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Suppressors Best can on 11.5" 5.56mm?

HansohnBrothers

Silencer Dealer
Commercial Supporter
Full Member
Minuteman
We tested several silencers on our stock Colt M16. Enjoy!

In an earlier thread 'Hide member Fig asked "all things being equal, is there less back pressure out of a .338 can on a 5.56 as opposed to a 5.56 can on a 5.56?" Starting at 2:16 in the video, we tested a .338 and 5.56mm silencers back to back to hopefully answer his question. Rex Silentium was generous enough to make 2 silencers the same size with only the bore size being different.

 
I just watched these videos. Well done. I’m glad to see the Omega is doing well, mine has exceeded expectations.
 
Yup. Omega is tried and true. Loving mine
 
So I’m hoping that you guys put out some more videos. I follow suppressor nation on Instagram which is how I found the videos. Keep up the good work.

And full disclosure, I’m very biased. But it turns out the Q’s Trash Panda has failed to meter better than the Omega on any of the showdowns at the muzzle. It has metered slightly below the Omega at the ear but not nearly the difference their rambunctious owner was claiming.
 
The moral of the story is that there’s no point to a long can, they are all loud at the ear.

Then again I’m one of about 17 people who have an OPS M4S and love it.
 
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The moral of the story is that there’s no point to a long can, they are all loud at the ear.

Then again I’m one of about 17 people who have an OPS M4S and love it.


This is not really the case at all. If you watch their other videos you will see that an adjustable gas block brings most AR configurations down to the 140db range. High back pressure cans are a little louder, while low back pressure cans are a little quieter. Here is an example video (they have a bunch) showing just that:



RMS Hopaii is louder at the ear on a 16in with no AGB than it is on a 10.5in with an AGB. In other words, a good adjustable gas block (and proper buffer) will knock ~4-7db off the at the ear numbers depending on configuration.

Short cans are great and have their place, but don't be confused about the at the ear performance. Bigger cans usually come out quieter once you properly configure the AR.
 
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It all depends on design. That is what all this testing shows. Generally shorter cans will have less back pressure, but suffer at the muzzle. As Todd from DA states, if you are starting to go over 146db at the muzzle, your at the ear numbers are irrelevant because the splash-back from the muzzle will be 140db++. And some shorter designs try to make up for this with higher back pressure stacks for bolt guns.

So basically if you are looking for a can that is as short as possible while still being somewhat decent at not blowing out your ears rather quickly then you want a can that will do <140db at the ear (the lower the better) and <146db at the muzzle in conditions closest to those you will be using it in. Remember that ammo, weather conditions, hosts, etc. can all dramatically change suppressor performance. Also keep in mind using suppressors indoors (which is what most people who want short cans will be using them) means that you want <140db at the muzzle because inside a car/hallway/bedroom there will be a ton of sound reflection. If your goal is not to instantly cause some hearing damage that is.

Having those kind of requirements really narrows down the field of candidate quite a bit, and many of the shorter cans just do not cut it for <140db at the muzzle (some of the best are cans like the Dead Air Nomad might just squeak in). Now you can throw that out and just take whatever sound reduction you can get at the muzzle as it will be leagues better than no suppressor at all and prioritize OAL instead. That is what most folks do who do a lot of serious CQC and you see cans like the Dead Air Sandman K, Surefire Socom II Mini, YHM Turbo K, Brevis II Ultra, and so on specifically made for those customers.
 
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I’ve some experience with dedicated suppressed setups. If your port is sized correctly for your ammunition, a highly adjustable gas block is only useful for adjusting for gas port erosion. A 2-3 position selector is good for switching from suppressed and unsuppressed. Most people use an AGB to adjust for an incorrectly sized port. I always just cut back a barrel without opening the port. In that context a .063” gas port was far too large in a 10.7” Colt barrel. .093” was right on a 17” M16A2 barrel with OPS cans.

If I can’t shoot suppressed and unsuppressed without adjusting the gas block with a tool, that’s a dealbreaker for me.

In any case your last post hit the nail in the head, you’ll have so much deflected sound regardless of the can when shooting indoors that you’ll want to wear your muffs or commo anyway.

The only time I ever felt a suppressed 5.56 was remotely comfortable without ear protection was a full sized can on a 16” barrel, fired in an open field with knee deep snow.
 
I certainly agree that significantly reducing the gas port will yield almost the same results. Obviously you trade simplicity for a narrower window of operation. The one caveat here is that the Superlative Arms bleed-off AGB supposedly further reduces noise to the shooter via a faster reduction in back pressure. Preliminary tests with a non-spec meter showed this was true, but someone with a proper meter needs to verify.

You should certainly always be wearing earpro when shooting, suppressed or not. My point was more for folks here who are thinking about bump in the night/CQB/patrol stuff where they don't have the time/ability to grab their earpro and still need to shoot their AR in a confined space. And that trade really comes down to how much hearing/situational awareness do you want to give up vs. the OAL of the can. Most go for maneuverability in a shorter can, but I can see a small niche for people who have more modern "open concept" homes where suppressor length isn't as much of a concern going for longer quiter cans on home defense guns. Even 3db less wills save some hearing in the extremely unlikely event you needed to use it without earpro indoors.
 
Personally I’ve been of the opinion that the few extra decibels, even given their logarithmic nature, aren’t worth the length. What I mean is that for the length of a 10.5” gun with the long 762 cans that were all the rage I could have my KAC CQB on a 13” barrel.