Your methods of aligning gas blocks

[dang472]

Obviously the gas block bottoms out against the step in the barrel, but what do you guys do to make sure it's 100% straight and aligned with the gas port? I already aligned one that had a rail on top, that was easy. What about the low-pro blocks? Is it a trial and error thing where if it doesn't cycle properly, you reposition the gas block a little?

 

[cmh2007]

I actually have a gun that aligns at over .1 from the step, but for aligning side to side, eyeball it, and if it needs a little tweaking then tweak it. if its not straight you can actually feel it when you cycle the bolt.

 

[MPrimo]

I use a Sharpie to mark the barrel (at the shoulder) and the gas block. Small tick marks ... then just line up the lines.

 

[msalm]

I use a bore scope! Perfect every time.

 

[Temp9]

Many gas block/barrel combos align short of the step to allow for the front handguard cap if so desired. I use a pencil to draw a line down the center of the gas port, eyeball the distance away from the step in the barrel, then straighten the gas block relative to the line I drew. Easy peasy. If you want to check, plug up the chamber with a spent cartridge, shove an air compressor nozzle in the muzzle (careful not to damage the crown), and see if air is coming out of the gas tube.

 

[Big Z]

Eyeball it for left/right. I check with calipers beforehand to see if I need to pull the gas block away from the step.

 

[BigBlue&Goldie]

I eyeball it.......the human eye is more sensitive than people give it credit. You should be able to tell if your gas tube is perfectly centered as it will have slight wiggle room as it is slightly smaller in diameter than the port it slide into in the upper.

To make sure the holes line up, I stick my finger in the chamber and blow air through the muzzle; if there is sufficient airflow through the gas tube, you should be good to go. I have built many uppers and never had one not function 100%.

 

[Brasscow]

Often it doesn't butt up to the step in the barrel. Get a drilling rig and dimple your barrel.

 

[dang472]

I like the compressed air and/or bore light idea. I'll measure the front and back distance, but I was curious how you guys did the side to side alignment since the gas port to block hole is a blind proposition. Thanks for the replys.

 

[Dtarget]

I use a shim and usually buy barrels with a gas block dimple.

 

[Blazin]

I use small pencil marks on the barrel and the gas block. Once I'm done I lick my finger and rub the pencil marks away. Voila!

 

[flysolo]

I actually have a gun that aligns at over .1 from the step, but for aligning side to side, eyeball it, and if it needs a little tweaking then tweak it. if its not straight you can actually feel it when you cycle the bolt.

How do you feel a misaligned gas block by cycling the bolt? That's some serious kung-fu there!

 

[user]

Bore Scope. Kick Ass way of doing it.

 

[cmh2007]

at least on my three i could feel it make contact with the gas key really bad if it was misaligned too far. you can feel it drag on it too

 

[346ci]

Most barrels I use have the dimple.

Rainier Arms sells a jig for barrels that don't have them. Works great.

 

[smschulz]

I use pencil marks even though all the barrels have a dimple and check with micrometer. I also dimple the second screw hole once I get it aligned.

 

[Outlaw45]

tag for later

 

[Rigamortous]

I use the scribe method, works for me