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9/22/2017 12:11:25 AM
Posted: 9/14/2005 6:36:47 PM EDT
[Last Edit: 9/14/2005 6:37:55 PM EDT by glenn_r]
I'm combining a DPMS gas tube with a YHM flip-sight gas block. When it'sassembled & lined up for the pin, the gas hole doesn't line up perfectly with the hole in the gas block--they're maybe 1/3 mm off. Is this normal, or likely to be a problem?
Link Posted: 9/14/2005 7:37:39 PM EDT
I see this kind of thing all the time.
My solution is to drill through the gas block and into the gas tube with a 0.081" drill bit.
That is 0.002" undersized for the roll pin still.
The drill will cut away the offending metal and you will have a much easier time installing the pin.
The 0.002" press fit on the pin will keep it in place just fine.
This is best done on a drill press so that the bit does not grab/break/oggle out the hole larger than 0.081"
Any of that would be bad...

Randall Rausch
www.ar15barrels.com
Link Posted: 9/14/2005 7:48:20 PM EDT

Originally Posted By Randall_Rausch:
The drill will cut away the offending metal and you will have a much easier time installing the pin.



I already have them pinned together, but the gas holes don't line up perfectly. You recommend I re-drill the pin hole instead of the gas hole? I don't have a drill press

Is there a standard distance between the pin hole and gas hole? Or is this another thing like the pins on the front sight base, where the thing is just drilled--wherever the hole ends up is fine?
Link Posted: 9/14/2005 8:37:38 PM EDT
Oh, you mean that the large gas hole in the gas tube does not align inside the gas block?
That's OK, those holes are usually 1/8", but the gas port hole in the barrel is more like 1/16" to 0.090" so ot's ok if they are off 1/2 mm.

How is that for the intermixing of measurement systems?

Randall
Link Posted: 9/15/2005 12:51:37 AM EDT
I had problems with a bunch of DPMS tubes I bought. They did not have enough offset in them and the offset was not true. When I put them against a straight edge it was easy to see the problem I had. I sent them back and got a few from Bushmaster.
Link Posted: 9/15/2005 6:01:21 AM EDT

Originally Posted By Randall_Rausch:
How is that for the intermixing of measurement systems?





thanks for the help!
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