View Full Version : Suppressor/barrel length?
I have been reading a lot in the NFA section lately and I have a question regarding suppressor use on short barrels. From what I have read most contend that suppressors should be used on nothing shorter than 10.5" yet in the SBR picture forums on her and other sites I see a multitude of 7.5" barreled uppers with suppressors attached. Is there any specific reason for the desparity between the information and what a lot of people are doing? Can a suppressor be reliasbly used on a less than 10.5" barrel or are there side affects?
JP
I have been reading a lot in the NFA section lately and I have a question regarding suppressor use on short barrels. From what I have read most contend that suppressors should be used on nothing shorter than 10.5" yet in the SBR picture forums on her and other sites I see a multitude of 7.5" barreled uppers with suppressors attached. Is there any specific reason for the desparity between the information and what a lot of people are doing? Can a suppressor be reliasbly used on a less than 10.5" barrel or are there side affects?
JP
Car manufacturers recommend you don't add a supercharger as you'll damage the engine.
What someone does with a product, especially for staged photos of a gun they never shoot, is beyond the control of the manufacturer.
The shorter the barrel the more wear you're going to impart onto the blast baffle of the can. There are also concerns about very short barrels not stabilizing rounds sufficiently and causing endbap or even baffle strikes. Hence the recommendations from the manufacturers, and warranty limitations, re: barrel lengths.
(cue someone to rush in and tell me they have 10,000 rounds on their 5" barrel and suppressor with "no issues".)
I have been reading a lot in the NFA section lately and I have a question regarding suppressor use on short barrels. From what I have read most contend that suppressors should be used on nothing shorter than 10.5" yet in the SBR picture forums on her and other sites I see a multitude of 7.5" barreled uppers with suppressors attached. Is there any specific reason for the desparity between the information and what a lot of people are doing? Can a suppressor be reliasbly used on a less than 10.5" barrel or are there side affects?
JP
As a "general" rule, the shortest barrel that still remains "reliable" is a 10.3. When you start going below that, YOU CAN run into issues (especially when you add a can).
For me, I wouldn't use anything shorter than a 10.3.
C4
I HAVE 5,000 RDS ON MY 5" BARREL WITH NO ISSUES.
:jester:
Eurodriver
01-11-12, 11:42
(cue someone to rush in and tell me they have 10,000 rounds on their 5" barrel and suppressor with "no issues".)
I don't even use a barrel, I mounted my suppressor straight to the chamber.
I don't even use a barrel, I mounted my suppressor straight to the chamber.
Same here! But I got rid of my chamber. I just stick ammo straight into the can!!
I don't even use a barrel, I mounted my suppressor straight to the chamber.
Thanks for making me spew my coffee all over my keyboard
I assume you are talking about 5.56? The shorter gas system on barrels shorter than 10.3" are overrun with a silencer attached more than carbine and longer gas systems.
For shorter barrels 9mm and 300 BLK do just fine, so it's important to include the caliber in the discussion.
Unless another caliber is mentioned I have just always assumed that people means 5.56mm but that's a valid point as there are many AR calibers now.
Thanks for making me spew my coffee all over my keyboard
I almost blew eggs all over mine...
//Break//
Thanks for the info guys, I just wanted to make sure before I did something stupid.
JP
For 5.56, shortening them to 7.5" is almost the 'goes to 11' argument for OAL. Nothing wrong with them, but utility as a fighting rifle starts to really diminish at that point, and usually reliability and can lifetime goes by the wayside as well. IIRC, OPS is the only manufacturer that will warranty a centerfire .22cal for barrels shorter than 10".
Given the fixed length of the receiver, receiver extension, and length of the can, that 3" isn't going to amount to much added maneuverability, coupled with the availability of quality 10.3" and 10.5" setups, that's the generally accepted compact CQB carbine length.
Honestly, if you are going to go shorter than 10.3" on a AR why on earth would you not go with .300BLK? :confused:
I guess some things are just beyond me..... :rolleyes:
viperashes
01-12-12, 00:19
Honestly, you are going to go shorter than 10.3" on a AR why on earth would you not go with .300BLK? :confused:
I guess some things are just beyond me..... :rolleyes:
True. Especially with the price that people are willing to pay for high end ammo like Black Hills TSX, the arguement that 300BLK is too expensive is about moot.
OP, have you actually seen and/or maneuvered with a 10.5" AR? They're fracking tiny with the stock collapsed. With an M4-2000 on the end of that thing, you're only going to see M4 OAL. A 14.5" M4 and a 10.5" with M4-2000 are both right about dead even. Maneuvering an M4, even inside of a vehicle in full kit is not that difficult. If you want to stick to 5.56/.223, stick to 10 or 11" guns.
True. Especially with the price that people are willing to pay for high end ammo like Black Hills TSX, the arguement that 300BLK is too expensive is about moot.
OP, have you actually seen and/or maneuvered with a 10.5" AR? They're fracking tiny with the stock collapsed. With an M4-2000 on the end of that thing, you're only going to see M4 OAL. A 14.5" M4 and a 10.5" with M4-2000 are both right about dead even. Maneuvering an M4, even inside of a vehicle in full kit is not that difficult. If you want to stick to 5.56/.223, stick to 10 or 11" guns.
Nope the shortest I have used is my 14.5" issue M4, my personal M4 at home is also 14.5" with permed FH. I will probibly stick with 10.5"/11" as shortest I'm just trying to figure out things. I tend to ask a lot before I dive into uncharted waters so I don't do something I'll regret.
JP
viperashes
01-12-12, 08:55
Nope the shortest I have used is my 14.5" issue M4, my personal M4 at home is also 14.5" with permed FH. I will probibly stick with 10.5"/11" as shortest I'm just trying to figure out things. I tend to ask a lot before I dive into uncharted waters so I don't do something I'll regret.
JP
At the very shortest, I would go 10.5". I had had thoughts about a 7.5" Diplomat upper at one point, but after actually seeing my 10.5" upper in person, I realized that it was absolutely fracking pointless to go that short. There's not even enough room to really hold on to unless the stock is fully extended.
10.5" guns with a suppressor attached are a really great "fun size" package. If you're worried about weilding a 10.5" stick with a can on the end, other than the weight, you can replicate space requirements approximately by swinging your 14.5" stick around a bit. A can on a gun that short isn't going to add much perceivable weight to the front of the gun.
At the very shortest, I would go 10.5". I had had thoughts about a 7.5" Diplomat upper at one point, but after actually seeing my 10.5" upper in person, I realized that it was absolutely fracking pointless to go that short. There's not even enough room to really hold on to unless the stock is fully extended.
10.5" guns with a suppressor attached are a really great "fun size" package. If you're worried about weilding a 10.5" stick with a can on the end, other than the weight, you can replicate space requirements approximately by swinging your 14.5" stick around a bit. A can on a gun that short isn't going to add much perceivable weight to the front of the gun.
yeah, I get that. I am leaning 10.5" standard upper. This will be my first SBR and I think I'm going to keep it simple. I'll go nuts later if I get/build another. I may/may not get a can I'm just exploring options picking all your brains so I dont dick it up. Probibly going to go 10.5" LMT or Noveske N4 Basic upper once I get my spare BCM lower SBRd. But yeah the Noveske diplomat 7.5 was what cought my eye and made me ask this question.
JP
viperashes
01-12-12, 09:26
yeah, I get that. I am leaning 10.5" standard upper. This will be my first SBR and I think I'm going to keep it simple. I'll go nuts later if I get/build another. I may/may not get a can I'm just exploring options picking all your brains so I dont dick it up. Probibly going to go 10.5" LMT or Noveske N4 Basic upper once I get my spare BCM lower SBRd. But yeah the Noveske diplomat 7.5 was what cought my eye and made me ask this question.
JP
My 10.5" was my first SBR. I've got a PWS MK 110 and love the hell out of it. An LMT or Noveske would treat you well. In all honesty, the lower you're using now, as long as it's quality, which I would assume from your at least 'basic' knowledge of these things (not to be taken as insulting, by any means) that it is, it's worth just doing the Form 1 on it and just forgetting about it for now. That way, you don't have a built up lower that you're sitting around stressing over paperwork for.
The 7.5" guns aren't just novel, but they're just mostly novel. You'll void the warranty on damn near any can you run on it. They almost HAVE to be run suppressed. They don't generally run great suppressed, and a 10.5" or 11.5" will fulfill 95% of any role you want the 7.5" gun to, but with better performance results.
My advice to all that are wanting to 'build' their first SBR is to just go ahead and dish the $200 on your current lower, as long as it's quality, and just forget about it. Building a dedicated SBR lower and just the thought of having that "naked" lower sitting around waiting on paperwork is enough to drive some people bat-shit crazy.
My 10.5" was my first SBR. I've got a PWS MK 110 and love the hell out of it. An LMT or Noveske would treat you well. In all honesty, the lower you're using now, as long as it's quality, which I would assume from your at least 'basic' knowledge of these things (not to be taken as insulting, by any means) that it is, it's worth just doing the Form 1 on it and just forgetting about it for now. That way, you don't have a built up lower that you're sitting around stressing over paperwork for.
The 7.5" guns aren't just novel, but they're just mostly novel. You'll void the warranty on damn near any can you run on it. They almost HAVE to be run suppressed. They don't generally run great suppressed, and a 10.5" or 11.5" will fulfill 95% of any role you want the 7.5" gun to, but with better performance results.
My advice to all that are wanting to 'build' their first SBR is to just go ahead and dish the $200 on your current lower, as long as it's quality, and just forget about it. Building a dedicated SBR lower and just the thought of having that "naked" lower sitting around waiting on paperwork is enough to drive some people bat-shit crazy.
I have a complete BCM lower that I got from Grant last deployment that has no upper for it. So it's not eating at me really I just figured why not SBR that since I have it. Besides if I can work out the trust issue in the next month or two I can file my form one when I'm home on leave in March and by the time my deployment is over mt Form 1 should be back and I can come home and get an upper.
JP
viperashes
01-12-12, 09:40
I have a complete BCM lower that I got from Grant last deployment that has no upper for it. So it's not eating at me really I just figured why not SBR that since I have it. Besides if I can work out the trust issue in the next month or two I can file my form one when I'm home on leave in March and by the time my deployment is over mt Form 1 should be back and I can come home and get an upper.
JP
Understandable. Deployments suck for trying to build these damn things. It's entirely too easy to keep wanting to buy toys for them. I think I ended up buying something close to about 10k rounds of various .223 and 5.56 over the course of the year out here, an SD3G, all kinds of furniture, spare parts, etc. for my SBR. After going through my email and actually looking at my old order reciepts, I was amazed at the money I've spent mostly on stuff for a single rifle. :eek:
Are you planning on getting a suppressor for this SBR at some point?
viperashes
01-12-12, 10:00
Are you planning on getting a suppressor for this SBR at some point?
yeah, I get that. I am leaning 10.5" standard upper. This will be my first SBR and I think I'm going to keep it simple. I'll go nuts later if I get/build another. I may/may not get a can I'm just exploring options picking all your brains so I dont dick it up. Probibly going to go 10.5" LMT or Noveske N4 Basic upper once I get my spare BCM lower SBRd. But yeah the Noveske diplomat 7.5 was what cought my eye and made me ask this question.
JP
OP's last post.
OP's last post.
If I do get one I'm leaning toward AAC. Either a Ranger 2 thread on or a Mini 4. Not sure yet one step at a time. SBR is first, if I can sort that out I'll work on a suppressor for it. Then maybe SBR my other lower, lol. We'll see.
JP
This is probably the best platform to SBR and I recommend this as ones first step into the NFA arena.
With regards to the .223 (5.56) barrel lengths and use of cans, most manufacturers won't warranty under 10.5 or so and that's what keeps most of the guys honest. Once I sbr'd a couple of lowers, I ended up with a variety of configurations. Using Spikes receivers (Punisher) and Noveske SS barrels, I've got a 7.5 with the KX3 "pig" brake and you can't believe just how much it tames the blast and noise. On my 10.5 (with switchblock) I have a YHM SS Phantom and that's very easy on the ears.
Now I will be running a can on my 8.3 HK53 but I don't intend on running magdumps but limited FA will be fine.
The big things to look out for when running the can on the short barrel are:
1) The unburnt powder eroding your blast baffle.
2) The potential that an unstabilized bullet will strike a baffle in the can. You definitely want to match your barrel twist (1:7, 1:9, etc.) to the type of rounds you will be firing. I'm partial to 1:7 with 62 grain bullets.
Whatever you do, get that form 1 in process asap because the delays are running 5+ months now and there is an anticipated surge in forms if/when the CLEO sign-off goes away.
When people talk about using a ported comp to help protect against baffle erosion on an SBR, does using a 2 port comp like the AAC Blackout comp protect any measurable difference better than a single port one like the Brakeout?
viperashes
01-13-12, 04:34
When people talk about using a ported comp to help protect against baffle erosion on an SBR, does using a 2 port comp like the AAC Blackout comp protect any measurable difference better than a single port one like the Brakeout?
I think you have your terminology a little off. The blackout is the flashhider, the brakeout is the combination comp/flashhider, and the brake is just a brake. But to answer your question, conventional wisdom says yes, how noticable? Not sure, I'm sure over time it would become more noticeable. The big thing for me was that I don't care about shooting unsuppressed with a brake, or shooting suppressed with a 10.5" barrel and suppressor. Sure, the suppressor is going to get beat up, but like everything else, it's going to get beat up and wear out eventually. I just don't like the *ping* of the flash hider and brakeout.
The issue with the brake is pretty easy to understand. Brakes tend to have small exit, or through, holes to allow the gasses to build up behind the projectile and exit through the ports. Flash hiders tend to have wider open ends. (I went looking for pics but I can see I'll need to take my own, I happen to have one of each from AAC).
Because of this the metal AROUND the small hole catches more of the hot shit, unburnt powder, etc. Somewhere I believe ADCO has pictures showing the wear that the muzzle brake absorbed which, had the device not absorbed it, would have wound up eating away at the blast baffle instead. I can replace a muzzle device with a vice and a wrench, a blast baffle, not so much.
Here is, at least, a post that shows the wear on the brake.
http://www.silencertalk.com/forum/viewtopic.php?f=2&t=56771&hilit=read
The issue with the brake is pretty easy to understand. Brakes tend to have small exit, or through, holes to allow the gasses to build up behind the projectile and exit through the ports. Flash hiders tend to have wider open ends. (I went looking for pics but I can see I'll need to take my own, I happen to have one of each from AAC).
Because of this the metal AROUND the small hole catches more of the hot shit, unburnt powder, etc. Somewhere I believe ADCO has pictures showing the wear that the muzzle brake absorbed which, had the device not absorbed it, would have wound up eating away at the blast baffle instead. I can replace a muzzle device with a vice and a wrench, a blast baffle, not so much.
Here is, at least, a post that shows the wear on the brake.
http://www.silencertalk.com/forum/viewtopic.php?f=2&t=56771&hilit=read
Rob,
That is good information and the info in the link is eye opening too.
JP
viperashes
01-13-12, 06:08
Good post Rob, and good info in that link.
I think you have your terminology a little off. The blackout is the flashhider, the brakeout is the combination comp/flashhider, and the brake is just a brake. But to answer your question, conventional wisdom says yes, how noticable? Not sure, I'm sure over time it would become more noticeable. The big thing for me was that I don't care about shooting unsuppressed with a brake, or shooting suppressed with a 10.5" barrel and suppressor. Sure, the suppressor is going to get beat up, but like everything else, it's going to get beat up and wear out eventually. I just don't like the *ping* of the flash hider and brakeout.
Yea I said comp instead of brake, but AAC does call their ported Brake and their Flashhider the same thing. "Blackout" That's what I meant.
BLACKOUT™ 51T Muzzle Brake
http://www.advanced-armament.com/product.aspx?pid=728
BLACKOUT 51T Flash Hider
http://www.advanced-armament.com/product.aspx?pid=509
But I do appreciate all the responses. Thanks!
Actually a brake needs to let gasses pass in FRONT of the bullet. This is why a brake with no chamber for expansion won't work....
We found this out the hard way on a Magnum bolt gun with a brake made by a tard.
We found this out the hard way on a Magnum bolt gun with a brake made by a tard.
what was the brake and what went wrong?
It was some aspiring gunsmith's creation. The guy drilled ports with no expansion chamber to allow gas to pass the bullet.
Nothing "went wrong". We just ended up getting our shoulders and rear bag hands battered for several weeks trying to make a magnum caliber bolt gun with a sporter profile barrel group well.
It was some aspiring gunsmith's creation. The guy drilled ports with no expansion chamber to allow gas to pass the bullet.
so it was just a solid piece with a ~1/4" hole through it and vents drilled though it?
Essentially... you know those fudd gun brakes with all the holes spiralling around them.... That type of thing.... but they didn't bore out the brake beyond the bullet caliber enough to create a chamber.
Essentially... you know those fudd gun brakes with all the holes spiralling around them.... That type of thing.... but they didn't bore out the brake beyond the bullet caliber enough to create a chamber.
:eek:
now I know exactly what you mean.
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