Hard as in something will break after prolonged use (gas key or tube)?

Are there adjustable gas systems that replace the gas tube and work with the standard FSB?

Is it a little harder on the system? Yes.

Will it ever really make a difference to one of us? No, we don't shoot enough to wear out a rifle.  

If you shoot suppressed a lot, have a spare bolt and carrier handy, and make sure that your buffer is the proper weight.

Heavier I assume? H3, H4?

Not necessarily on the gas system ie gas tube and gas key. The hard use comes from increased back pressure making the rifle cycle faster and beating itself to death. Think locking lugs, buffers, buffer springs etc...

I don't know of adjustable gas tubes for a standard front sight but a couple companies make adjustable BCG's you can swap from suppressed to unsuppressed.

https://www.silencershop.com/gemtech-5-56-suppressed-bolt-carrier.html

Not so far. First .223 rifle can was purchased in 1992.  Haven't broken anything yet

Yeah, heavier buffers and even stiffer springs like something from sprinco

Flow through cans are less of an issues for extractors, etc but a 5.56 is basically a 22 so there ain’t much breaking going on regardless.

Even if it is there's nothing inside there expensive enough to not put a can on it.  

And even if it was expensive enough unless it wears out in 1000 rounds or something ridiculous I still don't care.

Please elaborate on what isn't breaking.

Ain’t nuthin breaking if the OP is semi auto and suppressed @ 5.56

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22 LR max chamber pressure is 24,000 PSI

.223 Rem max chamber pressure is 55,000 PSI

Well that's an interesting theory.

There are a bunch of bandaids to deal with the extra gas on an AR.  But the only one that actually addresses the problem is restricting the gas at the port with an adjustable gas block or smaller port.  Or reducing the flow restriction in the suppressor, but that isn’t ideal.  It is however a good option for non adjustable gas systems.

A lot of guys prefer heavier buffers/springs or bootleg gas carriers but all they are doing is managing the extra gas that makes it to the receiver.  Doing so just gives you a gassier and/or louder rifle as you vent more gas next to the shooter’s ear.  Some like “flow through” designs but that is inherently less efficient as the gas spends less time expanding/slowing/cooling to lower the energy which is what needs to happen to lower the report.  You want as much gas to go into the suppressor for as long as possible while limiting the amount that gets sent back to the action to the amount needed for reliable operation.

I think too many people take the approach of throwing shit at a rifle because others told them it is needed or worked for them without thinking about the system as a whole.  Because of that they end up causing more new and exciting problems.  I did the same with an LMT enhanced carrier that wasn’t right for the application I used it for and my rifle wouldn’t run for shit.  The AR gas system is pretty simple, but it is designed to operate with a certain amount of pressure for a certain period of time.  If you add/subtract length after the port you affect the amount of time that pressure is applied (same goes for adding a suppressor).  

What you need is going to be unique to your setup.  A 20” AR can have a nice small gas port and give a gently but longer lasting impulse.  While a 10.5” will have a harder impulse that doesn’t last because of the short dwell time requiring a bigger port to function.  Adding a suppressor to the latter means you increased the time pressure is present for that much larger port, so the best option is to shrink that port a bit as you would with a longer barrel.  While adding a suppressor to a 20” is much less disruptive since the rifle is set up for a longer dwell time by default.

-Mike

If the OP is even referring to 5.56 and is also talking about firing a semi auto rifle @ 14.5” then he doesn’t need to worry himself with breaking anything just because he attaches a suppressor. If he’s doing full auto mag dumps suppressed @ 11.5” then he may need to familiarize himself on some stuff.

You could straight up explode between 4 and 10 entire AR15s with suppressors and it would still be worth it

Not if you live in a state thats about to pass an AWB. That includes parts.

depends what you are shooting. with 300blk subs, a standard carbine spring and buffer with suppressor barely works

Then buy one extra AR15 now and if the silencer wrecks the first one, you know to take it easy on the second one.

BRT gas tube.

or get an adjustable carrier. bootleg or gemtech.

@Cowbell , unfortunately that Gemtech carrier is discontinued. The only one I'm aware of on the market right now is the Bootleg Inc one which has worked well for me in reducing MK18 gas to the face with a Surefire RC2.

Ideally you would either shoot a rifle suppressed or unsuppressed. The gas port size, buffer weight, and spring strength are really only ideal for one or the other.

I've got many thousands of rounds using no name uppers, mud tier uppers, and mid tier uppers on various m16 from 7 inch to 20 inch and nothing has broken, yet.

For suppressors and adjustable gas block is best. Yes you an use heavier springs or buffers, but reducing the amount of gas is better.

When I worked at an indoor range the suppressed rental AR was basically a sacrificial lamb. I will say of all the MFG’s we stuck that can on, the LWRC held up the best. Even when the piston was broken in half it still cycled on full auto.

Bootleg makes one too. I have become interested in these as I am starting to get wary about having adjustable gas blocks on a couple of my guns after reading about the screws seizing if you don't baby them. Mine are Superlative Arms so they are supposed to be better, but not invulnerable to carbon locking. My 308 AR works great with full gas suppressed and hasn't had a single hiccup yet, but I can't afford to shoot it much. I'm down to like 300 rounds of ammo left for it.

Why doesn't anybody make a large gas regulator style gas block for the AR that doesn't rely on a small screw with fine threads that can seize and make something similar to the gas regulators on the FAL, ACR, JAKL, SFAR, etc? I know most of those are piston guns, but the SFAR isn't.

To those parts?  Not really.  I’m sure they might see slightly increased wear rates due to back pressure in the system, but I think you’d have a hard time quantifying the difference.  A severely overgassed gun will increase wear on the bolt/cam pin/gas rings and could potentially lead to premature failures.

Adjustable gas is a surefire way to “fix” that issue, but it’s really not an absolute necessity on 5.56 guns.  Vast majority of professional end users of suppressed 5.56 AR pattern rifles do so without adjustable gas because a properly sized gas port will eliminate the vast majority of potential problems.  Low back pressure cans are a part of that equation as well and that’s the direction most organizations have moved (even if they may be slightly louder) with the SF SOCOM RC and now OSS/HUXWRX and Sig flow through designs seeing adoption.

Still, there’s a large enough volume of data on 5.56 AR pattern rifles that it shouldn’t be too hard to set yourself up with a suppressed rifle that doesn’t require adjustable gas regardless of suppressor model/type.

I use a couple of the Bootleg carriers in an 11.5 and 10.5, easy to adjust on the fly.

2 of my 11.5s have smaller gas ports, one is a Sionics reduced gas port and the other is a Triarc Track 2 reduced port.  Even with the Sionics and a Bootleg carriers and a Geissele buffer spring/H2 combo, brass will still eject between 2 and 3 while suppressed.

My Super duty 14.5 without a suppressor (30 cal) will drop casings about 4.  With a suppressor at 1, I even put an H3 to try, maybe 1:30 or 2.  The brass on all only show slight to very slight extractor marks.

My solution, I quit worrying and go shoot.

Black River Tactical makes gas tubes specifically for gas reduction, very nice people, I would check them out, no moving parts to mess with.

There are more than a handful of AGBs that don’t utilize small set screws.  The Noveske Switchblock has been around for a while, and there are a few other cheaper options that offer similar features.  Riflespeed just released an AGB with a large adjustment collar that extends over the barrel and out the front of your handguard.  There are a few others similar as well, although they don’t appear to be as well refined.




As for an AGB adjustment screw seizing, it really isn’t something I worry about, especially with Superlative B/O blocks.  In B/O mode, I set the gun up to run unsuppressed in a relatively cold environment.  This will mean increased pressure when the temps warm up and you add a can, but you’ve usually tamed enough gas out of the system that you shouldn’t suffer any reliability issues, plus the B/O mode should offer a bit of self regulation as the pressure increases, meaning more gas is being pushed through the B/O port.  This method has so far worked on .308, 6.5C, 6.5G, and 6mm ARC without any issues.

I run H2 in all my carbines now.  I used to run H3(actually 9mm buffer) but I had a short-stroke so switched to something a bit lighter.

The Armory/Suppressor sub-fourm here is a great place to check for suppressor info.

Depends on the can and gas port size.  You could also change the buffer spring strength.

Flow through can?  No change to internals needed.  .052" gas port, you need blowback to cycle the weapon.

Breaks bolt catch in my sr25, change to knights armament bolt catch fixed that

High bolt carrier velocity and earlier than necessary unlocking is harder on the bolt and extractor, but with design safety margins an average shooter may never notice premature wear.

Suppressors add dwell but with a milliseconds longer time-flow dynamic than just a longer barrel past the gas port.  Most of suppressor gas in face blowback comes down the bore due to gas capacitance in the suppressor having the suppressor at higher pressure than the chamber/action post-extraction and creating a flow gradient. High flow suppressors deal with the problem with suppressor design and some trade-off on sound.  Depending on use that sound handling may not be a trade-off at all, but high flow suppressors are usually more complex, expensive, heavier, and accumulate fouling faster.

High restriction suppressor blow-down happens in milliseconds after bullet flight so anything to slow extraction reduces the pressure gradient and back flow velocity.  This is best accomplished by throttling gas at either end of the gas tube, versus creating inertia with bolt/carrier/buffer mass and spring resistance.  Venting also works but controlling 3 flows with one bleed point is a tougher balancing act than choking flow in a single path.

An adjustable gas key chokes gas into the bolt-piston/carrier cylinder THEN vents that minor and gas-port-throttled flow path when the key retracts from the rear of the gas tube.  So adjustable gas block is best location for flow control of action-working-gas at the source but is a more challenging location for heat cycling and carbon buildup.

Plenty of solutions of varying cost, complexity, and side effects. They all “work” to some extent and interact with suppressor characteristics and barrel/port constraints making optimum relative to various utility functions (cost, ease of use or install, long term reliability, etc.) an interesting system integration exercise.  Different shooters have different sensitivity to gas and port pop as well.

I also have a Bootleg in an 11.5in SBR with a DeadAir Sandman-K. Quick and easy to adjust, and I haven't had any issues with it.

I like to use the 70k psi HP test loads.

If by standard FSB, you mean an A2, JP Enterprises makes an A2 FSB with an adjustable gas system. It lacks a sling attachment point if that's important to you. Doing an A2, SBR build soon and will be using this.  I shoot suppressed almost exclusively and as a Lefty, I'd prefer extra gas go out the front of the rifle rather than back in my face.  

If you want to bleed even more gas out the front, consider a Superlative Arms adjustable, bleed off gas block.  Rather than pushing all the gas through your suppressor, it vents extra gas directly from the gas block itself which is supposed to greatly reduce blow back towards the shooter and crud in the system. Does it work?  Reviews claim it does, but I don't own one.

This here,  Orrrrrrrrrrr, you can go with the superior PISTON AR design and ditch the antiquated DI...

{Autistic screeching level increases}

H2 JP silent capture spring system smoothes things out nicely. Zero issues with a 16" rifle.
Gets rid of the "twang" as well when the bolt rides home.
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Duke

I broke a gas ring on a 350 legend gun with fairly low round count.  Only time that has occurred to me, I assume it was very over-gassed.

I have about 6k through a heavy gassed mk18 that has never not had a can on it…. So I’m going with no.

Add weight to their normal offering as a can with blowback ejects at the 1 oclock with the H2 JP.  Good for 16", but suppressed SBRs it's not enough.

https://geissele.com/super-42-braided-wire-buffer-spring-and-buffer-combo-h2.html

All the new hotness lengths not addressed. . 12.5", 13.7", 13.9".  Good starting point here.  I personally like the gas length transition to mid at 12.5"

This is accurate.

Nice thing about JP, you can plug and play with different weights/ spring rates using the builders kits and assemble a buffer tuned to your rifle exactly.
All without screwing around with gas settings.
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Duke

No love for guys that want to suppress an 18"+ rifle?

I'm guessing the rifle length gas system solves the problem by itself?

Having a full adjustment at the carrier is nice, vs a "Switch." The 2A RBC is fully adjustable, and I have been able to get it to be light ejecting, but not short without a suppressor, and just slightly over gassed with a suppressor, but not punishing the system over gassed.

The excess gas at the carrier key is vented out under the handguard through the clover leaf as a majority when the key unseats, vs through the carrier from what I found.

Use what runs.  I shoot with a can on a half dozen rifles, most with H1 or H2 buffers, whatever they came with.  I shoot a bit more than average.  All I have ever managed to wear out is a few sets of gas rings.  


Don't go changing a bunch of shit if your rifle runs reliably.  Don't get wrapped around the axles about ejection pattern.

I don’t like the recoil impulse with heavy buffers.  Seems to have noticeably more recoil with the extra reciprocating mass in the system.

I like the bootleg carrier since it’s a drop in part and I can get good ejection with a carbine/H1 buffer. If I shot primarily left handed I would go with an adjustable gas block.

QFT

Just so it’s known but bushmaster made adjustable gas tubes back in the day.  They are completely unobtainable today but they do exist in the wild.  If I had an account I would post evidence.

Edit. Not asking for a handout membership lol