Thread: DIY adjustable gas block

After I fitted a DPT suppressor to my CMMG Ar15 I was surprised how much gas blowback I was getting, both out the bolt and rear of the charging handle. I had noticeably more recoil and the sound reduction was decreases by the obvious noise coming out of the upper. Due to a lack of adjustable gas blocks for what I would call a reasonable price I decided to make my own, if I wrecked mine I'd just replace it with a new adjustable one.

$7 later from the Engineering Supplies shop I had a 4mm grub screw, 4mm tap and appropriate size drill. Clamped it into my drill press vice and very carefully drilled until it had just cleared the other side of the gas transfer port, carefully tapped the thread and screwed the grub screw in with a bit of thread tape.

Had a play over the last few weeks to get it set as I started with it all the way out and steadily screwed it in, still haven't had it fail to cycle and it's almost bottomed out so I'll locktite it where it is.
Other than the $5 foam from Para Rubber glued onto the terribly uncomfortable Spears stock it's the best mod I've done

nice

pics of the foam thing to make stock better?

I would but I've just pulled it off, I cut it a bit too long and it interfered with my charging handle, never thought of that. Cutting a neater one to be more permanent, original was just held with 6 small dots of super glue

If it helps the correct way to adjust is to load a single round in the mag. close gas blockfully and after firing the bolt should lock back. If not open it a little and try again until it does

Originally Posted by mikee

If it helps the correct way to adjust is to load a single round in the mag. close gas blockfully and after firing the bolt should lock back. If not open it a little and try again until it does

Nice, I usually just single shoot at the range anyway and load through the ejection port, saves me cooking my suppressor and it's the only way I can load my long range rounds with 80gr+ projectiles into my modified single shot magazine

Not meaning to be rude, but does that not defeat the purpose of owning a semi ?
Obviously reason enough to make it worthwhile for you, well done on your engineering on the gas block.

na mate what he done still allows it to cycle it just calms the over gassing caused by the suppressor bieng added

Id highly reccomend the 'poor mans gas buster mod' which is basically just a bit of high temp silicone applyed neatly to the top of the charging handle to stop gas going in your eye
made a huge difference on mine

top marks on the home made adjustable gas block, thats good thinking

Originally Posted by Moutere

Not meaning to be rude, but does that not defeat the purpose of owning a semi ?
Obviously reason enough to make it worthwhile for you, well done on your engineering on the gas block.

Don't know whether you're referring to the gas block or the shooting a round at a time at the range defeating the point of a semi. Can adjust the grub screw through my hand guard with no modification so if it ever fails to cycle on a light load it can be wound out.

Don't worry though I still do 30 round mag dumps shooting beer cans, which is the main reason for owning an a rattle gun, single loading is mainly to be able to shoot steel at 400m consistently to show up my mates expensive Remington 700 5r

Yeah Bill I copied someones idea and did the 'poor mans gas buster too' but no longer need it so it's nice to remove it cos it was a bit rangi

Yeah, sorry not so clear above,
Why the single shot AR was the query there, enjoy your rattlely mag dumps in between the long range stuff.
Figured your reasoning would something be along those lines.

When you look at it, you generally have a 1:7 twist on AR's these days, so it makes sense to single load a 75gr A max when the situation warrants it. Can slap a mag full of cheap 55gr in for closer in things afterwards.

Originally Posted by specweapon

...$5 foam from Para Rubber glued onto the terribly uncomfortable Spears stock...
Attachment 26226Attachment 26227

@specweapon, here's what I did to mine, so I could fit the foam from an ACE or Servo stock...