Barrel length and suppressor question

[Bearclaw]

OK I'm looking putting together a AR pistol for now. I may eventually turn it into a SBR but for now it will be a pistol. I was thinking about going with .223. With .223 how much difference does it make if the barrel is 10.5 or 7.5-8 inch? This will be used mostly for 100 yards and under?

Second, a friend said there wasn't much of a point suppressing .223. I would like to do that to this rifle and anther AR that I already have. I know 300 blk is the BEST caliber to suppress and I might move that way when ammo is cheaper for it or I start reloading.

Any input would be helpful. Thanks

 

[Wolverine6G]

I suppressed my 223 and I love it. Most suppressors are rated for 11.5 inch barrels. Best to research suppressors first. 300Blk is BETTER if your shooting subsonic you will not have to recharge the rifle. 223 and subsonic there isnt enough backpressure to cycle the bolt.

Someone else smarter than me would chime in.

 

[Faine]

Be careful when using short barrels and suppressors, on top of extra baffle damage from the gasses and what not you could also void your warranty as many if not most suppressor mfgs have minimum barrel lengths for their suppressors. As I understand it .223/5.56 has increased unreliability the shorter the barrel gets. Also something to take into consideration. Personally I wouldn't take that caliber under 10.5" but that's just me.

 

[Brian Ski]

Not sure if you have a lot of experience with suppressors. Any bullet that travels faster than the speed of sound (approx 1050 fps) will crack going through the air. It will cut the sound down but the crack is still pretty loud.

OTOH... The shorter the barrel the larger the gas port needs to be to cycle the bolt. Problem you get into is that the larger the gas port the higher pressure gas unlocks the bolt, which in turn is harder on the bolt. Push your limits and bolts break.

Not sure about 300 being the best caliber to suppress. It depends what you want to do. If you drop any rifle bullet down to 1000 fps, your range is going to drop off considerably. A .223 is running about 2900-3100. Pretty fast. There have been rumors of a couple guys making subsonic .223 (that would cycle) but the prices were very high and they seemed to disappear. With the 300 they have a heavy bullet going slower. That way they can keep higher foot lbs of energy. I think my .300 win mag is about 3200 fps. Drop it to subsonic 1000 fps. Quite a drop. Also when you are talking about suppressed ammo, it is time to start rolling your own. Cheaper than buying and you can tailor match what you want. Then comes along a chrony to see how your ammo is performing.

A lot a Hollywood myths about what suppressors can do. A suppressor on a rifle does quiet the rifle but it is still loud. If you hear a shot from a suppressed rifle you can hear it, but not tell where it came from. That is why our snipers use suppressors.

Not sure on your knowledge of suppressors, not wanting to talk down, just help fill in some gaps.

 

[ryknoll3]

OK I'm looking putting together a AR pistol for now. I may eventually turn it into a SBR but for now it will be a pistol. I was thinking about going with .223. With .223 how much difference does it make if the barrel is 10.5 or 7.5-8 inch? This will be used mostly for 100 yards and under?

Second, a friend said there wasn't much of a point suppressing .223. I would like to do that to this rifle and anther AR that I already have. I know 300 blk is the BEST caliber to suppress and I might move that way when ammo is cheaper for it or I start reloading.

Any input would be helpful. Thanks

.223 is still going to be loud, but it's much better suppressed than not. As far as barrel length goes, know that a 7.5-8" barrel on a .223 should be considered nothing more than a fun range toy. Velocity is slowed too much for reliable fragmentation, and you are more likely to run into functioning issues, though you may get something that runs just fine. That said, if you want to do it, go for it. The shorter barrel won't really be much if any louder suppressed than the longer barrel, you'll just have lower velocities.

As for a suppressor, you would probably want to look at a .30 cal suppressor. Some of those are rated for shorter .223 barrels than a .223 can would be because of the larger bore. However, the Saker 556 is rated to 7" barrels, so you'd be good to go.

 

[Sling10mm]

I would recommend first deciding if you want to run a suppressor or not, then decide on a caliber, and then decide on the make of the suppressor and use their guidelines for barrel length. If barrel length is more important than running suppressed or whose suppressor you want to use, then I would at least research who warrants their cans for use with the shorter barrel length so you know what your options are later.

For me, I knew I wanted to suppress several platforms, so I chose a 30 cal can to run on two 5.56's, a 6.8, and a 7.62x51. It isn't as efficient with the smaller calibers, but still works well. In this case the 5.56 barrels are 18" and 11.5", and the 6.8 is 11.3". I believe AAC says you can go shorter with smaller calibers through the larger suppressor, but I can't remember the exact lengths.

 

[Brian Ski]

I know 300 blk is the BEST caliber to suppress and I might move that way when ammo is cheaper for it or I start reloading.

Any input would be helpful. Thanks

Hey I know this is not what you asked, but not sure what you are looking for in the way of a 300 blackout. Look into a Tom Denall Silent Destroyer. I have one and it is sweet. He has gotten about 3/4" groups with his barrel modifications. @ 100 yards. I sure am not that good. It is a 44 magnum. He was making them for the PDs. He has some 2 am loads that are very quiet. Made on a Ruger bolt action 44 mag. I heard they were getting tough to find years ago. Not sure if Ruger was still making them. Sweet rifles.

 

[thecolter]

One thing to think about with very short barrels (7-8") is that they may not stabilize the bullets very well. This can lead to baffle strikes with the suppressor. I've seen this first hand with a 7" barreled AR that will not stabilize 62gr bullets, causing them to keyhole and be inherently inaccurate.

As far as being loud, nothing is going to be 'silent'. The great thing about a suppressed SBR is the elimination of the muzzle blast and resulting pressure. I can shoot my 10.3" barreled AR suppressed just fine without hearing protection. You still get the crack of the bullet going supersonic, but the blast isn't there.

 

[Bearclaw]

Thank you guys for all the info. Looks like I have a lot of research to do still and a of money to save up. lol

Is there any range/shop/store around that you can try something suppressed?

 

[Brian Ski]

Is there any range/shop/store around that you can try something suppressed?

Sometimes it is nice to go shooting with a guys that have some. Well you are a ways from me. There is a thread about NFA dealers. See if one is close to you. He may have some inventory or a range.

 

[Wolverine6G]

Thank you guys for all the info. Looks like I have a lot of research to do still and a of money to save up. lol

Is there any range/shop/store around that you can try something suppressed?

Great Idea Profire has several shoots a month at Tims and Parabellum for you to try out several different suppressors on various calibers. Depending on how far away you are give them a call and find out!

 

[GuitarGunman]

Hey Bearclaw,

It was great meeting you at PayLess. INGO swag is a great communicator!

 

[DocJekyll]

Thank you guys for all the info. Looks like I have a lot of research to do still and a of money to save up. lol

Is there any range/shop/store around that you can try something suppressed?

I know this may not be of too much help but if you're ever in the Terre Haute area you're welcome to come out with friends and I and shoot a host of 556 and 300blk suppressed SBR's and other rifles to get a feel for it. I will say though that 556 suppressed really doesn't compare to 300blk at all. Apples to oranges, and since you can reliably cycle 300blk subsonic it makes for an uber quiet package. I was hitting a 10" plate at 240yds pretty easily and it was still beating the steel ragged at that range.

Usually we have one more big range day in the fall where a ton of people come out. I'll see if I can get some info when it's happening but you're more than welcome out here!

 

[chef1231]

So I have a 10.3 inch and was talking with one of the guys over at Griffen today and he said they do not warranty 7.5 barrels because the bullet will most likely not stabilize and you will most likely get baffle strikes. Just thought that might be helpful to some

 

[wsenefeld]

I've put my suppressors on 5.56 barrels as short as 7.5" to as long as 18" and I can tell you from personal experience that all of my suppressors make the rifle sound much quieter when it has a longer barrel.

The shorter barrels will cause significantly more baffle erosion on the blast baffle of your suppressor. No matter what caliber you go with, I'd suggest a muzzle brake for barrels under 16" and either a brake or flash hider if above 16". The muzzle brake acts as a sacrificial blast baffle and will prolong the life of the suppressor. To see these benefits, a 2-3 chamber brake is recommended.

If you decided on a 7.5" barrel, they can be run effectively for home defense. Choose a heavy grain bullet (hollow point or soft point) and you'll be fine. The factory ammo of choice is the 77gr otm or 75gr TAP but it costs a bit more. Regardless of the bullet you choose, it needs to be 55gr or above and the barrel NEEDS to be 1:7 twist. Any slower twist and you'll run a very high risk of a baffle strike. The 1:7 gives you the best chance at stabilizing the bullet and the longer the bullet, the more contact area it'll have with the lands.

While .300 blackout is a great round to suppress, calling it the best is just an opinion. I shoot .223 and .308 but don't have any desire to get into .300 blackout even though I do reload.

Your friend saying that there's no point suppressing .223 honestly doesn't have a clue what he's talking about. I've been able to take 4 coyotes in under 45 minutes and I guarantee I couldn't have done it without my Saker. I'll take any advantage I can get and the advantage of a suppressed 5.56 is pretty substantial.

Personally I would go with a 10.5" or an 11.5" if you choose 5.56. Anybody that says 10.5" is too short needs to realize that when adding a suppressor, you're fixing any issues that might have risen from the minimal dwell time. Suppressors create back pressure and increase bolt speed. With barrels 11.5" or longer, this can be an issue but is easily fixed with an adjustable gas block (not by increasing the buffer weight). Running a 10.5" suppressed won't give you any reliability problems. If you buy from a quality manufacturer, you won't have any problems running the 10.5" unsuppressed.

.300 blackout is an entirely different animal. The goal for most is to run them subsonic and have reliable cycling. To do this, you need the right combination of barrel length, bullet weight, and buffer weight. A heavier buffer will be harder to cycle. That's what you're trying to avoid so use a carbine buffer and standard buffer spring. The longer barrels will give you a more efficient powder burn and increase muzzle velocity. Most subsonic/suppressed shooters prefer 8"-9" barrels for .300 blackout. Lastly, the bullet grain also plays an important part that cannot be overlooked. You can find subsonic ammo with as light of a projectile as 187gr. While these do stay subsonic, they don't create enough pressure to cycle the action. General consensus seems to favor 205gr-220gr with the heavier bullets providing the best consistency.

Hope this helps. It's all opinion and worth what you paid for it. As always, YMMV.

 

[DocJekyll]

.300 blackout is an entirely different animal. The goal for most is to run them subsonic and have reliable cycling. To do this, you need the right combination of barrel length, bullet weight, and buffer weight. A heavier buffer will be harder to cycle. That's what you're trying to avoid so use a carbine buffer and standard buffer spring. The longer barrels will give you a more efficient powder burn and increase muzzle velocity. Most subsonic/suppressed shooters prefer 8"-9" barrels for .300 blackout. Lastly, the bullet grain also plays an important part that cannot be overlooked. You can find subsonic ammo with as light of a projectile as 187gr. While these do stay subsonic, they don't create enough pressure to cycle the action. General consensus seems to favor 205gr-220gr with the heavier bullets providing the best consistency.

Hope this helps. It's all opinion and worth what you paid for it. As always, YMMV.

I've had no cycling issues with 187gr 300blk in the subsonic realms after over 500rds. I've found they have plenty of back pressure to cycle the bolt of an AR-15 type rifle. This is both suppressed and unsuppressed, although for unsuppressed there really isn't anything gained from running subsonic rounds. I did however find that the Gemtech 187 can occasionally pass the sound barrier downrange depending on meteorological factors. (IE air pressure differences between shooter and target). These aren't huge differences but it can be enough for a round that is on the verge of the transonic threshold.

Just what I've seen so far, but I'll continue testing different loads.