Adjustable Gas Block??

N

newmexkid

New member
OK. Back at it again with my first ever AR 15 transformation. Got a DPMS "Oracle" from Cabela's and will be putting a longer, heavier barrel on it. The barrel will be either a .936 20"or 24" Not knowing what I'm doing, I ordered a JP Adjustable Gas Block. Got to looking at the gas block last night. Looks like I have to tread a small hole in the gas tube, chase treads with a tap die, etc. I am totally lost on the whole procedure to install this thing. So, do I need an adjustable gas block? Is there a different block I can purchase that is not so "hard" to install? HELP
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You should not have to drill, tap or modify anything. The gas tube just slides in and the a small supplied roll pin gets driven into the gas block and though the hole in the gas tube.
Just make sure you line up the hole in the tube with the hole in the gas block.
 
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They are just like a regular block in gas tube mounting. It is IMPERATIVE that you use some RTV gasket material on the adjustment screw as it WILL fall out. JP tells you to do this BTW They gave me some good natured ribbing when I called up for s new one. I do this on JP, BTE, Joe Bob and Double Stsr blocks. The new ones from Tactical Ammunition do not need it. Not as braggable as the click adjustable ones but a heck of a better deal on my pocket book plus they don't carbon up solid.

Greg
 
The gas block is a JPGS-8.

From their install sheet;Run a 6-32 H1 or H2 bottoming tap into the gas adjustment hole from the side to score the gas tube. A normal tap may be used, but the tip may have to be ground off. The purpose here is to cut threads into the bottom of the gas tube to allow the adjustment screw to position tightly against the gas tube. This tapping can be performed even though the detent mechanism is in place.

This is one of the things that's got me messed up and looking for a more simple gas block
 
I guess that's why I run a non adjustable. Fear of a failure to cycle or feed. All my shooting is at coyotes and jams aren't good in total darkness. I'm too tight to buy a click type and I'm guessing those require a higher dollar handguard with a bigger ID which I did get for my 6x6.8 that is being wittled out.
 
So the gas control screw comes in from the top side of the GB and has to screw directly into the gastube to block gas hence the tube needing tapped??????
 
I've modified quite a few of my own non adjustables with set screws to make them adjustable so I have a pretty good idea the issue here. On their .750 gas blocks you don't have this issue. But the .936 blocks put the gas tube very close to the barrel, most all are this way. They just can't go much higher. Therefore, there isn't enough room between the top of the barrel and bottom of the gas tube for a set screw unless it intrudes into one or the other. So they end up having the set screw threading into the cut out on the bottom of the gas tube. When I drill and tap a regular gas block for an adjustment set screw I always install the gas tube first, then the tap cuts into the tube just like they are instructing.

All you really need is to go to Ace and get a 6-32 tap, should be about 5 bucks, and grind the tapered part off the end so it's cutting threads all the way to the end. Or get a bottoming tap if you can find one, and install the gas tube and run the tap in carefully. I have broken those tiny taps before, so go slow and easy.

I am surprised they don't sell them with gas tubes installed and rtg.
 
Originally Posted By: varminter .223Troy .936 nonadjustable is an low pro as they get. I have one on my 6.5x6.8 bull barrel AR

Thank you
 
All you need to do is install your gas tube in the gas block as you would with any other gas block, then run a bottoming tap through the adjustment hole so it can just catch the small amount of material that doesn't line up perfectly on the gas tube, if you don't then the adjustment screw will catch the edge of the hole on the gas tube and won't be able to close all the gas off for proper adjustment. No need to buy a different block
 
Thanks guys. A special thanks to kooman for the PM that finally made me understand what he was trying to tell me. Gas block is now all set up. Will install tomorrow. Don't have time today...Daytona 500 race is getting ready to blast off.
 


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