Quietest SUPERSONIC AR-15 caliber to suppress?

Greyhunter

Greyhunter

New member
I mainly only have experience with suppressing a 16" mid-length .223 AR-15 so far and it's still a bit loud, but I have very sensitive hearing from previous abuse. I do have an adj gas block which did help reduce port popt. I am planning on building a 20" .223 AR upper to suppress as my research says it should have approx 24% less muzzle pressure than a 16" (= less muzzle blast) and the rifle length gas should have a little less port pop, and of course it will be 4" farther from my ears.
I know there are a lot of guys here shooting .223 as well as wildcat cartridges. Before I buy a .223 barrel, I'm curious if anyone has found a cartridge that suppresses noticeably better than .223 (in a comparable barrel length). It would be nice to stick with .223 but I do reload if there was a significantly quieter cartridge out there.
I have a SilencerCo Omega and Hybrid with .223 endcaps for both.
Thanks
 
Since you're wanting to stay supersonic, keep the 5.56/223. If going to reload and already have 2 large cal cans, go 300 whisper or 458 socom. Both can go super or sub.
 
Use is for an upper to dedicate to thermal night hunting, so that's why I want to stay supersonic. It's tough to judge distance at night, especially with a 2D thermal screen. Primarily coyote hunting but also some raccoons, distances would vary from 50-200+. No pigs around here. .223 is the easy answer because I already have a ton of components for it, but suppressors interest me and quiet guns are just cool. It would be fun to compare calibers like .17Rem or .17Hornet side by side with .223. I've also heard 300blk supersonic and 6.5 Grendel are a little quieter than .223, I'm assuming the larger bores drop pressures quicker?
 
In my opinion the quietest supersonic AR platform would have to be the 300 Blackout simply because it has the least amount of powder
 
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Have a Dead Air Sandman L on an 18" Daniel Defense 6.8 SPC and it is much quieter than my suppressed 16 " .223 AR 15's. Don't wear hearing protection at all when shooting from a stand or on the ground. Wearing ear protection keeps me from hearing the coyotes howling or the rattlesnakes at my feet at night. Use the 6.8 SPC almost entirely except for a Sandman S on a Rock River LAR 47 7.62 x 39 which is now my #2 calling\walking rifle as it is almost as quiet as the 6.8 SPC . Maybe the quality of the suppressors is the deciding factor.
 
Originally Posted By: Dry Creek Have a Dead Air Sandman L on an 18" Daniel Defense 6.8 SPC and it is much quieter than my suppressed 16 " .223 AR 15's. Don't wear hearing protection at all when shooting from a stand or on the ground. Wearing ear protection keeps me from hearing the coyotes howling or the rattlesnakes at my feet at night. Use the 6.8 SPC almost entirely except for a Sandman S on a Rock River LAR 47 7.62 x 39 which is now my #2 calling\walking rifle as it is almost as quiet as the 6.8 SPC . Maybe the quality of the suppressors is the deciding factor.

That is good info. When you say the 18" 6.8 is much quieter than the 16" .223, you are comparing both guns with the Sandman L correct?
I had a ARP 6.8 upper but sold it years before I owned a silencer.
 
Originally Posted By: Kevinfarmer3456In my opinion the quietest supersonic AR platform would have to be the 300 Blackout simply because it has the least amount of powder
-
300B0 suppressor with AR15 platform . high Vel. a 'pistol position' gas block on 300BO it will never be sweet to the ears .
Only if you dedicate it to 'high Vel.only' / no Sub's . move mid or rifle gas position and tune with adj. gas block it will get better.
got to say..suppressed 30-221 rem/300BO in a Boltaction is really a 'sweet snap' out in the open fields on a quiet night .

But for AR's in 223/6mm/25 all suppressed and using adj. gas block .
I have not noticed all that much of a difference for the POP . they are all good to the ear, but never as nice a mellow snap as a boltaction in same Cal.and suppressed .
.
 
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Originally Posted By: IndexFingerOriginally Posted By: Kevinfarmer3456In my opinion the quietest supersonic AR platform would have to be the 300 Blackout simply because it has the least amount of powder
-
300B0 suppressor with AR15 platform . high Vel. a 'pistol position' gas block on 300BO it will never be sweet to the ears .
Only if you dedicate it to 'high Vel.only' / no Sub's . move mid or rifle gas position and tune with adj. gas block it will get better.
got to say..suppressed 30-221 rem/300BO in a Boltaction is really a 'sweet snap' out in the open fields on a quiet night .

But for AR's in 223/6mm/25 all suppressed and using adj. gas block .
I have not noticed all that much of a difference for the POP . they are all good to the ear, but never as nice a mellow snap as a boltaction in same Cal.and suppressed .
.

This follows what I have read elsewhere, that 300BO can be pretty rowdy at the port with supers which I assume comes from the pistol gas system. I know the short 300's are pistol gas and have seen 16" 300 barrels that are carbine gas but I have not seen them in mid or rifle length.
I ordered a 20" .223 barrel for the new thermal upper but I am considering doing something different with my current 16" upper. Maybe a 16" 300 with supers for day time calling and a short 300 upper for playing with subs when my SBR stamp comes.

I went with 20" for the .223 because it was the longest I was willing to hang a suppressor off of, with the hope of it producing producing lower muzzle blast than an 18".
 
Originally Posted By: GreyhunterOriginally Posted By: IndexFingerOriginally Posted By: Kevinfarmer3456In my opinion the quietest supersonic AR platform would have to be the 300 Blackout simply because it has the least amount of powder
-
300B0 suppressor with AR15 platform . high Vel. a 'pistol position' gas block on 300BO it will never be sweet to the ears .
Only if you dedicate it to 'high Vel.only' / no Sub's . move mid or rifle gas position and tune with adj. gas block it will get better.
got to say..suppressed 30-221 rem/300BO in a Boltaction is really a 'sweet snap' out in the open fields on a quiet night .

But for AR's in 223/6mm/25 all suppressed and using adj. gas block .
I have not noticed all that much of a difference for the POP . they are all good to the ear, but never as nice a mellow snap as a boltaction in same Cal.and suppressed .
.

This follows what I have read elsewhere, that 300BO can be pretty rowdy at the port with supers which I assume comes from the pistol gas system. I know the short 300's are pistol gas and have seen 16" 300 barrels that are carbine gas but I have not seen them in mid or rifle length.
I ordered a 20" .223 barrel for the new thermal upper but I am considering doing something different with my current 16" upper. Maybe a 16" 300 with supers for day time calling and a short 300 upper for playing with subs when my SBR stamp comes.

I went with 20" for the .223 because it was the longest I was willing to hang a suppressor off of, with the hope of it producing producing lower muzzle blast than an 18".


-
For strictly sticking with a .223 parent case and it's AR size Bolt . for Shorter length barrel and hanging a suppressor off for easy handling out hunting, But still keeping the speed, and wanting bigger Diam. bullet than a .224 . That was what I went threw running the gambit of Bore size over the years.

224/ 6mm / .30 Bore Size . . For 16" and hanging a Suppressor off . Last year I found that a 25x45 turned out to be big unexpected surprise, .25 Diam Bore was the most efficient for 16" an Running High Vel. . and it a real hard hitter out to 300 yard with 87 grainers .

I love 6x45 . for a great accuracy and flat shooter, it super easy neck-up and shoot . but you need to keep the barrel long to get that speed . and I shot .30-221 rem. way over 20+ years bolt and AR . it is real efficient on the Burn in 16" with suppressor but you wont squeeze more than 2400 fps. with a 16".
.
 
i wouldnt want a 300blk with a mid or rifle length gas system on it. it would likely be so finnicky that it just wouldnt be practical.


carbine gas is very tolerable and easy to work with - my 16" is a carbine gas a runs a h2 buffer with subsonics. its a real treat to shoot that thing suppressed and super. the giggle factor with subs is pretty solid though
smile.gif



my 9" pistol upper has the short pistol gas on it, and its still very very tolerable with the port noise supersonic, but again H2 buffer in back side.

if you were tryign to dial in a pistol gas upper for quiet - an ajustable gas block would be the ticket really.
 
Originally Posted By: IndexFingerOriginally Posted By: GreyhunterOriginally Posted By: IndexFingerOriginally Posted By: Kevinfarmer3456In my opinion the quietest supersonic AR platform would have to be the 300 Blackout simply because it has the least amount of powder
-
300B0 suppressor with AR15 platform . high Vel. a 'pistol position' gas block on 300BO it will never be sweet to the ears .
Only if you dedicate it to 'high Vel.only' / no Sub's . move mid or rifle gas position and tune with adj. gas block it will get better.
got to say..suppressed 30-221 rem/300BO in a Boltaction is really a 'sweet snap' out in the open fields on a quiet night .

But for AR's in 223/6mm/25 all suppressed and using adj. gas block .
I have not noticed all that much of a difference for the POP . they are all good to the ear, but never as nice a mellow snap as a boltaction in same Cal.and suppressed .
.

This follows what I have read elsewhere, that 300BO can be pretty rowdy at the port with supers which I assume comes from the pistol gas system. I know the short 300's are pistol gas and have seen 16" 300 barrels that are carbine gas but I have not seen them in mid or rifle length.
I ordered a 20" .223 barrel for the new thermal upper but I am considering doing something different with my current 16" upper. Maybe a 16" 300 with supers for day time calling and a short 300 upper for playing with subs when my SBR stamp comes.

I went with 20" for the .223 because it was the longest I was willing to hang a suppressor off of, with the hope of it producing producing lower muzzle blast than an 18".


-
For strictly sticking with a .223 parent case and it's AR size Bolt . for Shorter length barrel and hanging a suppressor off for easy handling out hunting, But still keeping the speed, and wanting bigger Diam. bullet than a .224 . That was what I went threw running the gambit of Bore size over the years.

224/ 6mm / .30 Bore Size . . For 16" and hanging a Suppressor off . Last year I found that a 25x45 turned out to be big unexpected surprise, .25 Diam Bore was the most efficient for 16" an Running High Vel. . and it a real hard hitter out to 300 yard with 87 grainers .

I love 6x45 . for a great accuracy and flat shooter, it super easy neck-up and shoot . but you need to keep the barrel long to get that speed . and I shot .30-221 rem. way over 20+ years bolt and AR . it is real efficient on the Burn in 16" with suppressor but you wont squeeze more than 2400 fps. with a 16".
.


https://store.srcarms.com/product-p/25x45-87hc.htm
Is that the round you are referring to? Looks interesting.
 
Originally Posted By: Plant.Onei wouldnt want a 300blk with a mid or rifle length gas system on it. it would likely be so finnicky that it just wouldnt be practical.


carbine gas is very tolerable and easy to work with - my 16" is a carbine gas a runs a h2 buffer with subsonics. its a real treat to shoot that thing suppressed and super. the giggle factor with subs is pretty solid though
smile.gif



my 9" pistol upper has the short pistol gas on it, and its still very very tolerable with the port noise supersonic, but again H2 buffer in back side.

if you were tryign to dial in a pistol gas upper for quiet - an ajustable gas block would be the ticket really.

From a quick search I'm hearing the same thing, go with carbine gas on a 16" 300. Doesn't look like hardly anyone sells a mid length, and saw no rifle length gas barrels. Lots of people say an adj gas block isn't needed on a 300BO but I believe it would probably help. I have a JP Silent Captured Spring (heavy version) and it makes the gun sound quieter to the shooter also. They are a nice finishing touch on a suppressed AR.
 
for most 300blk applications - you're right an AGB isnt necessary, but pairing up pistol gas and a 16" barrel, especailly one being shot supersonic suppressed, its not hard to actually end up over-gassed with them. its one of they very few configurations where an AGB really shines with the 300 blk.


in this case, since we're discussing tuning a suppressed gun for optium noise reduction - the AGB would be a valid path to that goal on ANY port/barrel length configuration.
 
Originally Posted By: GreyhunterOriginally Posted By: IndexFingerOriginally Posted By: GreyhunterOriginally Posted By: IndexFingerOriginally Posted By: Kevinfarmer3456In my opinion the quietest supersonic AR platform would have to be the 300 Blackout simply because it has the least amount of powder
-
300B0 suppressor with AR15 platform . high Vel. a 'pistol position' gas block on 300BO it will never be sweet to the ears .
Only if you dedicate it to 'high Vel.only' / no Sub's . move mid or rifle gas position and tune with adj. gas block it will get better.
got to say..suppressed 30-221 rem/300BO in a Boltaction is really a 'sweet snap' out in the open fields on a quiet night .

But for AR's in 223/6mm/25 all suppressed and using adj. gas block .
I have not noticed all that much of a difference for the POP . they are all good to the ear, but never as nice a mellow snap as a boltaction in same Cal.and suppressed .
.

This follows what I have read elsewhere, that 300BO can be pretty rowdy at the port with supers which I assume comes from the pistol gas system. I know the short 300's are pistol gas and have seen 16" 300 barrels that are carbine gas but I have not seen them in mid or rifle length.
I ordered a 20" .223 barrel for the new thermal upper but I am considering doing something different with my current 16" upper. Maybe a 16" 300 with supers for day time calling and a short 300 upper for playing with subs when my SBR stamp comes.

I went with 20" for the .223 because it was the longest I was willing to hang a suppressor off of, with the hope of it producing producing lower muzzle blast than an 18".


-
For strictly sticking with a .223 parent case and it's AR size Bolt . for Shorter length barrel and hanging a suppressor off for easy handling out hunting, But still keeping the speed, and wanting bigger Diam. bullet than a .224 . That was what I went threw running the gambit of Bore size over the years.

224/ 6mm / .30 Bore Size . . For 16" and hanging a Suppressor off . Last year I found that a 25x45 turned out to be big unexpected surprise, .25 Diam Bore was the most efficient for 16" an Running High Vel. . and it a real hard hitter out to 300 yard with 87 grainers .

I love 6x45 . for a great accuracy and flat shooter, it super easy neck-up and shoot . but you need to keep the barrel long to get that speed . and I shot .30-221 rem. way over 20+ years bolt and AR . it is real efficient on the Burn in 16" with suppressor but you wont squeeze more than 2400 fps. with a 16".
.


https://store.srcarms.com/product-p/25x45-87hc.htm
Is that the round you are referring to? Looks interesting.
.
yep.. Sharps took the time and money SAAMI spec.it, and make a retail supply of Brass and small selection of factory load ammo . but it basic just a ( 25x45 ) necked-up .223 to a .257 . . with No Brass Cut/trimming . just load and go . For moving up larger than .224 Bore, the .25 Bore Diam. is just perfect for 16" and still making speed .
Was bad timing for Sharps being brought out about same time as 6.8spc and 300BO . Sharps got walked-on pretty hard by bigger advertisement push, especially the blanket coverage by Silvers and AAC on 300bo was just HUGE push and they covered most shooting forums to counter any/all negative talk .

I really like the 6.8 spc. but strictly sticking with a .223 AR Bolt and 16" barrel the 25x45 is overlooked especially if hanging extra length of Suppressor off the muzzle . I have got 2800+ FPS with 87 grn. bullets, but there is a sweet node running right into 2700 fps Vel. .
.
 
I’ve found that an adjustable gas block that is adjusted appropriately helps quiet down my .308. Not sure what effect it has on other calibers. As noted above the JP captured spring makes it quieter to my (shooter) ear but others can tell no difference 20 yds away.
 
I was shooting a suppressed .17 Hornet with an Optimus Micro and it was quiet. Unfortunately, the rimmed cartridge would be tough in an AR15.
 
Originally Posted By: Eric_MayerI was shooting a suppressed .17 Hornet with an Optimus Micro and it was quiet. Unfortunately, the rimmed cartridge would be tough in an AR15.

That 17 Hornet looks like a neat little cartridge, too bad it wont work in an AR. I'm kind of stuck on a AR setup since I'm primarily looking for host rifles for my thermal scope and I want semi-auto. I'd probably buy a 17WSM if someone made one that I wanted (that didn't cost $1000+).

I finally had the opportunity to try out subsonic 300blk this weekend with my Omega and Hybrid. It was not silent, but much quieter than an AR in 223. Much less port noise and sounds hearing safe to me. I plan to build a 300 upper to play with and for short range critter control around the house but I don't think it would be the right tool for night calling at longer ranges.

I built a 20" .223 upper last week thinking it would sound better suppressed than a 16". If it is quieter, I can't tell from the shooter's perspective which was a little dissapointing. Wish I had went 18" to save some length with the can.
 
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