What is your guys go to for adjustable gas blocks? I just finished building a 20 inch SPR style rifle that is definitely over-gassed with a suppressor on it. The rifle is going to be ran suppressed 98% of it's life. So I figure I can throw an adjustable gas block on it tune it to my load and be done with it. This is my first venture into building a "precision" gas gun.
- Thread starter cdeiglmeier
- Start date
Do you have the SLR 7 series? I've been looking at those
After all the issues with carbon-welding an AGBs, I tried the Bootleg Adjustable Carrier and see it becoming my go-to carrier for the foreseeable future.
You adjust the gas settings through the ejection port with a flat head, too easy. Perfect for suppressing so far, and I can see the difference on my brass between the unsuppressed setting vs suppressed.
You adjust the gas settings through the ejection port with a flat head, too easy. Perfect for suppressing so far, and I can see the difference on my brass between the unsuppressed setting vs suppressed.
I switched over to superlative arms earlier this summer and have been very pleased. Their adjustable gas block functions a bit differently. Instead of restricting gas flow it bleeds off excess gas.
I'll have to look into that one! Thanks!
SLR
I’ve tried a few.
SLR: very low profile, click detent adjustment, becomes difficult to adjust with use, but I haven’t had one seize up yet. Had a detent spring break on one, but excellent customer service took care of it. I hate how small of an Allen wrench is used for the adjustment screw. You will likely have to remove the handguard to adjust it over time, because you have to use the short end of the wrench to get enough torque.
Odin adjustable: 50/50 on this block. I have one this is still easy to adjust after use. I have another that has seized up beyond anything i’ve seen with any block. Customer service offered to replace it, I just haven’t taken them up in it yet. Click detents are great.
JP: this is the best so far. It’s the two piece design with click detent. I love that the adjustment is on the side instead of the front. I have a ton of rounds on it and it’s still adjustable.
I have a Superlative Arms block in the parts bin that I will try at some point.
SLR: very low profile, click detent adjustment, becomes difficult to adjust with use, but I haven’t had one seize up yet. Had a detent spring break on one, but excellent customer service took care of it. I hate how small of an Allen wrench is used for the adjustment screw. You will likely have to remove the handguard to adjust it over time, because you have to use the short end of the wrench to get enough torque.
Odin adjustable: 50/50 on this block. I have one this is still easy to adjust after use. I have another that has seized up beyond anything i’ve seen with any block. Customer service offered to replace it, I just haven’t taken them up in it yet. Click detents are great.
JP: this is the best so far. It’s the two piece design with click detent. I love that the adjustment is on the side instead of the front. I have a ton of rounds on it and it’s still adjustable.
I have a Superlative Arms block in the parts bin that I will try at some point.
If you are running a suppressor with a cover, be aware the bleed off gas block can destroy the cover if theybare close together.
I don't understand all the recommendations for a $100 gas block when the OP wants to set it once and leave it alone.
FWIW I've had gas blocks from $30 to $110 lock up solid on me, including two SLR's that sit in my junk parts drawer.
FWIW I've had gas blocks from $30 to $110 lock up solid on me, including two SLR's that sit in my junk parts drawer.
What do you recommend? this rifle isn't going to be shot as extensively or abused as my suppressed SBR. I wouldn't put an adjustable gas block on a "duty" style rifle like my other AR's. On a duty style rifle I switched out to a heavier buffer to keep the stock gas block and reliability that way and don't care too much if that type of rifle is slightly over-gassed. But this one, I want to get as much accuracy out of it as I can and tuning the gas system is where I'm at.
I've switched from SLR, Superlative, and JP to Wojtek. Simple set screw adjustment, doesn't lock as easily as the detent blocks and easier to get kroil into. Being $35 is also nice.
I've used 5-6 of the SLR's, all 7's with good performance so far. I don't care much for the bleed-off type.
MM
MM
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I like my superlative arms clamp on... i don’t utilize the bleed off feature though. Mine is on a 16” 5.56 that is suppressed.. i could be wrong but im only like 5-6 clicks from fully closed and it runs clean, dirty, and every lind of ammo i have tried in it.
I've settled on the SLR:
They do benefit from regular "exercise" to prevent them from seizing up, especially if you shoot 100% suppressed, like I do. After shooting, I run the gas block fully closed, out 15 clicks, and then back in to the normal my gas setting. Remember to fully close off the gas block adjustment screw prior to cleaning. More importantly, remember to open it back up, after!
Note that these do NOT work well under Geissele rails. The right lower corner of the gas tube channel inside Geissele forends will make contact with the right side of the SLR gas block when the barrel "noodles" as the gun is fired. I have not found an adjustable gas block that will work under a Geissele rail yet. I wish Geissele would get rid of those corners ...
They do benefit from regular "exercise" to prevent them from seizing up, especially if you shoot 100% suppressed, like I do. After shooting, I run the gas block fully closed, out 15 clicks, and then back in to the normal my gas setting. Remember to fully close off the gas block adjustment screw prior to cleaning. More importantly, remember to open it back up, after!
Note that these do NOT work well under Geissele rails. The right lower corner of the gas tube channel inside Geissele forends will make contact with the right side of the SLR gas block when the barrel "noodles" as the gun is fired. I have not found an adjustable gas block that will work under a Geissele rail yet. I wish Geissele would get rid of those corners ...
I am running a seekins on my 16". only about 500 rounds through it so not much to tell at this point. no issues thus far. easy to adjust through my rail but that was only to set it. haven't touched it since. just nice to know I can.
I've settled on the SLR:
They do benefit from regular "exercise" to prevent them from seizing up, especially if you shoot 100% suppressed, like I do. After shooting, I run the gas block fully closed, out 15 clicks, and then back in to the normal my gas setting. Remember to fully close off the gas block adjustment screw prior to cleaning. More importantly, remember to open it back up, after!
Note that these do NOT work well under Geissele rails. The right lower corner of the gas tube channel inside Geissele forends will make contact with the right side of the SLR gas block when the barrel "noodles" as the gun is fired. I have not found an adjustable gas block that will work under a Geissele rail yet. I wish Geissele would get rid of those corners ...
The SLR's come apart easily to clean; a big PLUS 10 on the Geiselle rails comments & fit as well...................learned the hard way, but the SLR rails are also top notch as well & I've used several of them.
MM
I am looking into getting a couple adjustable GBs for a few rifles I would like to tune further same as the OP.
So I've had multiple adjustable gas blocks that worked great as long as I didn't shoot the rifle much. Nowadays I've cut down on the number of rifles I have and have upped the amount of shooting I do on the rifles I own. I've found that parts that I thought were good to go on low round count rifles, were not so good after say 800-1K rds.
I've had major problems with carbon weld. Now I try to seek out parts that are gonna operate as long as possible and take the most punishment. It really sucks to spend $100+ on an adjustable GB to find after 1K rounds I shouldve just bought the $30 GB and chucked it like I did my now seized up $100 GB.
Tony, so you've had good luck with the Odin? I usually set my GB and leave it, but after so many rounds it's niceto be able to tune it as parts wear and break-in.
LRRPF52, that adjustable carrier looks like a pretty good idea. I've never ran one, but it seems much better than an adjustable key.
Wish someone made an adjustable 308 carrier, I would be tempted to try that out for sure. I may actually try out one of the Bootleg carriers after looking into it. How has yours held up so far? Is it easier to tune than a GB? Or I should say, is it finicky to tune?
Wish someone made an adjustable 308 carrier, I would be tempted to try that out for sure. I may actually try out one of the Bootleg carriers after looking into it. How has yours held up so far? Is it easier to tune than a GB? Or I should say, is it finicky to tune?
I'll probably never buy an AGB again since my experience with them is that they carbon-weld and are difficult to use after that, since there is not enough bearing force from a tiny Allen wrench to get the tiny set screw un-seized.
Whoever makes the first Adjustable Gas AR10 carrier is going to sell them like crack I think. The Bootleg design is the most user-friendly because you don't even need to remove it to adjust, and don't need any special tools, just a small flat head.
Bootleg isn't paying me, doesn't know I have it. I'm just reporting what I'm seeing so far, after decades of continuous experience on the AR15 (started actively shooting ARs in the late 1980s).
I've ran into the same situation with adjustable gas blocks. No matter what they eventually seize or strip on the ones I've tried.
I was considering either a Noveske SwitchBlock or a POF Dictator. The Noveske would be fine for 556. POF makes a Dictator jetted for 308 but the longest gas system they offer is mid length. Plus I've heard mixed reviews about POF products.
The adjustable carrier looks like a solid design I'm definitely gonna try on my 556 setup. If the AGBs out there just had a better adjustment control, like more of a knob vs. an Allen set screw or small lever. Something that gives you a little better leverage and is strong enough to last and not strip out. I always liked the Armalite SASS adjustable gas block set up, but unless you buy an SASS they cant be found.
If someone could adapt an FAL gas plug/ set up and jet it for DI instead of piston driven I would think would be a solid AGB design that's proven to work. Even if it were just loosely based off that design seems like a winner to me.
I was considering either a Noveske SwitchBlock or a POF Dictator. The Noveske would be fine for 556. POF makes a Dictator jetted for 308 but the longest gas system they offer is mid length. Plus I've heard mixed reviews about POF products.
The adjustable carrier looks like a solid design I'm definitely gonna try on my 556 setup. If the AGBs out there just had a better adjustment control, like more of a knob vs. an Allen set screw or small lever. Something that gives you a little better leverage and is strong enough to last and not strip out. I always liked the Armalite SASS adjustable gas block set up, but unless you buy an SASS they cant be found.
If someone could adapt an FAL gas plug/ set up and jet it for DI instead of piston driven I would think would be a solid AGB design that's proven to work. Even if it were just loosely based off that design seems like a winner to me.
Colt gas block uses a big ass knob. Savage rifles have large knobs. Innovative arms makes a receiver with adjustable gas knob. Micro MOA made a gas block with a plate that used different sized holes to adjust gas but I'm pretty sure they went under.
@ShooterwithNoName
I've not personally owned the Odin but buddies that I trust are happy with them. If a guy wants brand name and something with a lock screw to hold the adjustment I'd just go Odin, Seekins, etc.
I don't care about brand names or looking cool anymore so I just grab a $30 block from JoeBobOutfitters or similar, tune it to the new barrel it goes on then loctite it in place then toss it when the barrel is shot out.
I've not personally owned the Odin but buddies that I trust are happy with them. If a guy wants brand name and something with a lock screw to hold the adjustment I'd just go Odin, Seekins, etc.
I don't care about brand names or looking cool anymore so I just grab a $30 block from JoeBobOutfitters or similar, tune it to the new barrel it goes on then loctite it in place then toss it when the barrel is shot out.
I like slr. Whenever I clean the gun I put a little oil on the threads and work it a few times and haven't had one even try to sieze up on me.
I never got the draw of the superlative. I want enough gas to cycle the action and I want the rest pushing the bullet. Bleed off type gas systems are noticeably louder to me suppressed as well.
I never got the draw of the superlative. I want enough gas to cycle the action and I want the rest pushing the bullet. Bleed off type gas systems are noticeably louder to me suppressed as well.
I'm not sure I'd call it tunable. There's four positions. Two will function / lock the bolt back unsuppressed on my rifle.
What kind of issues?
I've got a Superlative Arms with 1500 rounds suppressed and zero issues; on the other hand, I've another SA that seized and broke the adjustment screw after 600 rounds.... ??? Go figure. They will fix though, just need to send it in.
YMMV but I don't play with my settings much . 99.9% suppressed and don't tinker after setting.
YMMV but I don't play with my settings much . 99.9% suppressed and don't tinker after setting.
For the longest time it was just too much pressure. Would pop primers and get ejector marks on the headstamp. tried to run it in a match while my buddy used my bolt gun. Ended up having to run with the gas off and charge every round, not fun and not efficient at all! I need to take it back out and work on it more, last year was moving and not much shooting, hoping 2019 is more promising.
If you are really going to shoot 98% of the time suppressed... this type of GB might be what you want.
I have seen SA bleed off and SLR's run hard with suppressors and have odd issues. mostly at the GB vent area.
While they are both excellent products, and very good at the task of limiting gas flow, I suspect the heat and high suppressor usage aspect will "over power" the designs.
Again, when used HARD.
A design with little moving parts and simple features may be a wiser choice.
Like the MicroMOA Ghonah... but I think they are out of business.
So, that leaves this... a simple insert GB... no real moving parts, just a insert restricting port size.
http://www.blackrivertactical.com/c...le-Gas-Block-750/p/102156493/category=6464009
I have seen SA bleed off and SLR's run hard with suppressors and have odd issues. mostly at the GB vent area.
While they are both excellent products, and very good at the task of limiting gas flow, I suspect the heat and high suppressor usage aspect will "over power" the designs.
Again, when used HARD.
A design with little moving parts and simple features may be a wiser choice.
Like the MicroMOA Ghonah... but I think they are out of business.
So, that leaves this... a simple insert GB... no real moving parts, just a insert restricting port size.
http://www.blackrivertactical.com/c...le-Gas-Block-750/p/102156493/category=6464009
Superlative Arms and SLR Rifleworks. As others have said, if you put a little lube in the screw every 500 rounds or so you should be fine. I've never had a problem with either.
And the advantage over a set and forget is you can get more aggressive with your tuning for each load and environmental condition if you want to.
And the advantage over a set and forget is you can get more aggressive with your tuning for each load and environmental condition if you want to.
I've settled on the SLR:
They do benefit from regular "exercise" to prevent them from seizing up, especially if you shoot 100% suppressed, like I do. After shooting, I run the gas block fully closed, out 15 clicks, and then back in to the normal my gas setting. Remember to fully close off the gas block adjustment screw prior to cleaning. More importantly, remember to open it back up, after!
Note that these do NOT work well under Geissele rails. The right lower corner of the gas tube channel inside Geissele forends will make contact with the right side of the SLR gas block when the barrel "noodles" as the gun is fired. I have not found an adjustable gas block that will work under a Geissele rail yet. I wish Geissele would get rid of those corners ...
Wes
Any Experience with the SLRs under a G Mk 16 or Mk 18 rail?
Set screw or clamp on?
Thanks
Nick
I stumbled on this seekins agb the other day and I think I'm going to try one the next time I need one.
https://www.seekinsprecision.com/select-adjustable-gas-block-876.html
https://www.seekinsprecision.com/select-adjustable-gas-block-876.html
Superlative arms is a great one, but it bleeds some gas out the front which could decrease velocity slightly. I have one, but haven't checked velocity. When I needed a second one, I bought one for $38 off ebay I think. (Not sure.) It is a no name one. It works fine.
I'd try and get one with a detent screw so it won't move under recoil.
I'd try and get one with a detent screw so it won't move under recoil.
If you have some basic skills with hand tools, you can do this with any gas block. For the low profile style pictured, all you need is a tap the same size as the lower set screws, one extra set screw, and various size drill bits. Everything you need is available from McMaster-Carr for under $30. I've done a handful like this with both low profile and A2 sight post gas blocks.
This is a good reliable method to tune a DI rifle. The only downside is the likely need to pull the gas block off a couple times as you sneak up on the right hole size, but once it's done, it'll stay set that way.
I've been talking about the Bootleg carrier here and other sites for a year or two now myself; they are a great system to switch between suppressed and unsuppressed, and is what I've been using on my 12.5" Grendel since early 2017.
I do think a really overgassed rifle still needs some sort of restriction tuning at the gas block as well though. With my rifles and suppressors, the Bootleg carrier has enough adjustment to go from open at position 1 to suppressed at position 4 and works well, but does not have the ability to also handle a severely overgassed system on top of that.
IMO the best setup is some type of "set and forget" gas adjustment (either the restriction style in the post above or something like the $60 Seekins gas block) for initial tuning unsuppressed, combined with a Bootleg adjustable carrier to switch for suppressed use. In that sort of use, I don't care if the gas block gets locked up with carbon, because it's not getting adjusted. Note that "locked up" is not the same as "blocked"; I've never had one become blocked.
The Bootleg carrier and adjustable gas block is not a cheap setup of course, but the best rarely is.
Nick - I've yet to encounter a Geissele Mk 16 or Mk 18, myself.
I am running SLR adjustable gas blocks on 5.56 and 6.5 Grendel. The Grendels also have the bootleg adjustable carriers for running suppressed.
The carbon "welding" is being way too over played. When I have needed to make an adjustment, I just put a couple of drops of kroil on the adjustment screw threads and set the gun muzzle up, so the kroil can do it's thing.
On the 223/5.56 I use factory ammo that I know is lower power and adjust to where the bolt locks on empty. Since my handloads are considerably stouter I have zero issues both suppressed and unsupressed, and did not find the value add for the bootleg adj carrier. So I set the SLR adj gas block and forget it for the most part. I have had to go back and change it for new barrels, and that is when I use kroil.
On the 6.5 Grendel they run way overgassed supressed, so same set up criteria as 223/5.56 for the SLR adj gas block unsupressed, and then adjust the bootleg for running suppressed.
Hope that info helps, as it allows for trouble free use both suppressed and unsupressed.
The carbon "welding" is being way too over played. When I have needed to make an adjustment, I just put a couple of drops of kroil on the adjustment screw threads and set the gun muzzle up, so the kroil can do it's thing.
On the 223/5.56 I use factory ammo that I know is lower power and adjust to where the bolt locks on empty. Since my handloads are considerably stouter I have zero issues both suppressed and unsupressed, and did not find the value add for the bootleg adj carrier. So I set the SLR adj gas block and forget it for the most part. I have had to go back and change it for new barrels, and that is when I use kroil.
On the 6.5 Grendel they run way overgassed supressed, so same set up criteria as 223/5.56 for the SLR adj gas block unsupressed, and then adjust the bootleg for running suppressed.
Hope that info helps, as it allows for trouble free use both suppressed and unsupressed.
I'm
whenever I build my 18" Grendel that's why I think I'm going to try the seekin's select agb. Screw adjustment to fine tune the minimum opening with can on and then you install the lever on it so that you can bump it open without tools when the can is removed. Seems like a good idea but I haven't seen any reports on them.
whenever I build my 18" Grendel that's why I think I'm going to try the seekin's select agb. Screw adjustment to fine tune the minimum opening with can on and then you install the lever on it so that you can bump it open without tools when the can is removed. Seems like a good idea but I haven't seen any reports on them.
