LMT e-carrier, Vltor A5H4 buffer, Sprinco Green spring, and whatever gas settings work with that combo.
I did this mod while waiting for the suppressor, so I cannot speak to shooting suppressed without it.
Cheap and easy, might as well give it a shot.
http://www.03designgroup.com/technotes/do-it-yourself-gas-buster-charging-handle
Can the attitude slick. You asked what works and I told you, SLR’s.
Insulting someone who was trying to help instead of simply ignoring the post belittles yourself not me.
It may not help compared to an AR properly ported to run suppressed, but it’s much better than running a suppressed AR that’s over gassed. And if the LMT carrier will run on less gas and opens the bolt even a fraction of a second later, the shooter can take full advantage of an adjustable gas block
My observations over the years seems to indicate that the when using different cans is that the amount of gas drive to the action system and blowback of fouling in different cans are not the same. Cans can produce many different attributes besides sound quality. Some cans blowback more without needing as much in a change in action system weight to maintain the balance of operation. I would tend towards looking at a sound suppression systems with a lower degree of lower pressure fouling coming back, given the same or similar span of operation. That is as long as it doesn’t hamper the duration or span in function of a particular setup.
The lower pressure blowback can’t be eliminated with current technology, but there are some things that can be done to reduce that in the commercial market.
I can. I put a Syrac Gen II .750 on a 11.5" barrel with a .073 gas port. After approximately 200 rounds through the gun with a 556-SD suppressor I noticed that the detent screw was spinning freely. I attempted to apply solvent to the threads and vent port but this did no good. At that point I attempted to contact Syrac customer service through their website but was ignored. This was only the most recent episode of Syrac ignoring my attempts to obtain customer service. They seem from my experience to have a bad habit of not picking up the phone or answering emails, which is an unfortunate outlier in the current market. I took the block off the barrel and tried to clean it, but this was futile. At that point I felt I had to diagnose the problem myself. I knocked the pin out of the port and found that the spring was fused in place with caked fouling. I was able to remove the spring after a soak in some solvent and scraped the fouling loose, but was unable to recover the detent. I carefully backed the screw out, but still could not recover the detent. I really do not understand what could have happened to it because I certainly was not being Cavalier when I backed out the screw. Perhaps it was lost in the caked fouling? This is basically irrelevant, though, because I would never trust this device again after such a troubling premature failure.
I replaced it with a SLR Sentry, which so far has worked as advertised and in my opinion should be much less prone to this kind of failure given the design. SLR even replied to my email within an hour when I asked a question.
This experience has left me with a $100 paper weight. Caveat Emptor.
I cannot say enough good about SLR’s customer service. I had a gunsmith mangle a Sentry during a refinishing job and SLR went above and beyond to replace components at no cost even though it had nothing to do with them. They even payed the shipping.
I think SLR and Syrac are good companies with good cs, but I had failures with adjustable blocks from both. I’ll try to post more later but IMHO screw adjusters just aren’t the right design for reliability. These products serve a certain market and purpose but personally I wouldn’t rely on them if reliability is a priority for the gun.
Syrac. Best damn CS.
Failed?
How can a Syrac gas block fail?
With any adjustable gas block, the adjustment mechanism will lock up due to carbon fouling and require soaking/cleaning to restore operation. Of course, once the right adjustment is found, most never change the settings.
Detent siezed and adjustment screw no longer had detents to hold the adjustment. So the adjustment could move on it’s own and it was hard to set the adjustment without detent clicks.
Or if the adjustment in on the rear of the block. Much easier if it’s on the front.
I wouldn’t consider a maintenance issue as a failure of the part. I hit my adjustment screws with a drop of Kroil before and after each use and my Syrac’s have never locked up.
I’ve had 6 Syracs and each one locked up solid. The ones on the suppressed guns didn’t make 1000 rounds before they were done. Don’t get me wrong, it’s a well made block but if you’re putting more than 100 rounds in a session through the rifle, it will not last. It definitely won’t make through a class without locking up.
I use SLR blocks in all our builds. A little SLiP2000 EWL on the adjustment screw and it will be free. They recommend when you clean the rifle to run the screw closed then back open to its prior position. That will help to keep it free.
The big deal with AGBs is where the gas you cut off from going back into action is vented. Everything good thing has consequences. The SLR provides for this and the Syrac does not. Consequently, that gas goes into the Syrac’s mechanism causing it to foul up and seize in short order especially since the Syrac has such a fine adjustability. The SLR has a more coarse adjustment mechanism that handles this fouling better.
If you plan to set it and NEVER move it, a Syrac or other Swiss watch type block might work…but if you EVER MIGHT change it (think about changing ammo in a pinch), then get a SLR. It’s a very well thought out and well made block.
I shot 1000 rounds through my suppressed 10.3" last week without cleaning the rifle and the adjustment screw is as free as the day I installed it.
Disclaimer: no affiliation with SLR but I’ll never by another brand AGB again…EVER.
Just sayin.
A buddy of mine played with the adjustable gas keys also. I’m not sure that playing with the system on the low pressure end is any better. He shot several thousand rounds through them with mixed results. The major problem was getting the screws to stay set even with loctite.
I’d honestly go with a block over a key. To me, adjusting on the high pressure end lends to more reliability and less gas physically going into the action (even if it lingers in the barrel and chameet, it ain’t moving), less carrier velocity and less gas in the face. Adjusting on the low pressure end lends to the need for a minute adjustment or maladjustment that can make a huge difference in reliability.
The upside to a block over a key is that you can choose the buffer and spring that YOU want and tune the gun to it, especially suppressed. My MK18 shoots like a friggin wet dream instead of an over gassed beast that I had to buffer and spring down.
YMMV.
Too bad pws hasn’t made a DI version of their piston adjustable. gas block. That thing is pretty slick. Never frozen, and easy to adjust.
Not that it really helps, just talking outloud and to myself.
Pre treating the screw with FireClean goes a LONG way toward that end.
With the Syrac blocks, I treated them all with Frog Lube prior to use then reapplied intermittently. No joy. I know FL and FC are not the same but still similar. As always, YMMV.
I’ve seen a couple get pretty damn difficult to move (including my own). Ended up bending the nipple on the adjustment tool…