gas block alignment ?

[JMO57]

traded somewhere on the net for a G1 kit, worked along and along with it. did a search here on gas block r&r . Last night decided to install the gas block (previously owner disassembled kit completely).
put barrell in the freezer for an hour, drove the block on . the only thing i had laying around that would fit the gas hole was a hex wrench. rotated the block by tapping until the hex wrench would pass all the way and could be seen in the barrell.

questions:
1) how will this affect the cycling when the gun is built? (in other words the gas hole in the barrell and the hole in the block are aligned by a hex wrench). does the hole need to be perfect in alignment?

2) my kit didn't have the larger pin that holds the block on the barrell, only the smaller pin. where do i get one for a G1?


wecsog observations: i work away from home (and my tools) during the week. i tried to remove the front site with gem clips, coat hangers, nails. finally took 2 ball point pens and removed it right away. also found an old 2x4 about 4 ' long under my rental place, place the threaded end of the barrell on the wooden deck and drove the gas block on with the 2x4.

[Stoney]

The large hole is for the hand guard bolt

[Scott S]

If the gas block retaining pin hole (the smaller of the two holes that run left to right thru the block) lines up with the corresponding shallow cut in the top of the barrel and you can drive the pin into the hole, then everything should be aligned correctly. If the gas I say "should" in case the gas block isn't the original. If that's the case, report here and we'll advise.

[Court in Fl]

1) how will this affect the cycling when the gun is built? (in other words the gas hole in the barrell and the hole in the block are aligned by a hex wrench). does the hole need to be perfect in alignment?

I think as long as the hex wrench was a good fit in the hole you should be ok.

Only one pin holds the gas block in place.
Are you saying it's to small ?


Court in FL.

[JMO57]

the small retaining pin does fit .
the hex wrench does drop thru the inside of the barrell it just seems like i can feel a little ledge starting it into the barrell, but i read here somewhere the hole in the barrell is smaller than the hole in the block. i would assume the design engineers did this for a reason.
i read the posts where you can drill it if you are not sure of the alignment, but not having precise equipment i would rather not hand drill it and wallow or egg shape the hole.

thanks

[Jambo]

I don't if it's just luck or if the gas block and the barrel has some sort of memory or I'm just damn good, but I get my gas block aligned perfectly everytime. By memory, it almost seems like the gas block wants to align just right. Well, now, I don't think I get it aligned perfectly everytime, but you can tell that it's lined up close enough that the pin will go in just fine. What I think what's happening is the gas block may be canted like a fraction of a degree or so and it aligns itself when I drive the pin in. Now, I don't know about driving the pin out from right to left or left to right, but my gas block and barrel doesn't seem to mind either way.

[fire for effect]

Originally posted by JMO57
the small retaining pin does fit .
the hex wrench does drop thru the inside of the barrell it just seems like i can feel a little ledge starting it into the barrell, but i read here somewhere the hole in the barrell is smaller than the hole in the block. i would assume the design engineers did this for a reason.
i read the posts where you can drill it if you are not sure of the alignment, but not having precise equipment i would rather not hand drill it and wallow or egg shape the hole.

thanks
Yes the hole in the Gas Block is larger then the gas port in the barrel The gas port in the barrel is the metering device, the hole in the gas block is merly a conduit, redirecting the gas to the face of the piston. It does not matter if the two holes are concentric or not, the gas doesn't mind.