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View Full Version : Gas hole allignment in bbl vs front sight


19kilo
March 25, 2002, 22:40
I just drilled out my gas hole in my bbl and my Brit front sight to .113 this is for a 16.75" bbl. I need to know how the hell do I align the gas openings with each other? I pounded on the bbl and tried to line up the two holes in the GB.(hand guard & drift pin) but it seems that the grooves in the bbl were drilled for a different block. one is too far left and the other is too far right. If I cover the muzzle and blow into the breech I get blasted with air and metal shavings from the gas tube. Do I just continue w/the assembly and hope?
TANKS
Tim

HD99FXR3
March 26, 2002, 09:21
probably should have left gas block on barrel and used it as a guide, so much for hind sight. when you blow through barrel is gas block aligned with retaining pin grooves already on barrel? or is it aligned with hole you drilled? and does both holes line up or is one partially blocking hole in barrel?you should be able to see this by removing front sight pin/post. if you are aligned w/ grooves then i would remove front sight pin and carefully redrill gas port. i'm pretty far out on a limb here because i don't have a inch pattern rifle to look at, it might be possible to redrill locking pin grooves but only if when looking in holes in gas block you see nothing but steel if you see any part of old grooves through holes then your only recourse is to align old grooves to holes in gas block and redrill using gas block as guide to at least get location of hole in right place on barrel.boy what a can of worms.

1006587
March 26, 2002, 10:16
The gas port on the Inch barrels is at an angle thru the vent hole and not through the sight hole as on a Metric gas block.

milton
March 26, 2002, 10:52
I'm playing this game as well. TAPCO missing part kit - right? Last night I installed my gas block by heating the block in the oven at 550 for a half hour with the barrel in the freezer. The gas block slipped on about half way, from there I used a brass drift and a hammer. Got the gas block to line up by running a piece of of straw down the front sight gas port down into the barrel. A few taps from a plastic deadblow hammer did the adjusting. I had to ream out the barrel's gas block mounting pin hole a little bit to allow for the new tapered pin. The hand guard screw hole was real close, but also needed to be touched up. Doubled checked the gas passage and drove the new pin home. Everything is nice and tight. Also, the port lines up, but I will have to open it up some for the 16.5" new barrel length now that the gas block is mounted. Have you installed the mounting pin? If not, you may need to locate the gas port by a piece of straw/wire and a little tapping with a hammer. Also, what type of mounting pin are you trying to use? I think you need a tappered one. If you need one, send me an e-mail. I ended up buying a box of 50. I used 3 last night, before I got the taper right on the barrel's retaining grove. Best of luck.

HD99FXR3
March 26, 2002, 10:58
The gas port on the Inch barrels is at an angle thru the vent hole and not through the sight hole as on a Metric gas block. i did say i was pretty far out on the limb. i was pretty sure somebody would come along and saw it off. and they did. :D

19kilo
March 26, 2002, 22:50
Milton, dam good advice on the straw/wire. And yes, you win the million dollar "psychic" award of the year...it is one of the Tapco specials. I did not think about the freezer/oven deal. I just put the bbl muzzle down in my vise and adjusted the jaws to touch only the GB and then beat the shit out of it. I made a 16.75" bbl out of mine, just because I made my cut directly behind that evil bayonet lug! I have not put the taper pin in yet at this time. My thougt was just to chuck up a steel screw and turn it while holding a file to remove necessary material.
This length of bbl sticking out from the massive clutches of my Izzy HG with no muzzle break just looks killer! I will post pics of final project later in the next 3 weeks or so.
I also had to drill out the remains of the bbl grooves. They did not align with the holes in my GB.
Good Luck on yours!
Tim