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Adjustable BCG vs Adjustable Gas Block
- Thread starter wastedtalent
- Start date
OK, so here is more fuel to the fire:
The simple physical properties of both components seems to make 1 thing stand out to me as far as functional reliability in a high-use rifle. The AGB reduces the amount of gas entering the upper receiver to operate the BCG. The ABCG limits the amount of gas already in the upper receiver from operating the bolt within the BCG.
Based on the above assumptions, what happens to the excess gas in the ABCG that is not used and expelled thru the BCG side ports? Does this excess gas end up as additional fouling inside the receiver? On the same note, as carbon buildup fouls the AGB, it tended to under-gas the upper and you get short-cycle FTFs. It seems to me that using a combination of the 2 mechanisms can be beneficial. Using an AGB can mitigate the excess gas entering the receiver to a certain point where the ABCG can increase dwell and retard bolt unlocking.
I have yet to run an ABCG, but have run PRI, SLR and Superlative AGBs. I haven't had on seize, yet, but am not running 1000s of rounds thru them between cleaning. I do have their settings in my Weapon Record Books for each rifle and will remove adjustment screws and clean internals with good ol' #9 and a long pipe cleaner along with the gas tube every deep cleaning of the rifle.
The simple physical properties of both components seems to make 1 thing stand out to me as far as functional reliability in a high-use rifle. The AGB reduces the amount of gas entering the upper receiver to operate the BCG. The ABCG limits the amount of gas already in the upper receiver from operating the bolt within the BCG.
Based on the above assumptions, what happens to the excess gas in the ABCG that is not used and expelled thru the BCG side ports? Does this excess gas end up as additional fouling inside the receiver? On the same note, as carbon buildup fouls the AGB, it tended to under-gas the upper and you get short-cycle FTFs. It seems to me that using a combination of the 2 mechanisms can be beneficial. Using an AGB can mitigate the excess gas entering the receiver to a certain point where the ABCG can increase dwell and retard bolt unlocking.
I have yet to run an ABCG, but have run PRI, SLR and Superlative AGBs. I haven't had on seize, yet, but am not running 1000s of rounds thru them between cleaning. I do have their settings in my Weapon Record Books for each rifle and will remove adjustment screws and clean internals with good ol' #9 and a long pipe cleaner along with the gas tube every deep cleaning of the rifle.
Didn't crabs get banned in the last thread like this? More baseless BS from a know-nothing internet tough guy.
Guy, the reason those manufacturers don't use AGBs is they spec the ports based on use case and end user request. Civilian gas port? Big enough to run Tula with no lube dirty. Now throw on a traditional suppressor. Even with an H3 and a Sprinco suddenly its "why is my AR not running right?"
Or if they spec them small like KAC, its "why can't my $2500 rifle run Wolf steel cased?"
AGB lets you do both and then some. Show me a current gen SLR or Superlative or Seekins breaking in the wild in the manner in which you describe. I'll wait. You can find EVERYTHING breaking on the internet, including LMTs, KACS, BCMs, Colts, etc. LMT has a bad heat treat on bolts and they start shearing lugs, you name it. But those gas blocks? Very few and far between and usually some kind of manufacturers defect like the bad heat treat etc.
You sound exactly like those people who said no optics on their rifle cause they just break unlike irons years ago. Now they are standard issue. No one is saying you need an AGB on every rifle, no one is saying give them to every grunt (they have the luxury of being able to spec the gas ports for way less ammo types and only one or two kinds of suppressors, buffers, etc). The point here is that there are a current crop of dead nuts reliable adjustable gas blocks. You not liking that fact doesn't make it untrue.
Guy, the reason those manufacturers don't use AGBs is they spec the ports based on use case and end user request. Civilian gas port? Big enough to run Tula with no lube dirty. Now throw on a traditional suppressor. Even with an H3 and a Sprinco suddenly its "why is my AR not running right?"
Or if they spec them small like KAC, its "why can't my $2500 rifle run Wolf steel cased?"
AGB lets you do both and then some. Show me a current gen SLR or Superlative or Seekins breaking in the wild in the manner in which you describe. I'll wait. You can find EVERYTHING breaking on the internet, including LMTs, KACS, BCMs, Colts, etc. LMT has a bad heat treat on bolts and they start shearing lugs, you name it. But those gas blocks? Very few and far between and usually some kind of manufacturers defect like the bad heat treat etc.
You sound exactly like those people who said no optics on their rifle cause they just break unlike irons years ago. Now they are standard issue. No one is saying you need an AGB on every rifle, no one is saying give them to every grunt (they have the luxury of being able to spec the gas ports for way less ammo types and only one or two kinds of suppressors, buffers, etc). The point here is that there are a current crop of dead nuts reliable adjustable gas blocks. You not liking that fact doesn't make it untrue.
You mean like HRT or JSOC guns that run suppressed 100% of the time yet are not using custom ports or AGBs?
I have forgoten more about this subject than will ever know.
Boom Goodnight sweet child.
Wouldn't working the AGB every so often take care of the seizing issue? AGB's are basically a course needle valve. Early engines had in the manuals to adjust the needle valve so often to keep them from seizing.
This block seized up at some point over the course of a barrels life. About 15k rounds. No idea exactly when because I never adjusted or cleaned it. It technically "failed" in that it was no longer adjustable but never caused a malfunction.
Put it on a new barrel and snapped the adjustment screw right off but the gas setting was about right for the new barrel. Ran it another 13k+ rounds with no cleaning and obviously no adjustment.
I can shine a light in the port and it's clean as can be with no obstructions or fouling buildup. This part of the system is self cleaning and doesn't really need any maintenance.
Crabs can turn any thread into a dumb thread. Notice how he could provide absolutely NO EVIDENCE to support his claims when asked. He just defaults to "hurr durr SOCOM JSOC" like most larpers, EVEN AFTER it has been explained to him that of course they would not need (in most cases) an adjustable gas block since they are running only few types of ammo on low back pressure suppressors (not to mention the same buffers+springs etc.) and they can instead just spec the gas ports correctly from the factory for those narrow uses. It is willful ignorance at best.
I told you exactly what happens but you either choose to ignore what is convenient or your reading comprehension is around that of a potato.
I was building guns with AGB's probably before you even knew what end the bullet comes out. For a while I was building about a dozen guns a week with switchblocks, so much John had to cut me off because production couldn't keep and and most were going on guns destined for overseas. Guys like Wes were building alot of contract uppers at the time for various orgs and personal purchases. Getting noveske parts at the time (they were the best of that era) got very difficult. Point is, some of us have built more guns with ABG's than guns you have ever laid eyes on.
Again, Novices trying to talk shit to those who been doing it their whole lives. You think because you can slam some lego parts together you know what your talking about.. L O L. You don't know jack shit.
I don't see any of those makers using your preferred adjustable carrier key either......Or does your argument apply only to gas blocks ?
Go read the name of this thread.
And then go read this entire thread.
And then think about your post and why it is fail.
This is my last post here.
I've been off the forum for a year and must've missed some stuff. Did Centuriator get banned and return as crabs? Seems about the right level larp. Not quite as vulgar as Primus so I don't think its him.
It was a simple question- can you give a non evasive answer ?
The OP asked about which was preferable, you railed against the adjustable gas block citing failure/seizing etc, arguing that if they were good then you'd see them on "hard duty rifles" as you listed.
So, If the ABCG is a better gas control solution ( and you say the operators are knowledgable enough not to tard out on them), then when do they not come on "hard duty rifles" either ?
Internet tough guy larping BS is why people leave this site, crabs being a prime example here. Again, offers no evidence of any of his claimed failures on any of the gas blocks mentioned, just a load of the same hot garbage. "i bUiLt RiFleS 20 yEaRs aGo aGb SuCk! No i cannot support my claim but SOCOM!!!!!!!"
Lets see if he keeps his promise to stop cancering up the thread.
Lets see if he keeps his promise to stop cancering up the thread.
centuriator; now there was an instigator! lol
I've never seen so much passion over gas blocks.
I have 0 experience with them (agb).
I'm honestly curious about the failures as well. Mainly over how many rounds, were the users following the manufacturers recommendation to back out and reset the adjustment screw every so often (at least that is what mine says to do), maybe a drop of oil every now and again, and what exactly constitutes failure? As some have asked, was failure just that the adjustment screw locked or was it a total weapons failure (ie failure to feed, extract, etc.)? I don't know if that was even answered.
This thread seems to be representative of the Hide as a whole as of late. We have people with legitimate experience but an otherwise productive conversation turns in to a shit fit between grown ass adults.
I have 0 experience with them (agb).
I'm honestly curious about the failures as well. Mainly over how many rounds, were the users following the manufacturers recommendation to back out and reset the adjustment screw every so often (at least that is what mine says to do), maybe a drop of oil every now and again, and what exactly constitutes failure? As some have asked, was failure just that the adjustment screw locked or was it a total weapons failure (ie failure to feed, extract, etc.)? I don't know if that was even answered.
This thread seems to be representative of the Hide as a whole as of late. We have people with legitimate experience but an otherwise productive conversation turns in to a shit fit between grown ass adults.
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Based upon my specific purpose of the build, I'll run the system with the AGB, Bootleg, and gas buster charging handle. If it seizes, oh well. I'll run the block so that if the Bootleg fails - in it's entirety - I'll switch it out for a backup BCG that I keep with that load out. The plan will be to run slightly over gassed for reliability's sake with less parts abuse. I'll have to run it for a couple thousand rounds this way, but I'll report back with my findings (if for nothing else, to resurrect this fantastic thread).
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None at all. The gas port is still round and the tip of the adjustment screw appears intact.
Hk416A5 has adjustable gas.
The first adjustable gas system I ever saw for the AR-15 in production was from JP, about 20 years ago. Some LR shooters using PPC-based AR-15s back in the day had Gerry-rigged AGBs, but I don’t recall anyone before JP producing one.
The #1 driver initially for AGBs on AR-15s was 3-Gun. The second was for precision rifles.
Then we started to see this trend where people with cyclic-rate issues tried to address them with adjustable gas, which may or may not be the ideal choice. (Some gas ports are just too large and do best with a bushing installation/smaller port in the gas block vs a threaded screw impeding into the flow path at a 90˚ angle.
Every single after-market AR-15/AR-10 adjustable gas block I’ve used or have worked on was carbon-welded/seized.
I personally really like the Bootleg carriers now for suppressed use.
I’ve also played with the Sun Devil Adjustable Gas Key, never seized.
One thing I’ve noticed with some AGBs is that due to the additional holes in the block, you need to let them carbon-fill the crevices before setting the gas with whatever load you’re using.
It brings up another issue in that most of the DIY builds don’t have the correct fitting of the gas block to the journal because this usually requires a press-fit jig/fixture in a shop to get proper seal. There shouldn’t be gas leakage coming out from the block and barrel, but you see it as a rule with DIY builds involving the low-experienced layman sliding gas blocks onto barrels with ease.
It’s one of the reasons why I bed my gas blocks, in addition to improving accuracy by deadening the resonant dissonance between the block and the barrel. I hand-select my blocks from a larger pool to get the kind of fit I’m looking for, so smaller ID blocks that require a press-fit will always provide a nice seal that will never open with the different coefficient of thermal expansion between whatever barrel steel and gas block steel is used.
When talking about “over-gassing”, people might recall that US TDP/Mil-Std spec blasters have to demonstrate reliability in Arctic conditions, as well as high temps/high sand/dust. People that live below the frost belt or at lower altitudes don’t ever see extreme cold temps, so it isn’t on most of their radars, but it definitely is for the military.
Right now, I think the Bootleg ABC would make an ideal solution to the Mil guns, as well as suppressed.
Would also provide 90% or more of the benefit of a fully adjustable block for a race gun without messing with fine-tuning and carbon-welding.
This isn’t a knock on any of the several reputable companies that make ABCs, just my perspective on the subject after chasing these rabbits since the 1980s.
Based upon my specific purpose of the build, I'll run the system with the AGB, Bootleg, and gas buster charging handle. If it seizes, oh well. I'll run the block so that if the Bootleg fails - in it's entirety - I'll switch it out for a backup BCG that I keep with that load out. The plan will be to run slightly over gassed for reliability's sake with less parts abuse. I'll have to run it for a couple thousand rounds this way, but I'll report back with my findings (if for nothing else, to resurrect this fantastic thread).
Sounds like the smart way to go, IMO. I doubt you’ll ever see the Bootleg carrier fail; although anything mechanical can fail, it’s a pretty robust system without much to go wrong. If it ever does have an issue, I think it’d be from carbon seizing of the adjustment, same as some are concerned about with gas blocks. (If it helps put some weight behind that - my career is in testing mechanical parts and systems like this, and part of that is identifying weak points and failure modes ahead of time, so this isn’t just random guessing.)
Also, I apologize to the group for my part in starting up the argument with Crabs. I’d forgotten who he was until after I’d posted, and should have handled that more indirectly. I don’t mean to imply that he’s right, just that it’s not worth trying to reason with him.
Just stumbled upon this old gem again. Thought I'd bump it so others could enjoy the retardation.
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