Colt 2 piece 9mm magwell installation

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[ARCHIVED THREAD] - Colt 2 piece 9mm magwell installation

Posted: 10/6/2018 10:52:31 AM EDT

I just got a colt 9mm SMG kit. Is mounting them in a receiver a complex experience dependent task, or can a good machinist/gunsmith do it? The blocks have been drilled when they were in the original SMG. JT doesn’t want to do it because they’ve been drilled. It looks like M60 joe isn’t working. Is it as simple as putting the springs on the blocks, pushing the blocks to the top of the magwell and drilling pinning in a place that hasn’t been drilled?

Posted: 10/6/2018 7:43:50 PM EDT

[#1]

I reverse engineered mine. Measured the hole locations on the blocks and then transferred those measurements to the lower and drilled the holes. Lined up perfect, pins went in nicely.

Posted: 10/7/2018 12:40:45 PM EDT

[#2]

Quote History

Quoted:
I reverse engineered mine. Measured the hole locations on the blocks and then transferred those measurements to the lower and drilled the holes. Lined up perfect, pins went in nicely.

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That sounds tough. A few thousandths of an inch variance would be bad. What do you think about filling the block holes with JB weld and then measuring and drilling?

Posted: 10/7/2018 1:01:31 PM EDT

[#3]

Quote History

Quoted:

That sounds tough. A few thousandths of an inch variance would be bad. What do you think about filling the block holes with JB weld and then measuring and drilling?

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I'd think that would be more than adequate.

Posted: 10/7/2018 1:19:07 PM EDT

[#4]

JT just said the JB Weld is too soft. Back to the drawing board.

Posted: 10/7/2018 2:07:16 PM EDT

[#5]

Even with drilling the pin holes in a different location in the blocks? I really can't see how that would be a problem.

Posted: 10/7/2018 9:35:37 PM EDT

[#6]

Quote History

Quoted:
JT just said the JB Weld is too soft. Back to the drawing board.

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http://www.itwconsumer.com/devcon-products/product.cfm?id=Plastic%20Steel%C2%AE%20%20Epoxy%2C%202%20oz%2E-50

Devcon Plastic Steel

Posted: 10/8/2018 3:27:23 PM EDT

[#7]

Don't try to line up the old holes drill new ones...

You can get by with one pin in each block Colt did this on some 9mm AR's...

Here is a lower I installed a two piece block in...

Posted: 10/8/2018 5:50:57 PM EDT

[#8]

Are there any tricks or concerns with positioning the blocks high or low in the magwell?

Posted: 10/8/2018 6:30:50 PM EDT

[#9]

Yes,

Blocks have to be positioned correctly because they contain the ejector and feed ramp.

I ditched the two piece mag block and ended up buying a Colt 9mm Carbine lower with a pinned one piece mag block.

Posted: 10/8/2018 6:41:59 PM EDT

[#10]

Save yourself the headache man.

Get one piece block from Brownells (Colt) --> Colt Dedicated 9mm AR15 conversion block - one piece

Posted: 10/9/2018 10:13:44 PM EDT

[#11]

New holes seem like it should be fine...

Posted: 10/11/2018 12:43:32 PM EDT

[#12]

Specialized armament

Posted: 10/11/2018 6:33:43 PM EDT

[#13]

Does anyone know if the 4 springs are needed for function? I found some if I end up going this route, but would have to order them.

Posted: 10/14/2018 6:27:55 AM EDT

[#14]

Quote History

Quoted:
Does anyone know if the 4 springs are needed for function? I found some if I end up going this route, but would have to order them.

View Quote

Not sure if they are needed but Colt did use them so I suppose they serve some type of purpose... I did use the ones that came in my 9mm SMG kit when I installed them in my lower... If you don't have a mill or a drill press I wouldn't attempt installing them... For my install I used one of my 80% AR-15 drilling/milling jig plates as a fixture to hold the lower on my mill's table... It's a easy task if you have the right tools you can screw up a lower and the blocks if you don't... A Hahn bottom load block is a good option they are expensive but they work well... The link to the Colt one piece block is a good price but it needs pinned in also... I've tried a couple others that were cheaper PSA and C-Products but they sucked the fixed ejectors always worked loose and wouldn't stay adjusted for reliable ejection... Before I did mine I got a quote from M60Joe for $60 plus shipping to install a set of Colt 2 piece block in a lower...

Posted: 10/14/2018 12:56:23 PM EDT

[#15]

What about putting some tack welds over the holes?

Posted: 10/15/2018 7:16:23 PM EDT

[#16]

I think I’m way over thinking it. KISS would be new holes. I’ve got the springs coming from numrich. Engraving the receiver is about a 2 week deal. If these don’t sell, I’ll chose one of the options and go for it. By “I’ll go for it” I mean I will take it to a very talented gunsmith/machinist friend.

Posted: 10/19/2018 10:21:24 PM EDT

[#17]

My friend was able to hit the holes. The mag blocks are in and look positioned perfectly. The DOE upper mad with real colt SMG parts and reproduction front sight assembly and handguards will be back from Retro Arms Works Monday. I don’t know why, but I like the 3 roll pin in the lower receiver look. Probably because it looks retro. There are definitely easier options.

I refinished the lower with Norrel moly resin grayish flat black. It looks like it will be a great match for the upper, but won’t be sure until Monday. Thanks to all for the help and responses.

Posted: 10/20/2018 7:49:40 AM EDT

[#18]

Excellent post some pictures when you get it all put together...

[ARCHIVED THREAD] - Colt 2 piece 9mm magwell installation

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