AR15 Gas Block Install - Need to Drill Taper for Pins

smgcon

smgcon

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Does anyone have a gunsmith who can install a new gas block on an AR15 barrel for me? It has never been drilled for a gas block, and I wish to use taper pins, which I have.

I have a new undrilled barrel coming, as well as a new undrilled gas block. I just need someone who has the correct size drill bits, as well as the taper pin reamer.

Thanks.
 
As a matter of interest, some of the match barrel makers for AR's in the states DO NOT use taper pins. The real trick is to drill through the bottom of the gas block and tap it for 6/32 or 8/32 set screws. When you put the block on the barrel, use green lock tite and use the screws only to allow the lock tite to set. The thought being that driving these taper pins into the block and barrel actually causes the barrel to bulge into the bore where the pins are located. I've done an experiment where I took a pined barrel, removed the pins and used this method and found a slight increase in accuracy, say 5% or so. It is also way easier to set up a gas block using this method and drilling a tapered hole without the proper fixture is a pain in the behind to the 10th degree. If your gas block has a front sight attached, it also allows you to correct for slight sight alignment issues before you lock tite the block. You can move the front sight slightly left or right on the barrel and still locate the gas hole and this allows you to set your rear sight dead centre. Al of this work can be done on a good drill press or a drill mill in a fraction of the time for the set up and drilling of those taper pins!!

Scott
 
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If I understand you correctly, you're saying to apply the green loctite to the bearing surface between the gas block and the barrel, not on the screw threads?
 
Yes NOT the set screws. Green lock tite is a hydrolic lock tite, you can hold bearings together with it when applied correctly. I've done this on several AR's, even leaving out the lock tite and the rifles have shot very well. Once you snug down on those screws, as the tolerences are pretty tight on the block and the barrel anyway, the block holds very securely. If you are free floating the barrel, using a houge tube for example, even better as your sling will now be mounted off the barrel via the front sight sling swivel so you produce a very accurate rifle indeed.

What are you building exackly?
Scott
 
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m39a2 said:
As a matter of interest, some of the match barrel makers for AR's in the states DO NOT use taper pins. The real trick is to drill through the bottom of the gas block and tap it for 6/32 or 8/32 set screws. When you put the block on the barrel, use green lock tite and use the screws only to allow the lock tite to set. The thought being that driving these taper pins into the block and barrel actually causes the barrel to bulge into the bore where the pins are located. I've done an experiment where I took a pined barrel, removed the pins and used this method and found a slight increase in accuracy, say 5% or so. It is also way easier to set up a gas block using this method and drilling a tapered hole without the proper fixture is a pain in the behind to the 10th degree. If your gas block has a front sight attached, it also allows you to correct for slight sight alignment issues before you lock tite the block. You can move the front sight slightly left or right on the barrel and still locate the gas hole and this allows you to set your rear sight dead centre. Al of this work can be done on a good drill press or a drill mill in a fraction of the time for the set up and drilling of those taper pins!!

Scott
Click to expand...

Scott, good post. This is a great idea on a precision/game gun but in no way do we recommend this be done on a professional use gun or one that will see any type of course use.
 
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Correct, this is a set up for an accuracy piece not one that will be used for real!
I should have been a little clearer on what I was talking about. Thanks for pointing that out.
Scott
Dycor Special Services
 
yeah green locktight is special stuff..abit pricey though. I have a huge tube of here. Interesting that its used for a seal application on guns. I use it occasionaly for tranmission/hub seals.
 
All,

Loctite color usually means very little.

Go by the #.

For example, there is a green loctite threadlocker that WILL NOT work in this application, i think it is #212, for screws smaller than 10-32

There are 5 different common red locktites... #262 (3/4 bolts permanent) #263 (3/4 bolts permanent, wicking) #272 (1" bolts permanent) # 277 (1 1/2" bolts permanent)#620 Sleeve retainer (permanent)

Please go by the # of the loctite.

The green loctite that you want is "sleeve retainer", and unsure of the #.

MikeH
 
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