's charts...The Sandman-S should be MUCH less restrictive than the Polonium... It is certainly louder, I can tell you that much.

However, from my personal experience with both of them, they both gas nearly identical when it comes to getting some slight gas in the face, too. Recoil impulse might actually be slightly smoother with the Polonium (more restrictive = more gases trapped = less recoil), and as a bystander, DB volume is definitely quieter with the Polonium. This is just my unscientific research. But folks are going to think whatever they're going to think.
 
5.56 is really hard to make quiet. My vote is for a 30cal can, you'll still need ear pro on 5.56... the 30 cal can opens more options. I dig the Nomad 30 as it has interchangable muzzle end plates to choke off as much gas as possible.
Nomad is a coaxial type can; correct? Definitely hard to compare that to a standard baffle can.

Definitely a good can, and a great option though.
 
Keep in mind that suppressing a 16" 5.56 is a different game than the same cartridge from a 10.5" barrel. The extra barrel length will result in a system that is much more tolerant of sub-optimal choices.

I personally think that a general-purpose .30-cal can is a great starting point. The Dominus, Nomad, and Helios QD would be at the top of my list.
 
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Keep in mind that suppressing a 16" 5.56 is a different game than the same cartridge from a 10.5" barrel. The extra barrel length will result in a system that is much more tolerant of sub-optimal choices.

I personally think that a general-purpose .30-cal can is a great starting point. The Dominus, Nomad, and Helios QD would be at the top of my list.
Understood and appreciate the input.

I already have a sdn6 converted to hub, and a kgm r30 in jail. Currently looking for cans for the gas guns, which has led me down exploring 5.56 cans, for a 16" and 13.9".

It seems there's two groups. .30 cal does it all and you can't tell, and use the right tool for the job. I'm already a fan of suppressed anything and think my sdn6 sounds good on 5.56, doubly so on 6.5 creedmoor.

My only hangup is being stuck with a 5.56 can, but I'm looking and listening to how they sound vs 7.62 cans and it is certainly different, which is leading me to looking hard at caliber specific because I already have two .30 cal cans.
 
Good 5.56 silencers such as the cgs sci six, surefire rc2, huxwrx flow556k will absolutely sound better than 7.62 silencers.

https://pewscience.com/rankings
https://pewscience.com/sound-signature-reviews

I'd recommend looking at pewscience and reading reviews.

This graph is in order of back pressure.

5.56_MK18_suppression_plot_6.101_wm.png
this graph is in order of absolute suppression rating at the ear and muzzle. The data is very subjective because it doesn't translate to hearing safe levels which typically not many 5.56 cans are at the ear from port pop.
 
There is A LOT of 30 cal suppressors missing here to be making such a broad statement. How EXACTLY does he measure back pressure?
I think he is looking at gas coming though the bolt and or bolt velocity but I haven't paid close enough attention to it.
 
I have several, 5 different calibers.
If I were buying my first can the 30 cal would be my first choice.

But if I had multiple cans, I would add a caliber specific 5.56.

I purchased my 5.56 first and that was a mistake.

In my opinion caliber specific suppressors preform better.

Not getting into the fanboy brand pissy contest because I don't gaf.
 
My only hangup is being stuck with a 5.56 can
It depends on how you view 5.56. For me it's a definite long term staple cartridge, sort of like 9mm. Five years from now, or 25 years from now, odds are extremely good that I will still be shooting both.

If you were only able to get 'one can' (yeah right ;)) then a 30 cal is the way to go. They definitely work but in doing so there are other compromises. Depending on a lot of specifics, a 30 cal can (in general) will be noticeably louder on 5.56 vs a dedicated caliber. The caveat to that is that it depends on which 5.56 can you are comparing to which 30 cal can. There is no generic answer.

Another thing to think about is all of the different mounting solutions you will need. By having cans from different manufacturers, at least potentially, you could become an expert in swapping out muzzle devices if you want interchangeability with multiple cans on multiple hosts.
 
In my experience, muzzle velocity, weight, length, back pressure are generally similar between a 30 cal. and 22 cal. suppressor.

Muzzle flash and sound suppression are also, generally very similar, to the shooter. However, to anyone near the shooter, muzzle flash and actual sound suppression are noticeable different between the two caliber suppressors, sometimes significantly. If the suppressor is meant for reducing my overall signature, I prefer a dedicated, caliber specific option.
 
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If you really are a fan of suppressed anything you will end up buying a lot of suppressors. And you will start dedicating cans to guns. So if you buy a 5.56 can, even if it just lives on one AR that you keep loaded up next to the door, it won't be a loss.

You can read all the charts and graphs you want, but at some point you have to buy and evaluate for yourself. Inform your own opinion instead of letting someone else on the internet do it for you.
I appreciate the response here.

After enough people saying there's a performance difference you can actually hear, and the desire to suppress all of the thing...I ended up buying an ecco machine five by five this week.

I figured with a sdn6 and a kgm r30 in jail, it's time to get something specific for a rifle.
 
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I appreciate the response here.

After enough people saying there's a performance difference you can actually hear, and the desire to suppress all of the thing...I ended up buying an ecco machine five by five this week.

I figured with a sdn6 and a kgm r30 in jail, it's time to get something specific for a rifle.
I've had a Five by Five in jail since august. I'm excited to get it
 
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I appreciate the response here.

After enough people saying there's a performance difference you can actually hear, and the desire to suppress all of the thing...I ended up buying an ecco machine five by five this week.

I figured with a sdn6 and a kgm r30 in jail, it's time to get something specific for a rifle.
You will be pumped. Sweet can. Don't own one, but my next 5.56 build will be very similar. Nick does excellent work, and I know he spent extra time making that gem. I'm sure you've watched his videos.
 
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That's what I'd like to know... My Polonium ejects brass at 3 o'clock on the same rifle that my Sandman-S ejects brass at 3 o'clock. And according to Jay's charts...The Sandman-S should be MUCH less restrictive than the Polonium... It is certainly louder, I can tell you that much.

However, from my personal experience with both of them, they both gas nearly identical when it comes to getting some slight gas in the face, too. Recoil impulse might actually be slightly smoother with the Polonium (more restrictive = more gases trapped = less recoil), and as a bystander, DB volume is definitely quieter with the Polonium. This is just my unscientific research. But folks are going to think whatever they're going to think.

I don't see how you reach this conclusion. The polonium is the gassiest can I've ever used. 10.5 with an A5H3 and 14.5 A5H2 with adjustable gas. Shooting in any kind of rapid succession was brutal. Slow fire, shooting groups, etc isn't that big of a deal but the gas stack on shooting quickly is very noticeable.
 
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If you really are a fan of suppressed anything you will end up buying a lot of suppressors. And you will start dedicating cans to guns. So if you buy a 5.56 can, even if it just lives on one AR that you keep loaded up next to the door, it won't be a loss.

You can read all the charts and graphs you want, but at some point you have to buy and evaluate for yourself. Inform your own opinion instead of letting someone else on the internet do it for you.
Exactly right on all counts! That’s what I started doing, and then putting it on YouTube, just because it gave me something else to learn how to do (video editing). I’m at the point where I’m dedicating cans to guns now, I’m currently up to 9 cans, and counting… 4 Dead Airs, 4 Otter Creeks, and 1 Rugged Obsidian 45. And the collection keeps growing. 😏👍🏼

Starting to feel like a stamp collector…Literally. 😂
 
Since we are making broad statements. A LOT of them don't and also come in different sizes. Don't expect them to sound similar because one guy has tested a handful.

We have data on 308 as well.

back_pressure_suppression_plot_6.81_wm.png

omega_labeled_6.81_wm.png


Btw he's tested 50+ cans on 5.56 already. He hasn't written all the information up yet but he knows the data and had talked about it on his podcast. He's talked about using overbore(7.62 bores on 5.56)to achieve high gas flow being a poor way to achieve good performance on 5.56.
 
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Has anyone on here had a chance to use the velos lbp? Thoughts?
 
Since we are making broad statements. A LOT of them don't and also come in different sizes. Don't expect them to sound similar because one guy has tested a handful.
This is true. My Hydrogen-S (7” / 9 baffles) & Hydrogen-L (9” / 13 baffles) are 100% identical…Except for length and baffle counts. And they even sound different on the exact same gun with the same handloads from the same box. It can’t get much more equal of a comparison than that.
 
Also, after reading this it seems that he made up an equation to theoretically estimate backpressure. There is no measurement of the actual backpressure produced.
Correct, he's using sound. Length of the waveform, rise time, blow down, etc.

The only way to actually get a measurement would be to have a sensor in the barrel.

He began exploring bolt speed but quickly found there are too many variables for it to be reliable. But sound is consistent.

He also mentions that back pressure ≠ blow back but has mentioned on the podcast that in many cases these can correlate depending on design.
 
I don't see how you reach this conclusion. The polonium is the gassiest can I've ever used. 10.5 with an A5H3 and 14.5 A5H2 with adjustable gas. Shooting in any kind of rapid succession was brutal. Slow fire, shooting groups, etc isn't that big of a deal but the gas stack on shooting quickly is very noticeable.
I don’t know what to tell you, but I know mine is not that much harsher than my Sandman-S cans on the same rifles. Full-auto a Sandman-S will still get pretty gassy in stagnant air environs, from my experiences. Occasionally, the range guys will let me function check something by letting me put one of my uppers on one of their M16 lowers just to evaluate a modification or suppressor, but I haven’t done it with the Polonium yet. I know rapid-fire semi-auto it was about the same. 🤷🏼
 
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OpsInc 12th model
338 ultra
I actually shot my 338 ultra gen 1 next to my Magnus both on 223 bolt guns. While close I thought the Magnus was quieter so I asked 2 of my kids to sit out on the porch about 15yds away and slightly behind from my shooting position around the corner of the house so the sonic crack wouldn't be as noticeable. I shot both rifles 3 shots back to back and both kids thought the Magnus was noticeably quieter. Not scientific but definitely interesting and impressive for the Magnus.

20230211_153108.jpg
 
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I have a Sig762QD can and use it on a 300BO and all my ARs And a bolt gun in 223. I tired a 5.56 can and couldn’t tell the difference in sound. SIG556 v SIG762 and I went with the 762 because I’d only need one can.
 
I actually shot my 338 ultra gen 1 next to my Magnus both on 223 bolt guns. While close I thought the Magnus was quieter so I asked 2 of my kids to sit out on the porch about 15yds away and slightly behind from my shooting position around the corner of the house so the sonic crack wouldn't be as noticeable. I shot both rifles 3 shots back to back and both kids thought the Magnus was noticeably quieter. Not scientific but definitely interesting and impressive for the Magnus.

View attachment 8073064
That's because the .308 bore suppresser has less gas escaping with the smaller .223 bullet, compared to the .338 bore suppressor. This is a non-scientific example of why pistol and the multi-caliber cans are less effective than a .30 caliber or caliber-dedicated suppressor on the same rifle.
 
That's because the .308 bore suppresser has less gas escaping with the smaller .223 bullet, compared to the .338 bore suppressor. This is a non-scientific example of why pistol and the multi-caliber cans are less effective than a .30 caliber or caliber-dedicated suppressor on the same rifle.
That's not always true. Design has a lot to do with it not just bore diameter.. It was surprising because the 338 ultra gen 2 tested quieter than the Magnus with a 223 bolt gun. I was thinking the Gen 1 would be on par or not noticeably louder than the Magnus.
 
That's not always true. Design has a lot to do with it not just bore diameter.. It was surprising because the 338 ultra gen 2 tested quieter than the Magnus with a 223 bolt gun. I was thinking the Gen 1 would be on par or not noticeably louder than the Magnus.
Correct, but you were comparing 2 very similar cans, and the .30 caliber was quieter… Therefore… Bore diameter of the can played a bigger role, than simply volume, or baffle count and design.
 
338 Ultra Gen2 is about 3 dB quieter than the Gen1 on 338, while the 338 Ultra Gen2 is about 2-3 dB quieter than the Magnus on most .30 cal or smaller calibers. Some cartridge combinations make them +/- a little different.
 
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New video is up with my new Otter Creek Labs Polonium 5.56 suppressor! This is the quietest 5.56 suppressor I've ever shot, and it sounds amazing!

As always, weapon & suppressor specs, and my personal opinions are in the description box of the video.