View Full Version : Do suppressors heavily impact reliability?
Vapor Trail
05-04-12, 17:29
I was wondering if anyone has had serious issues when running a can. Doesn't it change the amount of gas required to cycle the action? I know Noveske has their switchblock thing, and a lot of piston rifles have multiple gas settings, but other than that is there anything you can do? Or is it kind of a non-issue anyway?
It can greatly increase gas pressure going into the BCG and raise the cyclic rate. It can be mitigated by using heavier buffers, fatboy gas tubes, enhanced carriers, or custom sized gas ports. If you start dicking with any of those "solutions" be prepared to do lots of testing and troubleshooting.
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I haven't had any issues with mine on a stock 6920. It does throw a lot of gas out of the action though.
It can depends on the system. In an AR type, it can be if you don't have other correct pieces, like springs, buffers, and gas system.
I run an LMT 10.5 with thunderbeast 30BA with my reloads, brown bear and wolf with no problems what so ever. Have read they cause problems with others tho.
Suppressors extend the time that the gas system is powered and effectively make it "over gassed".
The effect is similar to having too large of a gas port.
It reduces the reliability of the system and can leads to all kinds of issues.
The switchblock (http://www.noveskerifleworks.com/switchblock/) page actually explains is beautifully and has a video.
In the video, notice the direction of the ejected cases in each of the tests.
My experience with suppressors is the mil issue KAC NT4 on a Colt M4. The only malfunction I've had with this setup ( keep in mind that with a mil issue weapon I wasn't able to change buffers or buffer springs or adjust gas settings ) was after firing 480 rounds ( 16 30 rds mags ) during a training session, the bolt started acting sluggish and FTE'd twice. After a quick spray of SLIP2000EWL it shot another 5 mags ( 150 rds ) that day without issue.
Using the same setup named in the post above mine, as well as a suppressed SR25 the only issues I've had is that it gets dirtier sooner. Same for the M110. All I do is do a quick wipe of the BCG and upper more often, and apply more lube.
Vapor Trail
05-05-12, 01:29
Suppressors extend the time that the gas system is powered and effectively make it "over gassed".
The effect is similar to having too large of a gas port.
It reduces the reliability of the system and can leads to all kinds of issues.
The switchblock (http://www.noveskerifleworks.com/switchblock/) page actually explains is beautifully and has a video.
In the video, notice the direction of the ejected cases in each of the tests.
I assume this issue is made even worse when utilizing an SBR or similar platform, like a 7.5" with a pistol-length gas system? I've heard that the smaller you get, the more issues a DI rifle will have.
justlikeanyoneelse
05-10-12, 02:42
Don't worry too much about it, unless your running into initial mechanical problems, suppressed weapons are pretty reliable. Just be sure to clean like no other, shit gets into places you didn't know existed...personally run a sbr suppressed and I could finger paint the mona lisa with all the fouling. :lol:
viperashes
05-10-12, 04:13
Don't worry too much about it, unless your running into initial mechanical problems, suppressed weapons are pretty reliable. Just be sure to clean like no other, shit gets into places you didn't know existed...personally run a sbr suppressed and I could finger paint the mona lisa with all the fouling. :lol:
This. Even with a piston gun, carbon fouling is pretty crazy with a suppressor. The thing is, the carbon isn't just entering the receiver through the gas system, its also entering through the chamber when the bolt unlocks earlier than normal.
There's going to a lot of variables when shooting any gas gun. Adding a suppressor is just another variable. Find what your gun likes and stick with it. That's the best way to have a reliable AR imho.
For what it's worth, I've run a can on 3 different 16"ers and didnt see a noticeable difference in operation with or without a can. My 11.5" SBR does need it to run though.
I have multiple guns, multiple suppressors, all different barrel lengths, different H2, H3 A5 . No problems, all different kinds of ammo. It obviously causes some people problems?
Not me so far.
I assume this issue is made even worse when utilizing an SBR or similar platform, like a 7.5" with a pistol-length gas system? I've heard that the smaller you get, the more issues a DI rifle will have.
This is my understanding.
IMO, the primary reason SBRs have issues is the relatively short travel of the cam pin does not provide a great deal of delay time before extraction starts.
The original rifle length gas tube provided a "gas delay" on top of the cam track delay.
The combination of the two is enough to allow the case to contract and make extraction relatively easy in the rifle length system.
Short gas systems cut down the gas delay, making extraction more difficult.
Suppressors hold up the chamber pressure longer, compounding the problem.
Also, I view reliability in terms of reliability MARGIN.
How much room for variables is there before a malfunction occurs?
A weapon may be 100% reliable running mil-spec ammo while clean and dry.
What about low power ammo while cold, wet and dirty?
The Best Suppressed SBR Ever??? (https://www.m4carbine.net/showthread.php?t=33743) thread is a good 15 page read too.
It's enough of a problem with my SLR-106 (5.56 ak) that I'm looking for a way to restrict the gas.
When I first put the can on, I had problems with bolt speed being too fast. I think the carrier assembly was moving rearward very quickly and harshly rebounding off of the rear trunnion so that it sprang back forward with more energy than normal. The ejection pattern was definitely different, with brass being thrown to around 1:00.
Some combination of the extra velocity when moving rearward (perhaps knocking the rounds in the magazine downward more than usual) and the harsh bounce and quick return off of the rear trunnion was causing bolt-over failures- I'd find a round pushed half way out of the magazine, but with the bolt head resting somewhere on top of the case wall instead of behind the case head. This was happening with some frequency- maybe once every 4 mags or so.
I gained an improvement in function by installing a Wolff "+" recoil spring, which must have delayed the bolt carrier enough to allow the magazine spring to keep up.
I'm not completely happy with this solution, however, as I worry the locking mechanism is still unlocking more violently than needed and incurring more wear than necessary.
The rifle's insides become absolutely filthy and some gas is blown through the take down button hole into the shooter's face, though it's not quite as bad as a 16" bbl AR.
I'm considering drilling and tapping a hole in the gas block and adding a stainless set screw which could be adjusted for function and then held in place with safety wire.
You cannot compare suppressing an AK47 and an AR rifke or carbine. AK's have their own unique issues due to the operating system, port sizes among other things.
It's enough of a problem with my SLR-106 (5.56 ak) that I'm looking for a way to restrict the gas.
When I first put the can on, I had problems with bolt speed being too fast. I think the carrier assembly was moving rearward very quickly and harshly rebounding off of the rear trunnion so that it sprang back forward with more energy than normal. The ejection pattern was definitely different, with brass being thrown to around 1:00.
Some combination of the extra velocity when moving rearward (perhaps knocking the rounds in the magazine downward more than usual) and the harsh bounce and quick return off of the rear trunnion was causing bolt-over failures- I'd find a round pushed half way out of the magazine, but with the bolt head resting somewhere on top of the case wall instead of behind the case head. This was happening with some frequency- maybe once every 4 mags or so.
I gained an improvement in function by installing a Wolff "+" recoil spring, which must have delayed the bolt carrier enough to allow the magazine spring to keep up.
I'm not completely happy with this solution, however, as I worry the locking mechanism is still unlocking more violently than needed and incurring more wear than necessary.
The rifle's insides become absolutely filthy and some gas is blown through the take down button hole into the shooter's face, though it's not quite as bad as a 16" bbl AR.
I'm considering drilling and tapping a hole in the gas block and adding a stainless set screw which could be adjusted for function and then held in place with safety wire.
You cannot compare suppressing an AK47 and an AR rifke or carbine. AK's have their own unique issues due to the operating system, port sizes among other things.
^^ Can you elaborate please?
How is the AK fundamentally different than the AR?
Iraqguns would be the expert, he's spent a lot of time working on them.
I fail to see how there is no comparison in this case, however. The solution to problems with DI rifles and piston rifles is restricting gas until the carrier moves at roughly the same speed as it did unsuppressed. Sure the gas impulse and duration are different when adjusted like that, but the energy with which the bolt assembly unlocks and then travels is what matters, right?
I merely meant to point out that my AK has the same issues for roughly the same reasons as a DI rifle: timing issues (to name only one).
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