OK. Tonight I installed my first barrel, gas tube and non adjustable gas block. I feel pretty good that I installed everything properly. Used moly grease to install the barrel, tightened and loosened up the barrel 3 times and then used a torque wrench at 30 ft. lbs. and tightened up until the gas tube moved freely. Setting the gas block was straightforward . However, I have something nagging at me. How do I know if the hole in the gas block is lined up with the hole in the barrel?
Gas Block Position
- Thread starter newmexkid
- Start date
thegoodlife
New member
I've put together many uppers, the method I use:
I put a expandable foam ear plug in the chamber to seal it off, and without the flash hider on I blow down the barrel while adjusting the gas block. You will hear it when the gas block is getting the most air through it.
I put a expandable foam ear plug in the chamber to seal it off, and without the flash hider on I blow down the barrel while adjusting the gas block. You will hear it when the gas block is getting the most air through it.
Originally Posted By: thegoodlifeI've put together many uppers, the method I use:
I put a expandable foam ear plug in the chamber to seal it off, and without the flash hider on I blow down the barrel while adjusting the gas block. You will hear it when the gas block is getting the most air through it.
I was trying to remember the method you described but, couldn't. I knew it involved air but, not the process. I think that should work. Thanks
I put a expandable foam ear plug in the chamber to seal it off, and without the flash hider on I blow down the barrel while adjusting the gas block. You will hear it when the gas block is getting the most air through it.
I was trying to remember the method you described but, couldn't. I knew it involved air but, not the process. I think that should work. Thanks
reloader326
Member
If you do find that the holes don't line up, what are your options?
Grind or shim the gas block, I would assume.
Grind or shim the gas block, I would assume.
thegoodlife
New member
Originally Posted By: reloader326If you do find that the holes don't line up, what are your options?
Grind or shim the gas block, I would assume.
I've never heard of this option. If this ever was the case I would just buy a new gas block
Grind or shim the gas block, I would assume.
I've never heard of this option. If this ever was the case I would just buy a new gas block
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Many barrels have a dimple on the bottom. You merely line the back gas block hole screw with those and tighten it down as the last screw hole is directly below the port.
Without a dimple measure from the shoulder on the barrel to the center of the gas port. Now measure the center of the gas port location from the back of the gas block. Subtract the second from the first and that will be your off set from the shoulder for the rear of the gas block. Tighten it down. MOST blocks require about 0.030 space off the shoulder. Some do not and the brands change all the time.
Greg
Without a dimple measure from the shoulder on the barrel to the center of the gas port. Now measure the center of the gas port location from the back of the gas block. Subtract the second from the first and that will be your off set from the shoulder for the rear of the gas block. Tighten it down. MOST blocks require about 0.030 space off the shoulder. Some do not and the brands change all the time.
Greg
The gas blocks are made with a chamfer to allow for some misalignment. I have personally seen them off by quite a bit and they still work.
I line up the gas tube with the hole in the upper and look down over the gas port as I slide the block in place. Works just fine. it does not have to be that exact.
I line up the gas tube with the hole in the upper and look down over the gas port as I slide the block in place. Works just fine. it does not have to be that exact.
You can usually look down the long axis of the rifle from the top and can see if it is straight. I assume you got the one that requires an allen wrench to tighten up the two screws on the bottom. Just take the allen wrench to the range. When you shoot, if the bolt doesn't lock back you can adjust it. Not really something you should be worried about, it's an easy fix.
I usually mark center of the gas port on the barrel just behind the shoulder with a pencil then do the same thing on the back of the gas block. Line up the 2 marks when you slide it on. I put the gas block all the way against the shoulder on the barrel. Have not had a problem with any I have done like that.
Well, right or wrong this is what I did. Took some measurements on the block and the hole in the barrel. You know...x-y plus pi. Oh yeah! Made some pencil marks on the barrel. Lined everything up and cinched it up, (clamp style block). Looked nice and straight. Next I sprayed a bunch of barrel cleaner through the muzzle. Then I put the air hose to it and blew the cleaner out. At that point some solvent came out through the roll pin hole on both sides of the block. Does that tell me I should be OK?
I have used the air pressure to barrel for years, it's fast ,easy and it work's.
I put a ear plug into the chamber and then put in a empty case, it holds the plug snug with my left hand. Blow into barrel while turning the block, have the gas block somewhat snug so it stays where you put it when you get the most amount of air through the barrel.
I put a ear plug into the chamber and then put in a empty case, it holds the plug snug with my left hand. Blow into barrel while turning the block, have the gas block somewhat snug so it stays where you put it when you get the most amount of air through the barrel.
