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Posted: 2/25/2015 8:31:15 PM EDT
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Brownells sells a Colt brand 9mm upper, slab side, A1 sights (Mfr Part: SP62908). Is the only thing keeping this from being useable for 5.56 the lack of the gas tube hole in the front? Or are the other differences besides that. It would be super easy to add the hole. Thanks, it's getting hard to find uppers like this.
http://www.brownells.com/userdocs/skus/l_160302052_2.jpg http://www.brownells.com/userdocs/skus/l_160302052_5..jpg http://www.brownells.com/userdocs/skus/l_160302052_4.jpg |
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The bump is part of the forging for the rough blank upper. Cheaper to leave that in than make whole new dies for an otherwise barely changed 9mm upper. The notch on the inside is an extra milling step that's not needed for 9mm, so it's cheaper to leave it out.
However, this picture seems to show the lower rail having the notch. There's no reason they would only partially do that milling process, so it's possible some of these have the notch and some do not. 
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I was joking. Posted Via AR15.Com Mobile Quoted:
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Why has that ruined anything for you? It's not an auction that someone took out from under you. It's a product, on a website, which they seem to have multiples of. . . ? I was joking. Posted Via AR15.Com Mobile LOL. I was sitting here wondering if you were serious or not. Probably should have used a  followed by a  or .......and I'll leave with a 
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I just looked at one of my old uppers, and it looks like the radius of the pin cut is slightly larger than a 5/8" endmill. The cut is also corner radiused in the very bottom, or top if the receiver is in the "as used" position. That would require an endmill that has a corner radius on it. Wouldn't be too hard to do. I wonder if just plunging a 5/8" endmill would be sufficient clearance, or if you'd have to interpolate the cut to get it to exactly the size of an original cut.....looks like the diameter of the pocket might be about .650 or so instead of .625.
There are any number of machinist here that could do that, me included. Question I have would be if there is enough wall thickness to get the cut to the same depth that is on an upper that does have that cut.........wouldn't want to break out the top/side of the receiver. That cut is the reason for having the rectangle boss on the outside of the left side of the receiver. |
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We did not put the gas tube hole or cam pin cut on the 9mm uppers we made.
But they sold so poorly that we ended up putting the remaining "in the white" inventory back on the CNC to turn them into 604's. As far as NDS-635 lowers, we won't be doing any more of those either. They only reason we were able to sell them was the panic buying after Sandy Hook. |
| I have an old large hole Colt 9mm upper that someone converted for use to 5.56 by drilling a hole for the gas tube and using a mill for the cam pin notch. I assume that it worked without issue and I may in fact use that upper for 12.5" lightweight build in the future. Still sitting in the parts bin for now. |
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Lookin' good. Here's your 9mm's cousin: http://i1239.photobucket.com/albums/ff502/photocumulus/AR15Com/635Right.jpg im jelly! |
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im jelly! Quoted:
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Lookin' good. Here's your 9mm's cousin: http://i1239.photobucket.com/albums/ff502/photocumulus/AR15Com/635Right.jpg im jelly! Details on yours: Your magblock is pinned, Y/N? What are you plans for bolt carrier? DOE? |
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Lookin' good. Here's your 9mm's cousin: http://i1239.photobucket.com/albums/ff502/photocumulus/AR15Com/635Right.jpg You sure could use a DOE barrel assembly for that fine build liemohnmanufacturing.com has got some
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You sure could use a DOE barrel assembly for that fine build liemohnmanufacturing.com has got some
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Lookin' good. Here's your 9mm's cousin: http://i1239.photobucket.com/albums/ff502/photocumulus/AR15Com/635Right.jpg You sure could use a DOE barrel assembly for that fine build liemohnmanufacturing.com has got some
Linky no worky? 
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Linky no worky? Quoted:
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Lookin' good. Here's your 9mm's cousin: http://i1239.photobucket.com/albums/ff502/photocumulus/AR15Com/635Right.jpg You sure could use a DOE barrel assembly for that fine build liemohnmanufacturing.com has got some
Linky no worky? http://liemohnmfg.com/ |
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try this one.
http://liemohnmfg.com/ story of my life........day late or a dollar short. |
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