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Posted: 11/21/2014 8:56:11 PM EDT
[Last Edit: 11/21/2014 8:56:30 PM EDT by VA-BlkRifle]

asked in pistol forum, but I need to know wtf is this, pin pressed into wall of extension opposite the hole Is this right? I don't recall seeing anything like this, hole measures 0.190"
Link Posted: 11/21/2014 8:58:34 PM EDT
Originally Posted By VA-BlkRifle:
http://www.ar15.com/media/viewFile.html?i=70517
asked in pistol forum, but I need to know wtf is this, pin pressed into wall of extension opposite the hole Is this right? I don't recall seeing anything like this, hole measures 0.190"
View Quote

Looks like it would prevent the bolt from locking in place. Something to disable the rifle/barrel?
Link Posted: 11/21/2014 8:59:51 PM EDT
well that's a bit fucked up, as I just bought this for a pistol build.
Link Posted: 11/21/2014 9:00:20 PM EDT
Maybe this support pin
Link Posted: 11/21/2014 9:01:57 PM EDT
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By VA-BlkRifle:
well that's a bit fucked up, as I just bought this for a pistol build.
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Have you tried fitting a bolt? I was just guessing.
Link Posted: 11/21/2014 9:03:28 PM EDT
I should add this is a 7.5" barrel
Link Posted: 11/21/2014 9:03:49 PM EDT
I can try a bolt right now
Link Posted: 11/21/2014 9:03:55 PM EDT
Sig barrel?
Link Posted: 11/21/2014 9:04:34 PM EDT
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By ICEMAN19047:
Maybe this support pin
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Interesting, never heard of such a thing.

OP's barrel does look like that though...
Link Posted: 11/21/2014 9:06:08 PM EDT
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Originally Posted By CROWDLG:
Sig barrel?
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I'm going with this.
Link Posted: 11/21/2014 9:07:33 PM EDT
[Last Edit: 11/21/2014 9:08:04 PM EDT by VA-BlkRifle]
it's from Green Mountain Rifle Barrels, and the extractor lug only will turn over that pin, so I guess that's right?
Link Posted: 11/21/2014 9:09:08 PM EDT
The reason for the hole is so that upon machining for the pin a shouldered hole can be made; the pin has a step to control its protrusion. As for the purpose of the pin itself, I'm currently at a loss.
Link Posted: 11/21/2014 9:10:03 PM EDT
[Last Edit: 11/21/2014 9:11:32 PM EDT by VA-BlkRifle]
now that I'm going back and looking at the website, it clearly shows it too. It keeps the extractor from getting too loose too fast on an overgassed system apparently
Link Posted: 11/21/2014 9:10:10 PM EDT
Well that's cool I guess.

I built a rifle with one of their barrels recently, couldn't be happier btw, and I didn't get an extractor support pin.

Not sure if I'm jealous, but I wonder if it was a production over run.
Link Posted: 11/21/2014 9:10:33 PM EDT
[Last Edit: 11/21/2014 9:13:58 PM EDT by zegermanznew]
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By VA-BlkRifle:
it's from Green Mountain Rifle Barrels, and the extractor lug only will turn over that pin, so I guess that's right?
View Quote


I was just about to guess it was a GMR.

I have the exact same 7.5" barrel, same hole. I found no answer anywhere, and tried the same threads in GD, pistol, build etc. No one knows.

I just built it and shot it. It works.

ETA: After reading thread, I am still intrigued, and have even MORE questions than I did before. Im gonna go read more.
Link Posted: 11/21/2014 9:12:18 PM EDT
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By ArimoDave:
The reason for the hole is so that upon machining for the pin a shouldered hole can be made; the pin has a step to control its protrusion. As for the purpose of the pin itself, I'm currently at a loss.
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I guess it helps with extraction somehow.
Link Posted: 11/21/2014 9:13:06 PM EDT
[Last Edit: 11/21/2014 9:14:02 PM EDT by VA-BlkRifle]
yeah I'm gonna try it, my third barrel from GMR
Link Posted: 11/21/2014 9:14:21 PM EDT
The other thread says that the pin is to support the extractor during the higher unlock speed due to a short gassed barrel. It keeps the extractor from losing its grip on the case rim while it is in the chamber. I'd guess that you'd only see it on super short barrels.

Posted Via AR15.Com Mobile
Link Posted: 11/21/2014 9:16:15 PM EDT
Did you pound it on the ground? The end looks banged up a bit.
Link Posted: 11/21/2014 9:19:00 PM EDT
[Last Edit: 11/21/2014 9:19:45 PM EDT by VA-BlkRifle]
i did drop it about two and a half feet onto vinyl tile but that all wiped off no dings. I'm off to mount it
Link Posted: 11/21/2014 9:33:57 PM EDT
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By VA-BlkRifle:
i did drop it about two and a half feet onto vinyl tile but that all wiped off no dings. I'm off to mount it
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STS! Enjoy!
Link Posted: 11/21/2014 10:24:07 PM EDT
[Last Edit: 11/21/2014 10:24:17 PM EDT by VA-BlkRifle]
Link Posted: 11/21/2014 10:32:08 PM EDT
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By VA-BlkRifle:
http://www.ar15.com/media/viewFile.html?i=70522
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Ugh, I have a headache just looking at it.

Link Posted: 11/21/2014 10:47:29 PM EDT
[Last Edit: 11/21/2014 10:49:42 PM EDT by VA-BlkRifle]
I suspect it's gonna be that way

AR equivalent of a snubnose?
Link Posted: 11/26/2014 1:46:40 PM EDT
VA, didja get to the range yet? I have one of those barrels on the way, I'm curious how yours shoots.
Link Posted: 11/29/2014 6:14:16 AM EDT
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