Quietest Suppressed AR-15 you could put together is...

[TXAZ]

I have a suppressed Barrett (yea I know that's kind of a joke) but would like a good quality (ala Daniel Defense-ish) very quiet AR-15 with a suppressor.

If you're into these rigs, what combination would you recommend of high quality rifle, suppressor and what ammo?

 

[Reload10]

Hard to beat the numbers a tbac dominus is putting out.

 

[RTH1800]

Some quality 18-20" along the lines of a KAC LPR or SPR type rifle. Thread on can, JP Silent Capture System adj. gas block or Noveski Switch Block you can turn fully off and manually function. Heavy weight buffer in SCS. No semi auto that functions that way will be as quiet as a bolt gun. Turn off the gas and it's another story, but it's not a semi then.

 

[RTH1800]

I notice a lot of folks like to go short when suppressing an AR but below 16" gets loud even suppressed.

 

[Austan]

I notice a lot of folks like to go short when suppressing an AR but below 16" gets loud even suppressed.

Is this due to the use of factory ammo? If the ammo is subsonic upon exit, why would the barrel length matter?

 

[RTH1800]

Now it gets more complex. If you set up your AR to function with SS ammo, it will not be usable in a general sense. WAY overgassed.
Barrel length still matters due to powder burn.
I strongly suggest you run your SS ammo through a bolt gun. Or get a designated SS AR for something like 300 BO.
You did not state what Caliber and I assumed you were thinking 5.56.

 

[TXAZ]

Now it gets more complex. If you set up your AR to function with SS ammo, it will not be usable in a general sense. WAY overgassed.
Barrel length still matters due to powder burn.
I strongly suggest you run your SS ammo through a bolt gun. Or get a designated SS AR for something like 300 BO.
You did not state what Caliber and I assumed you were thinking 5.56.

5.56 was the original intent but just heard from another that I should consider the 300 BO.

 

[RTH1800]

Also remember a SS 5.56 is not really much of a killer. It is basically a heavy bullet 22 RF. To shoot heavies SS you will need a very fast twist barrel Lethal for sure but not a sudden or spectacular killer. It keeps getting more complicated.
When it's all said and done you end up back at at subsonic .308 bolt gun, or at least I have. See my thread on Lone Peak Ti, Proof CF .308. here on SH.
I also do not get caught up on ultra expensive SS expanding bullets. A 30 caliber hole seems to kill well with a Lapua SS bullet.

 

[alamo5000]

I have a suppressed Barrett (yea I know that's kind of a joke) but would like a good quality (ala Daniel Defense-ish) very quiet AR-15 with a suppressor.

If you're into these rigs, what combination would you recommend of high quality rifle, suppressor and what ammo?

It's really going to depend on the can, but 99% of the time if you are doing any volume shooting you will need ear pro no matter what even if it is 'hearing safe' (for a single exposure) per the metered numbers.

It depends on a lot of factors but a lot of the cans out there work best in the 18" barrel length. What you need to be concerned with is the port pop. The barrel is still under pressure when both ends get opened up, IE the bullet leaves the muzzle and the bolt opens up. A lot of that is a function of ammo.

I have experimented with different powders to some success to 'fine tune' this but it still will be loud enough to want to wear ears if you are doing any volume of shooting. That said you can tune it down some but you might lose some velocity.

I have a 10.5" and a 16" that both are suppressed, as well as a 9" 300BLK. It all depends on what you are after and at what distance. The crack of the bullet in flight is around 140 DB (for .223) so once you pull that trigger the neighbors will definitely still hear. It will just be less annoying than 160-170 DB booms going off from pure muzzle blasts.

 

[Austan]

I developed a ss load for a 223 Ar with 16" barrel many years ago as pest control and eventually built a 300blk bolt gun instead. I'm currently working on an AR in 300blk with a short barrel to be suppressd full time and run quiet. I'm interested in seeing the replies you get on components and hope to see something new to me.

 

[alamo5000]

Is this due to the use of factory ammo? If the ammo is subsonic upon exit, why would the barrel length matter?

I have a 10.5 and even 77 grain is nowhere near subsonic. And you don't want to be within 100 yards taking fire from a 77 grain out of an SBR.

To your question though it's all about heat and pressure. Imagine the cork on a champagne bottle. The boom happens when hot gas meets cold atmosphere. The amount of PSI trapped in the barrel is also a huge function of that. On a shorter barrel gas is still expanding and powder can still be burning in some cases. When you decork a high pressure tube with ultra hot gas in it, there is a resulting boom. However when you extend that out to say an 18" barrel the PSI is significantly less inside the barrel.

 

[Austan]

Anyone ever run the atomic ammo subs in 5.56?

 

[PlinkIt]

You'll start with 223... It is NOT quiet

You'll build a 300 so you can shoot subs, and it'll be a great improvement

They you'll pay a fortune for .30 cal bullets that will expand at sub sonic speeds

Then you get a short 9mm upper so you can shoot subsonic 147s that are made to work at subsonic speeds and not cost a fortune

 

[RTH1800]

^^^^
This is one path your journey can take unless you bail and go short bolt gun route.

 

[SSSamurai]

The Thunderbeast videos and stats during the Dominus SR and K testing showed that the port/action noise from a 5.56 often becomes the limiting factor in total suppression. I recommend checking those videos out.

 

[themightytimmah]

223 in an AR platform is just not a good mix for suppression. I’ve got a Sandman L on a 16” recce, and even with an adjustable gas port turned down so that it won’t cycle unsuppressed, the port pop and muzzle crack is loud enough to ring your ears.

I like the post above about using 147gr 9mms out of a shorty upper. I have a similar setup and it achieves the desirable “staple gun” noise level at about half the cost of a Blackout.

 

[LANCER]

SPR or MK12 with AEM 5 is stupid quiet, although super gassy.

 

[RTH1800]

The varied responses are due to folks varying expectations and uses. No supersonic caliber is going to be quiet enough for low profile neighborhood pest removal.
A M12 suppressed 5.56 is still a reasonably quite tool.
If you want super quiet go bolt gun.

 

[RTH1800]

It would be nice if you could meet up with someone who has the items you are interested in and try them out. Where are you located?

 

[SBRSarge]

I’d look at a 300blk with subsonic rounds. You can always go supersonic with it, too, if you need more range or oomph.

I have a 16”, 9” and 6” and they are a hoot with my 762-SDN-6 or Omega on the end.

 

[strikeeagle1]

It's already been mentioned several times, commit to a end-use purpose then select the platform.

A few of the various AR receiver styles, 9mm; .300BO; 5.56.

The 9mm round is generally right at the speed of sound out of a common pistol, suppressed its pretty quiet. A Wilson Combat 7" Glock-based and Rock River Arms 4.5" shown, suppressed mostly bolt cycling noise heard.

My short .300 BO using suppressed rounds, all I hear is the bolt cycle!

Even really short 5.56 is going to have supersonic muzzle velocities; the 4.5" has ~ 1900 fps using Black Hills 50 gr. TSX specific for the caliber short barrel. My FN 5.7 pistol 4.5" barrel has a 2250 fps muzzle velocity.
A FDE Primary Weapons System (piston) and KAC shown.

16" HK 5.56 and Rock River Arms 4.5" shown. The 16" has a 3,000+ fps muzzle velocity, hard to suppress, the sound "crack" is softened.

It's hard to beat at suppressed SBR .300 BO, which would be my choice of the three calibers, generally accepted to be effective against 2 & 4-legged varmints.

Folding stocks are the bomb.

 

[db2000]

5.56 was the original intent but just heard from another that I should consider the 300 BO.

I was gonna jokingly say 300 blk but as you’re just considering it...That’s the way to go. I’d rather have it set up how I want it than squabble over 3-5db. Just my opinion. My Seekins had the suppressor inside the hand guard which I like. Keeps it short. Super quiet with an Omega can and can run semi or full with adjustable gas block and 190 Sub-X bullets hand loaded.

 

[W54/XM-388]

If you need quiet, it needs to be a bolt gun.

TBAC did some tests with a sound meter to get legit numbers and the actual bolt carrier slap when firing a suppressed AR, can wind up being louder than the suppressed shot itself, and that's not a good thing.

 

[strikeeagle1]

^^well then it's not an AR platform which was the OP's thread focus.

 

[POI_Shift]

Its hard to get quiet in an AR. You can suppress the muzzle noise but you will still always have port pop.

 

[alamo5000]

Its hard to get quiet in an AR. You can suppress the muzzle noise but you will still always have port pop.

This is true but the term 'quiet' is all relative. Quiet compared to what?

I find it's always useful to help those not familiar with suppressors to get a realistic expectation, particularly out of an AR.

I have seen internet posts all the time talking about how 'loud' an AR is leading one guy to ask, "If it's still so loud why even bother with a suppressor to start with?" and he definitely had a point.

To the new guy/new suppressor shopper... it won't be ninja quiet where nobody will hear you shooting. It however will be substantially less noisy than before. Depending on the setup of the rifle (barrel length etc) you can probably get away with one or two shots without ear protection but even that is pushing it.

That said (speaking from my own experience) I can shoot a lot more while pissing off the neighbors a lot less. The dogs are also substantially less scared. If I go unsuppressed they go bonkers and we have to try and keep them indoors or whatever (just like I would on the 4th of July etc). With a suppressor it's much more tolerable for all involved.

Sound in general diminishes over distance so if someone is standing a fair distance away they obviously will know you are shooting but it generally won't have the startling boom associated with a gunshot. Suppressors will tame the noise quite a lot but 5.56 is inherently loud out of an AR. The suppressor cuts your baseline down by a whole lot.

If you are talking about other calibers and hosts you can have remarkable noise reduction. A supersonic .22 can be fired without ear pro for the most part and subsonics are just silly pellet gun quiet.

Overall I initially started out buying a suppressor precisely because I didn't want to scare the dogs or piss off my neighbors but I still wanted to shoot more. I have successfully accomplished that and more.

 

[POI_Shift]

This is true but the term 'quiet' is all relative. Quiet compared to what?

I find it's always useful to help those not familiar with suppressors to get a realistic expectation, particularly out of an AR.

I have seen internet posts all the time talking about how 'loud' an AR is leading one guy to ask, "If it's still so loud why even bother with a suppressor to start with?" and he definitely had a point.

To the new guy/new suppressor shopper... it won't be ninja quiet where nobody will hear you shooting. It however will be substantially less noisy than before. Depending on the setup of the rifle (barrel length etc) you can probably get away with one or two shots without ear protection but even that is pushing it.

That said (speaking from my own experience) I can shoot a lot more while pissing off the neighbors a lot less. The dogs are also substantially less scared. If I go unsuppressed they go bonkers and we have to try and keep them indoors or whatever (just like I would on the 4th of July etc). With a suppressor it's much more tolerable for all involved.

Sound in general diminishes over distance so if someone is standing a fair distance away they obviously will know you are shooting but it generally won't have the startling boom associated with a gunshot. Suppressors will tame the noise quite a lot but 5.56 is inherently loud out of an AR. The suppressor cuts your baseline down by a whole lot.

If you are talking about other calibers and hosts you can have remarkable noise reduction. A supersonic .22 can be fired without ear pro for the most part and subsonics are just silly pellet gun quiet.

Overall I initially started out buying a suppressor precisely because I didn't want to scare the dogs or piss off my neighbors but I still wanted to shoot more. I have successfully accomplished that and more.

pulling the charging handle to the rear and just releasing it into battery on a standard ar pattern rifle is roughly as loud as a suppressed 22 bolt gun (114-115dB). Suppressed gas guns measured by the mil std at the muzzle are in the 135-145 range on a 14.5 - 16" barrel. Port pop puts it high 140s/150's at the ear.

 

[alamo5000]

pulling the charging handle to the rear and just releasing it into battery on a standard ar pattern rifle is roughly as loud as a suppressed 22 bolt gun (114-115dB). Suppressed gas guns measured by the mil std at the muzzle are in the 135-145 range on a 14.5 - 16" barrel. Port pop puts it high 140s/150's at the ear.

Nothing much to argue about there.

That said a lot of suppressor manufacturers are now balancing gas flow with gas guns in mind so with some new models you see a little bit louder at the muzzle but you also see a decrease at the ear. Also with some SBR lengths you can see the muzzle and ear numbers shift around a bit.

Overall with 5.56 AR15 hosts people need to wear ear protection no matter what. That said with an overall sound reduction from 165 to 170+ Db down to the low to mid 140 range is quite a lot.

It definitely takes the edge off of the really loud boom coming out of a short barrel. If I shoot unsuppressed I have seen my dogs trembling because of the noise. With the can on though they are not bothered nearly as much. It's also much more neighborly as well.

One thing I haven't studied out but am interested in is how sound travels over long distances. My closest neighbors are a couple hundred yards away so I'm kind of curious about the sound perception from greater distances away.

Like what is it at 100 yards, or 200, or 500 etc. By that I mean to the back or side not just down range.

 

[Weapon_50BMG]

I have several, but the quietest is my 16” 300 blackout with a Wilson Combat Whisper suppressor. It’s one of my favorite to shoot as well.

 

[7WSMShooter]

If you want movie quiet, 22LR bolt action
Then a bolt 300BO.
AR suppressed, 300 BO shooting subs
AR 556 suppressed is more for hearing protection and noise reduction. You’ve gotta adjust your expectations. All the ARs will have the port noise, no getting over it. I just got through building my last AR with a reflex style OTB Can with a break and SLP adjustable gas block and JP captured recoil buffer. I need to work on adjusting the gas system a little more, but it’s very quiet for a supersonic 556. Not playing with subsonic loads on this one. Can goes over barrel almost back to the gas block.
Barrel has just a little bit of machine time on it, with LRI finishing it off with
The x-pattern fluting to drop a bit of weight.

 

[Numb_Skull]

DSR

 

[Twitchy]

If you want movie quiet, 22LR bolt action
Then a bolt 300BO.
AR suppressed, 300 BO shooting subs
AR 556 suppressed is more for hearing protection and noise reduction. You’ve gotta adjust your expectations. All the ARs will have the port noise, no getting over it. I just got through building my last AR with a reflex style OTB Can with a break and SLP adjustable gas block and JP captured recoil buffer. I need to work on adjusting the gas system a little more, but it’s very quiet for a supersonic 556. Not playing with subsonic loads on this one. Can goes over barrel almost back to the gas block.
Barrel has just a little bit of machine time on it, with LRI finishing it off with
The x-pattern fluting to drop a bit of weight.

View attachment 7554910View attachment 7554911View attachment 7554912View attachment 7554913

OK, now I must see some video of this in action. Have you posted any here before?

 

[TxWelder35]

You can eliminate port pop if you hold the sniper button on the side of the upper receiver when firing

 

[7WSMShooter]

I’ll have to get some video of it

 

[Old Man with Gun]

AR platform can do so much that just going for quite can end up with tradeoffs you may not want. You can get a 22lr upper but that has no real energy down range. 300 BO subs are the next level of quiet, but have the trajectory of a rainbow and energy of a pistol. If you want to shoot past 150yds you will really need something supersonic. I have a lot of suppressed ARs and for practical purposes there isn't a huge difference shooting supersonic out of a 9" 300BO, 18" 5.56, 18" 6.5 grendel and a 24" 5.56.

Subsonic in 9mm or 300BO has less noise, range, power and accuracy.

 

[SBRSarge]

And as long as you’re trying to hush the thing, add in a quiet recoil spring like the JP. I don’t know how much difference it makes at any distance from the gun, but it makes the gun seem smoother to me when I shoot it.

 

[Missalot]

It was mentioned earlier, but not discussed: How much quieter will an18" barrel be than a 16" suppressed, assuming .223 supersonic?

 

[Old Man with Gun]

It was mentioned earlier, but not discussed: How much quieter will an18" barrel be than a 16" suppressed, assuming .223 supersonic?

Almost no difference, a person has no chance of telling the difference from 10 feet away.

 

[Old Man with Gun]

It is worth noting that it takes a considerable change in decibels for a person to be able to tell a difference. I find that some suppressors have a more pleasant sound than others, even though they are reported to be about the same decibels. Most important thing is that when it is heard, it dosent sound like a gun shot. Brain registers, something fell over and went thud, etc.

 

[chutinlead]

Something else to consider is the gas length system that usually pairs with each barrel length. IMO a rifle length gas system has a slower smoother recoil impulse which a suppressor only adds to.

I also don't see many 16" AR barrels running a 12" long gas system since that's not a lot of dwell time in the last 4" of the barrel. So 18 would seem to be a sweet spot in ability to run the longest gas system and not overly long to handle.

 

[steve101610]

My favorite so far has been a 10.5” 10 twist 350 legend loaded with maker 280gr subsonic bullets. Very quiet and very effective on game out to 200 yards so far. It is quieter than my buddies 300BO subsonics and actually expands down to 800 FPS.

 

[Old Man with Gun]

I'm not sure if my 300BO subsonics that uses a SWR SpecWar 7.62 or 9mm with SiCo Octane 9 and 165gr is quieter. Both make me giggle.

 

[LeadZeke]

You can knock 5-10db+++ off noise at the shooter's ear if you build an AR15 properly in 5.56/.223. It won't compete with subs in other cartridges, but it will be a hell of a lot quieter to the shooter while offering all the other advantages of 5.56/.223 (or any other supersonic cartridge for that matter).

The absolute quietest you could build would have an impractically long barrel, so I'll pretend you want something useful too. What you want is in relative order:

0. Select the proper suppressor. Lower back pressure is best for an AR15. Higher back pressure will just increase port noise. Pew Science has some good preliminary data here, but to cut it short you basically want the CGS Hyperion/Hyperion K or Helios QD. The build below will help A LOT no matter what suppressor you use, but some suppressors are way better than others off the bat.

1. The longest barrel and gas system you can take for a given build. A 12.5in mid gas is great for a "short" gun while an 18in rifle gas is great for a longer one.

2. If you intend to run 100% suppressed and do not require function unsuppressed, get a smaller "suppressed only" gas port drilled in your barrel. If you need it to run a bit unsuppressed, you can get a hybrid system for the gas port like the BRT EZ Tune. If you need it to run both suppressed and unsuppressed, get a Superlative Arms adjustable gas block and run it in bleed off mode (you might want to do this even with the smaller gas port). All other adjustable gas blocks are inferior when it comes to reducing noise to the shooter.

________________________________Diminishing returns increases rapidly below this line_______________________________

3. Run an LMT Enhanced BCG (or at least the carrier). The delayed unlock from the modified cam pin path further reduces noise to the shooter.

4. Run a heavier buffer and spring (better yet without a buffer retaining pin). Not too heavy on either, a Tubb's flatwire and Vltor A5H2 is pretty perfect in most cases.

5. Get a gas busting CH (like a PRI, Griffin, or Geissele) and run an upper without a forward assist (or get the assist plug).

A setup like this is night and day over just popping an NT4 on an M4A1 clone, or similar. Way quieter to the shooter, and way more pleasant to shoot. I'd recommend a build like this highly.


I'll end with a quick warning about 9mm and .300blk and similar subs in AR15s. Yes they are quieter than supers, but you still get a lot of port noise and the noise of the action cycling. It can be disappointing if you are expecting something really quiet. A 300blk bolt gun is really where it is at if you want quiet + fun with some practicality over and above with a suppressed .22lr gives you.

 

[GUNNER10]

You'll start with 223... It is NOT quiet

You'll build a 300 so you can shoot subs, and it'll be a great improvement

They you'll pay a fortune for .30 cal bullets that will expand at sub sonic speeds

Then you get a short 9mm upper so you can shoot subsonic 147s that are made to work at subsonic speeds and not cost a fortune

This,

Regardless of the can or rifle, its going to be loud, If you get a can that is designed for maximum suppression levels, its going to cause over pressure issues and have excess gas to the face. If you go with a can the was designed with lower back pressure, its going to be naturally louder at the muzzle, quieter at the ear, and have minimal over gassing.

If one is going for quite, they really should consider something like 300BO and run subs. it can be expensive, but it does quite really well

 

[clcustom1911]

You'll start with 223... It is NOT quiet

You'll build a 300 so you can shoot subs, and it'll be a great improvement

They you'll pay a fortune for .30 cal bullets that will expand at sub sonic speeds

Then you get a short 9mm upper so you can shoot subsonic 147s that are made to work at subsonic speeds and not cost a fortune

This is partially why I'm doing a 9mm upper coming up. Wanna see how she do with the heavies. 147 HST's for the win.

 

[Old Man with Gun]

This is partially why I'm doing a 9mm upper coming up. Wanna see how she do with the heavies. 147 HST's for the win.

The 9mm builds are harder to tune quiet, but get there. I have 2, one with a SiCo Omega9k for tiny and one with a SiCo Octane9. Mine are blowback. But since I built mine CMMG and others have created delay blow back uppers closer to HK MP-5 performance. The HK delay roller lockback is the quietest semi 9mm I know of. The 147 HST is very good, but I have to give the win to the 300BO subs with a good can.

I have one 300BO that is tiny, uses a Rugged Razor and is hearing safe, but louder than some of my 5.56 builds even with subs. An adj gas block helps and you need a big can. A 9" can meters around 120db, less than 7" can is over 130db. That is a huge difference.

 

[Old Man with Gun]

 

[Old Man with Gun]

I've moved some suppressors around, but here is some gun porn.

 

[Crews]

Quietest rifle that still accomplishes WHAT?

I’m amazed how many people show up with a pocket full of subsonic ammo and still think they can kill stuff with it.

Nothing wrong with prioritizing being quiet if that’s what blows your skirt up and you’ve got money to burn.

This type of conversation leads to too many people who don’t understand the implications ending up equipment that has terminal performance neutered.

If you are purchasing a weapon to defend your family or put food on the table, a lot of the content in this thread is fun, but irrelevant.

 

[Numb_Skull]

Quietest rifle that still accomplishes WHAT?

I’m amazed how many people show up with a pocket full of subsonic ammo and still think they can kill stuff with it.

Nothing wrong with prioritizing being quiet if that’s what blows your skirt up and you’ve got money to burn.

This type of conversation leads to too many people who don’t understand the implications ending up equipment that has terminal performance neutered.

If you are purchasing a weapon to defend your family or put food on the table, a lot of the content in this thread is fun, but irrelevant.

Get naked, run around a field and let me shoot 300 subs at you then.