"Combat" AR15 build gas block question

[DDadams]

What would you fine folks recommend for a "shtf" AR15?

Now that my lightweight build is done and I scored a wonderful LMT Mars-L lower I want to have something totally opposite with this one. Something that can go to hell and back.

Some people on other sites have said pinned gas blocks are the only thing they'd truly trust. Is that a belief you hold?

And adjustable? Or not?

I do have a suppressor in jail for this build already. An Otter Creek Polonium.

I was going to use a Faxon barrel because they come overgassed from the factory at .080 mid length typically and if I go adjustable gas I was thinking about using JP's adjustable front sight block or the superlative arms block for the bleed off.


Or for this type of build would you go piston? I really want to get a BRN-180 upper just so I can have a folding stock without using a law folding adapter because of some people having issues with them.


Any opinions and insight is greatly appreciated.

 

[jason867]

My 2 opinions, only worth what you paid for them, i have no direct experience, only read a lot:

1. If you get an overgassed barrel, then definitely get an adjustable gas block, because an overgassed gun can have problems cycling. Attaching a can will exacerbate this.

2. If you're wanting to suppress this gun, then don't get a gas bleed-off style gas block. That gas bleed off is noise, which will be worse with the extra backpressure from a can attached. This partly why the ak rifle doesn't supress very well, it's gas system is vented.

 

[BR8818]

If your wanting "bomb proof" then non adjustable is the answer w/ a properly gassed barrel its less parts to break. Since you mentioned wanting an overly gassed barrel, I'm assuming your thinking about an AGB to have an adverse, regular, and suppressed setting like a piston gun. If thats the case look at Riflespeed. I'm using one on my .308 AR its pretty sweet so far (about 600rnds) the ability to adjust the gas on the fly is great especially with a .308.

 

[NyleRN]

What would you fine folks recommend for a "shtf" AR15?

Now that my lightweight build is done and I scored a wonderful LMT Mars-L lower I want to have something totally opposite with this one. Something that can go to hell and back.

Some people on other sites have said pinned gas blocks are the only thing they'd truly trust. Is that a belief you hold?

And adjustable? Or not?

I do have a suppressor in jail for this build already. An Otter Creek Polonium.

I was going to use a Faxon barrel because they come overgassed from the factory at .080 mid length typically and if I go adjustable gas I was thinking about using JP's adjustable front sight block or the superlative arms block for the bleed off.


Or for this type of build would you go piston? I really want to get a BRN-180 upper just so I can have a folding stock without using a law folding adapter because of some people having issues with them.


Any opinions and insight is greatly appreciated.

Wait till Black Friday and grab a Giessele complete duty upper. (Not the super duty upper) They're the best bang for the buck. They usually go on sale for about $650-700.

 

[ditcherman]

I have a JP adjustable block on one, and it’s nice but will say if I get it shooting “just right”, perfectly soft but still reliable and change ammo then it can become not reliable. So I keep it one up from just right. Which is fine. I have not seen a huge benefit to me having one, but wanted the experience.
With a can I think it’d be nice.

Not sure why pinned matters if barrel is detented, but I don’t know what I don’t know so….

Do all piston guns have an adjustable gas block of some sort? That might be the way to go for reliability, but it depends on how you define hell and back. Are you alone, so parts interchangeability doesn’t matter? You’ll find a lot more gas guns on the way back from hell if you were with others.

 

[Hop]

I've had dimpled barrel bolt on gas blocks come lose. Taper pinned is the way to go if you truly want a "GTW" rifle.

I have an 18" Faxon with a Warblock & have never had one lick of trouble with it. The barrel still shoots sub MOA (unsupported, sling only) with off the shelf ammo.

WarBlock Barrel Builder - War Machine LLC

All of us want something different for a specific build we have in mind. The Barrel builder Web app allows you to pick and choose what components you want to include on your built-to-order barrel assembly and none of the ones you don’t. This can save you time, headache, and money when forced to...

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[Goodcat]

Pinned if you can, at-least dimpled. I use after market converted barrels on all my LMT builds and use FCD gas blocks. I would never use an adjustable gas block on any serious build. Too much that can, and has, gone wrong. Tune with springs and buffers. I highly recommend the Vltor A5 system also.

 

[DDadams]

Pinned if you can, at-least dimpled. I use after market converted barrels on all my LMT builds and use FCD gas blocks. I would never use an adjustable gas block on any serious build. Too much that can, and has, gone wrong. Tune with springs and buffers. I highly recommend the Vltor A5 system also.

I was going to use the vltor A5.

One thing I can't find definitive answers for is the actual receiver extension from Vltor - is the actual tube proprietary or can I use a V Seven made A5 buffer tube with the vltor buffer/sprinco spring?

Edit: I take it you run suppressors on those builds as well, right? Without the adjustable blocks?

Maybe I should wait for the Criterion barrels to be back in stock rather Faxon to get a smaller gas port then..


Thanks for all the good advice so far guys. I really appreciate it.

 

[Goodcat]

I was going to use the vltor A5.

One thing I can't find definitive answers for is the actual receiver extension from Vltor - is the actual tube proprietary or can I use a V Seven made A5 buffer tube with the vltor buffer/sprinco spring?

Edit: I take it you run suppressors on those builds as well, right? Without the adjustable blocks?

Maybe I should wait for the Criterion barrels to be back in stock rather Faxon to get a smaller gas port then..


Thanks for all the good advice so far guys. I really appreciate it.

Yes, I run them unsuppressed and suppressed without adjustible gas blocks. Criterion core for my 11.5. A5 system was made by Vltor, but is simply an intermediate length tube, special buffer, and a rifle spring. So Vltor, V-Seven, FCD, etc A5 tubes all work. V-Seven is a fine choice, but I prefer FCD. I’d always use Sprinco green rifle spring. Start with A5H2, and see ejection patterns. I normally end up at an A5H2 anyways.

 

[DDadams]

Yes, I run them unsuppressed and suppressed without adjustible gas blocks. Criterion core for my 11.5. A5 system was made by Vltor, but is simply an intermediate length tube, special buffer, and a rifle spring. So Vltor, V-Seven, FCD, etc A5 tubes all work. V-Seven is a fine choice, but I prefer FCD. I’d always use Sprinco green rifle spring. Start with A5H2, and see ejection patterns. I normally end up at an A5H2 anyways.

Sounds about what I had thought. I'm a huge fan of V Sevens products and FCD although I've only used a very few amounts of FCD stuff until recently. The only reason I was going to use V Sevens A5 is to save a miniscule amount of weight as I know this build will be somewhat heavy compared to what I've been shooting.

Up until the beginning of this year I just bought cheap ARs like PSA and Anderson. I got a bit worried I would never be able to buy or build my "dream" rifles and started to put some money into them finally.

I was going to do a Mars-L SBR but I got this lower in a private sales so I'd rather just keep it to myself and SBR something already "on the books".

So I guess for now the build looks like this roughly, (any adjustment advice is appreciated here too, from anyone, for any part)

Aero enhanced m4e1 upper
Aero Atlas S-one enhanced
Lmt mars lower
Chrome Young mfg BCG with HMB bolt
Criterion core 13.9 (nitride from ADM not chrome)
FCD gas block
V Seven EE inconel gas tube
Solgw NOX p/w muzzle device
Geissele combat flat trigger
Vltor A5 buffer
Fab defense gl core stock
Fcd/lmt lower parts

 

[Squid556]

I’d say your lightweight rifle is already the go to option. Lots more carrying happen than shooting in a real life shtf.

A standard m4 carbine is capable of easily withstanding a whole combat load of ammo about as fast as you can keep it fed. Basically I don’t think you’ll ever need to build a rifle stronger than that because you’ll not be able to carry enough ammo to feed it.

But for arguments sake if you’re wanting something different and designed to put the lead out I’d buy and upper that’s close to the M27 IAR. Basically a socom or Hbar 16 inch barrel, piston driven. I’d recommend buying a complete upper from a mfgr. You can actually buy the MR556 upper from HK if you can stomach the price. But there are many other companies offering what you’re looking for.

I had a Stag model 8 about ten years ago. Piston driven 16 inch. Thought I needed it. Turns out I like the original stoner gas system more. Lighter weight, simpler.

Far as gas blocks go, pinned or clamp style are the strongest. Set screw is the least desirable for what you’re wanting.

Wouldn’t recommend a brn 180 for your SHTF rifle. Nothing wrong with them as far as I know but a smart SHTF rifle will be parts compatible with other peoples rifles. BRN is not.

 

[ltromann]

What would you fine folks recommend for a "shtf" AR15?

Now that my lightweight build is done and I scored a wonderful LMT Mars-L lower I want to have something totally opposite with this one. Something that can go to hell and back.

Some people on other sites have said pinned gas blocks are the only thing they'd truly trust. Is that a belief you hold?

And adjustable? Or not?

I do have a suppressor in jail for this build already. An Otter Creek Polonium.

I was going to use a Faxon barrel because they come overgassed from the factory at .080 mid length typically and if I go adjustable gas I was thinking about using JP's adjustable front sight block or the superlative arms block for the bleed off.


Or for this type of build would you go piston? I really want to get a BRN-180 upper just so I can have a folding stock without using a law folding adapter because of some people having issues with them.


Any opinions and insight is greatly appreciated.

So, you're off to a good start with the LMT MARS-L, thought I prefer the LWRC IC Lower, the mars is a great option.

Not sure on how long of a barrel your wanting. But pick up a Centurion Barrel HF/CL, they're some of the best barrels out there and pair it with a Centurion Tabbed Gas block and a gas tube from Trajectory Arms.
For your upper look at the Vltor MUR. They're tough, forged and built well. Centurion is a really solid option for handguards as well, but one of my favorites is the BCM MCMR.
For your recoil system, go with the vltor A5 System. Need an a5 length tube, a5 buffer and a rifle spring, preferably the springco green spring.
For your trigger, id recommend a Geissele. They make the best AR triggers out there, period.if you don't want to spend G money, schmid makes a great 2 stage Trigger, same as the centurion AST and the FCD 2 stage and many more.
Don't get a cassette style trigger and don't get anti walk/rotation pins. The Pins in an AR are designed to rotate as you shoot. And the anti walk pins are a temporary solution for an out of spec lower or fire control group.
FCD makes some great and durable parts as well to give you some more to look at.
My favorite charging handle is the BCM 4x4. Tougher and manages gas better than the radian and Geissele handles.
For your BCG, there's several options, but a good phosphate finish and c158 will do you well. Like SOLGW, Centurion, MA, BRT, BCM, FCD, Sionics. Theyll be extremedy reliable and durable and all come with good warranties. Especially the solgw one.

Avoid strike, and a lot of the real cheap stuff. Go for quality.

This will set you up with a bomb proof gun. It'll be extremely reliable and should run any ammo you put into it. Feel free to hit me up if you need specifics or more help.

 

[DDadams]

Anyone have a recommendation on a front sight gas block? Just get the standard one from BCM? The 'F' marked ones?

I know JP makes an adjustable one but it appears I'm not going adjustable on this gas block.

Was just going to go with a FCD block but I really want a fixed sight gas block for the look. It's all about the look after all, function comes second right..?

 

[ltromann]

Anyone have a recommendation on a front sight gas block? Just get the standard one from BCM? The 'F' marked ones?

I know JP makes an adjustable one but it appears I'm not going adjustable on this gas block.

Was just going to go with a FCD block but I really want a fixed sight gas block for the look. It's all about the look after all, function comes second right..?

Check out the A.R.M.S. #41 sight/block.
Some others that are pretty cool, PRI flip up, Vltor sight tower, YHM flip up, Samson quick flip up

For some standard front sight gas blocks, BCM, JP, Fulton Armory, CMMG, Daniel Defense,

Avoid any gas blocks that are made from Aluminum.

I'm sure I missed a few, but there's a good spread of different options. If you've got a Centurion Barrel, a centurion tabbed gas block is a good option for a low profile. Nothing wrong with the FCD one. It's very solid.

 

[Bigtanker]

I can see it starting.

Now off to bed.

 

[DDadams]

Check out the A.R.M.S. #41 sight/block.
Some others that are pretty cool, PRI flip up, Vltor sight tower, YHM flip up, Samson quick flip up

For some standard front sight gas blocks, BCM, JP, Fulton Armory, CMMG, Daniel Defense,

Avoid any gas blocks that are made from Aluminum.

I'm sure I missed a few, but there's a good spread of different options. If you've got a Centurion Barrel, a centurion tabbed gas block is a good option for a low profile. Nothing wrong with the FCD one. It's very solid.

I appreciate that. That A.R.M.S. one is really cool! Wish I knew about that sooner.

But I'm just talking about a fixed post for this now so most of those are out of the question.

I'm going to have my handguard cut for the post to stick out of the rail.

 

[ROLEXrifleman]

At this point all you’re describing is a standard A2 front sight on a whatever length barrel you want. Either 10.5, 11.5, 14.5, 16, or 20 inch, or whatever the hell else barrel length is made now a days, just pick the manufacture that fits your budget with the A2 installed from them. Gas port will be fine and the sight will be pinned. Not much more “bomb” proof than that. It’s worked well for the military for decades.

And as said above a few times. NO to adjustable gas

 

[ltromann]

I appreciate that. That A.R.M.S. one is really cool! Wish I knew about that sooner.

But I'm just talking about a fixed post for this now so most of those are out of the question.

I'm going to have my handguard cut for the post to stick out of the rail.

Before you Chop, look into Centurion handguard. They have options where the handguard is already cut for it.

 

[Elcardo]

Before you Chop, look into Centurion handguard. They have options where the handguard is already cut for it.

C4 pic rail on an 11.5 fsgb is definitely my next build .....it moves every time I see that setup

 

[DadSmith]

Check out the A.R.M.S. #41 sight/block.
Some others that are pretty cool, PRI flip up, Vltor sight tower, YHM flip up, Samson quick flip up

For some standard front sight gas blocks, BCM, JP, Fulton Armory, CMMG, Daniel Defense,

Avoid any gas blocks that are made from Aluminum.

I'm sure I missed a few, but there's a good spread of different options. If you've got a Centurion Barrel, a centurion tabbed gas block is a good option for a low profile. Nothing wrong with the FCD one. It's very solid.

I've used the YHM flip up front sight. It's a well made part. However, that was close to 20 years ago maybe less. I'm not sure if YHM is still a quality manufacturer anymore.