223 subsonic that cycles an AR? I'm skeptical

[Ranger Roberts]

My travels took me by Cabelas today. I figured I'd stop to kill a few minutes, plus I needed H50 powder. As I was walking through the rifle ammo aisle there was a mid-20's aged fellow holding a box of .223 subsonics, telling his buddy that it will "definitely" cycle an AR.

I'm a "believe it when I see it" kind of guy. Have you guys ever seen factory .223 subsonic ammo that will cycle a stock AR?

 

[Bobson]

If subsonic doesn't cycle an AR, does everyone (and the military) just shoot normal ammo through suppressed ARs? Doesn't that defeat the purpose of running a can on it?

 

[Goosey]

If subsonic doesn't cycle an AR, does everyone (and the military) just shoot normal ammo through suppressed ARs?

Generally speaking.

Today, there is no sub-sonic ammunition currently type classified for use in the calibers provided by any DoD Service [...] There are many contributing factors associated with currently fielded sub-sonic cartridges. First, they are not overly accurate due to large standard deviations in velocity from using a full sized cartridge case with a dramatically reduced propellant charge and a very heavy bullet necessary to reduce velocity below 1,100 Feet Per Second (FPS). The inconsistent propellant distribution prohibits uniform ignition, thus significantly altering the burn profile. Second, the reduced propellant charge creates lower pressures which makes consistent and complete case mouth obtuation (chamber sealing) difficult and makes it hard to get a clean burn of the propellant causing rapid fouling of the weapon. Third, no current sub-sonic rifle round will consistently cycle the action on gas operated weapons.

http://www.acq.osd.mil/osbp/sbir/solicitations/sbir20131/socom131.htm

Doesn't that defeat the purpose of running a can on it?

Nope!

 

[Ranger Roberts]

If subsonic doesn't cycle an AR, does everyone (and the military) just shoot normal ammo through suppressed ARs? Doesn't that defeat the purpose of running a can on it?

A lot of AR's that have a suppressor on them are running 300 blk uppers. I have a 300 blk and run my Saker 762 on it, it runs flawlessly and is very quiet. Just for giggles I have mounted my Saker on an AR running 223, it helps but I wouldn't say it was "hearing safe."

In my years in the military (1996-2006) I have never seen them run 223 suppressed.

 

[Bobson]

Ah, I hadn't realized 300 BLK was quite so prevalent already. I know it's popular but didn't know the military is also using it. That makes sense though. Thanks.

 

[eldon519]

Are you sure he was holding a box of .223 and not .300BO or .22LR maybe? I've never even seen any, let alone at Cabelas.

 

[Ranger Roberts]

Are you sure he was holding a box of .223 and not .300BO or .22LR maybe? I've never even seen any, let alone at Cabelas

100% certain it was 223. When they walked away I picked up the box. It was around $60 for the box. I should have taken a picture of it but it didn't start to bother me until I left the store. I will be in the area Friday again, maybe I'll have time to swing in a take a pic.

 

[FL-NC]

To answer the Bobson, I was in a unit that routinely used suppressors on M4 carbines, 5.56 MK12 rifles, 7.62 SCAR heavy, 7.62 SR25/M110, and 300 win mag MK13 bolt rifle. We didn't use any "specialized sub-sonic ammo" for these weapons. The idea of suppressors isn't and never was to "run silent". They made matters easier for teams in gunfights that happened in enclosed spaces, and in the cases of engagement in larger open areas they made it difficult for the enemy to pinpoint a sniper's (or other shooter's) exact position. The noise didn't carry near as far to alert other people, but of course this became a moot point in the event of return fire from the enemy. Besides, when the enemy starts seeing their people dropping with severe leaks, they know what is happening- even if the weapon is "silent"- which it isn't. Also, we didn't suppress our machine guns, and their is no suppressed shotguns, breaching charges, grenades, etc.- so count on some noise at some point.

 

[Ranger Roberts]

Eldon519:

I was just on Cabelas website and found this:
http://www.cabelas.com/product/atom...der%3BSearch-All%2BProducts&Ntt=.223+subsonic

The box is different from what I saw but I think it is the same manufacturer.

 

[444]

Yeah, I have seen subsonic .223 ammo for sale. And I have loaded a bunch of subsonic .223 ammo myself.

But, it won't cycle the action on a normal AR15.

I never attempted to modify the rifle to possibly get it to cycle with subsonic ammo at the expense of making myself unable to fire supersonic ammo either.

At some point someone will post.....if you are going to fire subsonic ammo out of an AR15, why not just use a .22 LR.....or something to that effect.
No, firing a 77 grain SMK at subsonic velocities isn't the same thing as a .22LR.

I am not saying that it possibly has some practical use, but it is fun to play with. I could come up with possible uses for it, but in my case, it was just a fun exercise in reloading and shooting.

 

[AK103K]

To answer the Bobson, I was in a unit that routinely used suppressors on M4 carbines, 5.56 MK12 rifles, 7.62 SCAR heavy, 7.62 SR25/M110, and 300 win mag MK13 bolt rifle. We didn't use any "specialized sub-sonic ammo" for these weapons. The idea of suppressors isn't and never was to "run silent". They made matters easier for teams in gunfights that happened in enclosed spaces, and in the cases of engagement in larger open areas they made it difficult for the enemy to pinpoint a sniper's (or other shooter's) exact position. The noise didn't carry near as far to alert other people, but of course this became a moot point in the event of return fire from the enemy. Besides, when the enemy starts seeing their people dropping with severe leaks, they know what is happening- even if the weapon is "silent"- which it isn't. Also, we didn't suppress our machine guns, and their is no suppressed shotguns, breaching charges, grenades, etc.- so count on some noise at some point.

This sums things up nicely, and a little more realistically.

I have an AAC M4-2000 and use it around the house quite a bit on a couple of AR's and a bolt gun. Ive never used "subsonic" ammo in the guns I use it with, but from what Ive seen reported, subsonic and cycling in a 5.56 AR, are not normally words used in the same sentence.

While ammo in the USGI to 3000fps range is not movie quiet, it is considerably more quiet than a gun that isnt suppressed. I can shoot my AR's from the carport with no hearing protection, and have no loss of hearing or even a ring. I cant shot a .22LR from a rifle from the same position, without some major hearing loss for a couple of days. The suppressor eliminates about 95% of the muzzle blast. You do still hear the sonic crack of the round going downrange, but its sounds like a .22 out in front of you somewhere.

 

[eldon519]

Thanks Ranger Roberts, interesting stuff.

444,
Will a 1-7 twist stabilize a 77gr bullet at subsonic velocity?

What happens if you fire one in a semi-auto? Does it destroy the case (crunch it from short-cycling)?

 

[Ranger Roberts]

Yeah, I have seen subsonic .223 ammo for sale. And I have loaded a bunch of subsonic .223 ammo myself.

My brother and I loaded a bunch about 2 years ago and shot it out of a CZ bolt gun that he has. It was suppressed with an Omega. It was incredibly quiet. We tried the loads out of 5 or 6 different AR's and couldn't get them to cycle.

I think I am going to pick up some of these factory loads just to see if they cycle. I have an SBR (7.5 inch upper and 10 inch upper) I am curious to try it out of, plus a handful of other "regular" AR's. $60 is a hard pill to swallow for $20 rounds though.

 

[.455_Hunter]

The gov't put out BAA's for "full function" sub-sonic 5.56mm nearly 10 years ago. My company's proposal was not accepted, but other teams were. I guess they are still having problems.

 

[AK103K]

$60 is a hard pill to swallow for $20 rounds though.

Ill say! Thats about 300 rounds worth of my "blasting" reloads.

 

[Gordon]

now you got me interested ! I think I will strap on my new barrel mount chronograph and see if 90 grain Sierra match Kings will work out a 1-7 barrel at 1050 FPS and work the Ar action reliably. I'm thinking a fluffy powder to fill the case with the deep seated 90 grain bullet should do it .

 

[farmerboy78]

Trailboss is the powder, I use it to load subsonics in my .308 win...

 

[yugorpk]

You can stuff a 223 case full of trail boss and load it with the heaviest bullet your twist will allow . It will not cycle the action unless you mod the gun for it.

 

[Gordon]

think you are right about moding the gun by enlarging gas vent hole and lightening buffer and or spring. :banghead: From what I have read even custom 100 grain flat base bullets with around 8 grains of trail boss , which are barely under the speed of sound, won't do it with any rteliablity. Glad I did not proceed further on a seemingly dead end project. Some guys have used 135 grain tungsten bullets but they are not stable at subsoncic velocities out of 1-7 and have damaged suppressors so what would be the point. I am not about to build a dedicated AR that would be potentially unsafe for regular ammo. :banghead:

 

[eldon519]

I doubt it is possible to get it to cycle, butnif you were going to, I think going really slow rather than fast in terms of burn rate would be the way to do it. I know some folks have managed to make cast lead reduced loads cycle by using light charges of slower-than normal powder so that they have a low but long pressure curve.

 

[444]

Trailboss is not the powder in .223.

You cant get enough in the case.
You dont want to compress Trailboss. Check the data on the website.
Against their advice I did anyway. You get velocities all over the map varying by hundreds of feet per second.

There is no shortage of reputable published load data for doing this. At least there is for typical bullet weights. I did 77s and 100s.

 

[444]

Ok, I made that last post from the range. I was shooting and other people at the range kept calling a cease fire so they could look at their targets and after the first few times I started playing with my phone. Now that I am at an actual computer:



There was a time, not long ago, when suppressor ownership was not as common as it is today. I credit the internet and on-line gun forums for getting the word out that it is perfectly legal to own a suppressor, and it is not a difficult process. Various people have always owned suppressors, but the average gun owner didn't know anything about them. About the time they started to become popular, I jumped on board.

At the time, there was very little information out there about loading subsonic rifle ammo. So, when I was playing around with this, I was just winging it. I had the time, I had a range close to where I lived, and I owned a chronograph. At the time, I posted extensively about my loads on a forum that I think was (is?) called Silencer Talk or something like that. But this was probably at least 10 years ago.

My initial thoughts were that I wanted a load that was as close to being supersonic as possible, without actually being supersonic. I also figured that if you were limited by velocity that you should maximize your efforts by using heavy bullets. These fly slower, and they also hit harder for a given fixed velocity. I should point out that when and where I was doing this, it was over 100 degrees every day, so I figured that if I came up with a load that was just below supersonic (every round below), then in the winter it would definitely be subsonic.

The heaviest bullet in .223 that I had was the 77 grain SMK, so that was what I mainly concentrated on but later on I came across some 100 grain, .224", BTHP bullets and I bought 1000 of them. After my last post, I just went out in my building and checked and I still have most of them.

I tried Trailboss powder right off the bat. I was working my way up to just below the speed of sound. I got decent groups at 25 yards and they were very quiet. I found that before I got to where I wanted to be in terms of velocity that I ran out of room in the case for additional powder and when I compressed it, I got WILDLY varying velocities. I went home and did some research and read somewhere that you can't compress Trail Boss. I attributed my crazy velocity variation to that and quit messing with it. It did seem to work OK with 55 grain bullets FWIW. I only played around a little bit with the 100 grain bullets. To be honest, I sort of lost interest in the whole thing. I was hot and heavy into it for about a month, proved that I could do it, saw how some of the loads performed and moved on to something else.

I would be highly interested in hearing what you guys come up with in terms of actual loads that you actually test. I very well might get back into playing with this.

I guess that I should point out that Trail Boss may be OK, if you are satisfied with velocities well below supersonic. It worked fine with heavy bullets right up until I was getting close to a max load (where the bullet went supersonic).

 

[OilyPablo]

You will need the most gaseous slow powder in "maximum" load that gives the bullet speed necessary and a larger port. But beyond that the BCG must be super free moving. The bolt while making a good gas seal must move very easily. All areas where the cam pin contact the carrier must be polished and probably lubricated. Use a very light BCG. AIM makes a lightweight BCG that won't break the bank. Use a light buffer. And use a flat wire PCC spring. I am not saying or guaranteeing this will work, but to make it have a chance I think it would be quite similar to getting a DI PCC running.

 

[444]

I did a search and found the thread I posted 11 years ago about trying to load 100 grain bullets subsonic.

http://www.silencertalk.com/forum/viewtopic.php?f=9&t=4632

 

[444]

Ok, I had a few more minutes to waste this afternoon and hunted down the thread I posted using 77 grain SMKs.

It appears I have to take back what I posted earlier: I did in fact find a good load using Trail Boss powder and 77 grain bullets in the .223. I guess after 11 years my memory faded and I confused the 100 grain loads with the 77 grain loads. Sorry about that, I hope my correcting that and posting a link to the thread with the info makes up for it.

Anyway, this is pretty good info if I do say so myself:

http://www.silencertalk.com/forum/viewtopic.php?f=9&t=3088

Please pay attention to what I posted in there: I was just flying by the seat of my pants and I can't vouch for the safety of this data. Use at your own risk.