Does anyone know of an inexpensive adjustable .625 gas block?  I don't have the funds to spend $100, looking to spend more like $50 or less.  I have looked around and most of the less expensive ones are all .750.

I am putting it on a Faxon 16" Pencil 5.56 barrel and have a light weight BCG.  Might just buy a Faxon block and make a DIY adjustable.

I was also thinking about just crimping the gas tube. I know this would make it so I couldn't adjust it up and down but if I could find a good medium between cycling for 55gr and accuracy for 77gr that would be fine. Just wondering if there would be any other downside other than not being able to open it up without replacing the tube.

On my lightweight build I just run a standard gas block, have the AIM lightweight bcg and run a sprinco red spring with a standard 3oz buffer. It runs 100% and ejects at 3 oclock. I ran a non adjustable gas block only because it came pinned with my barrel (BA Hanson .625) Most adjustable blocks will run 75 and above for a .625.

Dude, just wait one more pay day. It's gonna be ok, I promise. Master of Arms is calling your name.

Ask yourself....what is the right way to do want you want to do.
Because crimping a tube that wasn't designed to be crimped isn't the right way.
And I seriously don't see you being capable of  performing the adjustment mod on a regular gas block.

So what does that leave you....save your money, and find the correct part for the best price. Don't do some bubba gunsmithing crap you'll regret doing, and then have to fix all over again.



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I ended up getting a superlative arm bleed off AGB. One of my objectives is to make the rifle light with minimal recoil and blast so my wife and a female friend who is new to shooting can handle this gun well. I think that gb fits the bill.

And as for crimping the gas tube, who says it isn't designed to be crimped. I have never seen any documentation on any manufacturers web site saying "do not crimp". Sure, it wouldn't be mil-spec, but lots of commercial parts aren't. It's just metal fabrication.  If you have the mindset of an engineer everything is possible, you just have to have to have the right tools. I'm not talking about just smashing it with a pair of pliers. There would need to be some math involved and the right tool used to make the diameter of a certain length of the tube smaller which would stretch the tube longer requiring it to be cut back to proper length. You might ask about overheating because there is less metal and possibly more pressure causing the tube to overheat, but my guess is only full auto mag dumps would cause that.  But trust me, it could be done in a proper, effective way.  There is a gas tube that has an adjustable valve so I believe gas regulation at the tube is a viable option.  And until someone tries it you can't prove it wouldn't work.

If I had more range time I would go do it just to test it out.  Bubba gun smithing is a great way to learn, how do you think new gun ideas get tested? You put something together, if it doesn't work you modify it. And gas tubes are cheap. I have extra rifle length tubes just sitting around.

No matter how well it's done there are issues with crimping a tube. A choke point for carbon to build up that is difficult to clean isn't a good thing. The adjustment is also "1 way" and permanent. What if you want to use a different ammo or you crimped it 1% to much for 100% reliability? Now you're buying a second tube etc.

You made the right decision. An engineered adjustable gas block or gas key is the way to do this.

Glad you chose the proper way to address the issue

 Engineering "mindset" .....

 It is the engineering "mindset" that gave us adjustable blocks, adjustable gas keys, and piston drives.  Engineers use math, formulas, and computer simulations to come to a solution.

 Engineering mindset doesn't mean smashing something to see if it works. That is ignorant, and bubba.
And then to make a claim that "the tubes don't have a label or warning tag saying  not to smash.....are you serious ??

  I'll give you a hint about volume and size......If you decrease the size of a tube, and the volume of gas remains the same, you increase velocity.
And if you reduce the size of the tube too much, making the walls too  thin.....the gas will seek the point of least resistance....kaboom.
So how would your wife or friend look with a face full of shrapnel ??

You are not an engineer, you do not possess an "engineering mindset",  and you are not a fabricator.
I would also guess you have very little in the way of having tools and equipment.

So.....smashing gun parts is bad, and don't expose people to dangerous things you think are good ideas.


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I've made my own AGB's and they work fine. Just drill, tap and add a screw with lock nut.

Also seen gas tubes with a screw adjustment added inline to restrict the gas flow. Found it simpler to just modify a regular GB than go that route.

I still believe it's a viable option and you can say what ever want, it would work. That would not be any more "bubba" than drilling your own gas block to make it adjustable. I don't shoot high volume and am sure the tube would be thick enough to hold. And if the tube did fall, one could always reinforce the area of the tube that was thinned.

Maybe I'm just more skilled and open minded than you.

And I don't know why you said I would be smashing my gun. <edited> COC Violation (#6) keep it civil. This is a tech forum. PursuitSS

I would think if you are skilled enough to reinforce a gas tube if needed. Then why don't you add material to it, drill and tap a hole, and install a set screw. That would then make you gas tube adjustable.

Battle Tested Equipment.  $35.   Sorry I was late to the party.

Just put one on my Faxon pencil barrel.

Attached File

More skilled than me.....ROFLMAO !!!

I have a shop in my garage.....
I have a mill, a lathe, TIG welder, MIG welder, horizontal and vertical bandsaws, various belts and disc sanders, etc, etc.
I mill my own 80%er's, cut/thread/pin my own barrels, made my own brakes and comps, drilled/tapped gas blocks, etc, etc.

I also build Jeeps...so I've rebuilt manual transmissions, transfer cases, diffs, and fabricated dozens of cages...all with the help of a full-hydro tubing bender I built that uses JD2 die sets.
I do electrical, paint, and I can fabricate hard and soft hydraulic lines, fuel lines, braided lines, etc.
FWIW...my Jeep was recently featured online, and should go to print sometime this year in JP magazine.




Like I said before....you have no fab skills, and you have no tools to perform fab work.
The fact that you come on here to ask what to do tells me everything.
Your a talker....not a do-er.
Otherwise, you wouldn't have had posted anything.

And you may want to read what I wrote  little more closely....I said smashing gun parts. Which is exactly what crimping is.  


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Being a 'heep' driver isn't helping your cause...Barbi/Ken had one for a reason. Full-size chevy or death.

This thread has ran its course.