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I completed a 6.6G build with a factory built 18" PSA Stainless Steel barred upper with a rifle length gas tube. I was looking at the adjustable their profile gas tube and removed the tiny gas adjustment hex locking screw. Now, I can no longer get the small hex screw back in.
I want to replace this low cost and finicky low profile PSA gas block.
(1) Given I will shoot 123gr Hornady SST with a standard A2 rifle stock and buffer, do I really need and adjustable gas block?
(2) If I do need an adjustable gas block, is the Superlative Arms adjustable clamp-on a good choice (I need to go clamp-on as the current gas block has only 0.300" center to center set screws)?
(3) Any other comments or suggestions are welcomed.
Thanks in advance.
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You should be OK without an AGB.
That said, for suppressors and the fine tuning that is typical of a gun forum most prefer to be able to tune their guns to be the most efficient they can be. In some cases it is overkill, while in others it is necessary and should always makes things better.
Unless the set screw block is a super tight fit you might find it is a less efficient seal than a clamping design. Even with a bit of gas leak it should still be OK however. SLR's Sentry series is well respected on this site.
With an AGB it pays to crack the carbon that builds up after every shooting session by screwing the small adjustment screw in and out. Otherwise carbon builds up and it eventually freezes in place. Not the end of the world if that happens but you might need to pull it off and apart.
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The first thing about Adj. GB's are that they can be clamped on, which eliminates gas leaks, then there's the fact that you don't know what you might want to do with your builds down the road. Better to have and not need than the other way around.
I like this company for several reasons including price plus the hole at the top allowing proper alinement.
https://www.wojtekweaponry.com/
"Wild flower, growin' thru the cracks in the street" - Problem Child by Little Big Town
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No, adjustable gas blocks are not needed. As Klem says, they only really show up as needed if you are running surpressed, due to the odd gas pressure curve you get there. Otherwise, no - so long as the gas port isn't cut goofy-wrong (it usually isn't), then no, you don't need an adjustable block.
As to gas block leak, I've seen lots of guns leak a lot around the block, and some not at all. Never seen it to actually matter.
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lazyengineer Wrote:No, adjustable gas blocks are not needed. As Klem says, they only really show up as needed if you are running surpressed, due to the odd gas pressure curve you get there. Otherwise, no - so long as the gas port isn't cut goofy-wrong (it usually isn't), then no, you don't need an adjustable block.
As to gas block leak, I've seen lots of guns leak a lot around the block, and some not at all. Never seen it to actually matter.
There are several/many reasons to use an Adj. GB including limiting recoil thus while no, an Adj. GB isn't necessary to the operation of an AR unsuppressed, it still has other uses. As for gas leaks, while they may not matter to you they surely matter to some or the subject would have never been addressed by people in threads.
"Wild flower, growin' thru the cracks in the street" - Problem Child by Little Big Town
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Adj gas blocks work if the gas system is over gassed or has excessive dwell time.
Adj gas blocks will leak more gas than a non adj gas blocks, more openings for gas to leak out..
If your rifle system is under gassed, the adj gas block is pointless, it can only restrict the available barrel gas port pressure, not increase it.
If your rifle system is over gassed, (as many are) then an adj gas block is a great way to tune the rifle's gas system.
Suppressors increase dwell time, not port pressure..This means the system stays charged longer and an adj gas block can help tune the system..
If a rifle is over gassed, some try to use the buffer-spring method to mitigate excessive recoil.. This method can work if the gas port is not excessively over sized.. For best recoil mitigation, the advantages of balancing the gas and recoil-buffer together gives the best results.
All adj gas blocks require maintenance or carbon lock will occur, all of them. Putting a little oil on the adj screw and screwing in and out will keep the carbon at bay. All screw choke adj types will have the screw ends deformed and cut with use. Most cases all it takes is to screw the adjuster in a little more when this occurs, but sometimes it requires the replacement of the adjustment screw..
It is advised not to use adj gas blocks with any 5.56 pistol length gas tubes as the adj gas block design is weaker than a solid gas block and will eventually self destruct "break apart" under the high port pressure..
