MMC Armory (Minnies Machine Company) Gov Contract 14.5” Socom Barrels

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Originally Posted by georgeib

Sorry in advance if this is a dumb question. Is there a way to test the chamber to see if it's Wylde or NATO before buying the reamer?

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Ned also sells a gage, this is the description from his site…


This gage tells you if you have a chamber that is 5.56 NATO (or larger), or something shorter/smaller.

The gage looks a lot like a headspace gage but it does not gage headspace. It comes with its own rod which you thread into the tapped hole in the back of the gage. Unload and open your rifle, pull the bolt group, make sure the chamber is clean so there is no false reading, and drop the gage in. If the gage's shoulder "clinks" off on the shoulder of the chamber and the gage drops or pulls free without sticking or resistance, you have a chamber that is 5.56 NATO or larger. If the gage goes in and wants to stick, as in, you let it in and it pulls with a little resistance, or you try and turn it but it does not turn freely, you are short of 5.56 NATO and probably have a .223 chamber. You can color it up with a Sharpie, put it in and spin it (clockwise) to observe where it's contacting the chamber first.

Note that the gage will also stick in a .223 Wylde chamber since the Wylde's freebore is smaller in diameter than the 5.56 NATO's. It's my opinion that the Wylde chamber ought to be OK with 5.56 NATO ammo, but I have not delved into this scientifically. I don't own anything with the Wylde chamber, so I have no first-hand experience with it. The smaller freebore, I suppose, would make it more crud-sensitive.

The newly designed (3/15) handle acts as a case for the gage, preventing loss and damage.

Probing either a .223 SAAMI or .223 Wylde chamber with this gage will not harm the chamber unless you decide to really try by hammering it in. Don't do that.

FWIW, I do have a Wylde chambered barrel that I've successfully shot factory loaded 5.56 Barnes 70gr, Black Hills 70 gr GMX, and IMI 77 gr SMK. I was curious if there'd be pressure signs, so I examined all the cases and didn't find any. I do keep this barrel fairly clean however.

Mark, don't know if you've already tried this, but give the barrel a solid cleaning with special attention to the throat, and try again? Would suck if it was something that simply, and you end up buying a $270 throat scraper...

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Originally Posted by georgeib

Mark, don't know if you've already tried this, but give the barrel a solid cleaning with special attention to the throat, and try again? Would suck if it was something that simply, and you end up buying a $270 throat scraper...

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I did. Still had pressure issues. I suppose the reamer would be a high class carbon ring remover if that were the case. I'm not a big subscriber to the carbon ring thing because I've never had the issue in 30 years of AR shooting, but It's still a possibility.

And I can't remember if when the MMC barrel was new if it immediatley shot significantly faster than my other ARs. I don't think we were concerned with velocity and just assumed it to be another 14.5 in the bunch.

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Originally Posted by markm

I did. Still had pressure issues. I suppose the reamer would be a high class carbon ring remover if that were the case. I'm not a big subscriber to the carbon ring thing because I've never had the issue in 30 years of AR shooting, but It's still a possibility.

And I can't remember if when the MMC barrel was new if it immediatley shot significantly faster than my other ARs. I don't think we were concerned with velocity and just assumed it to be another 14.5 in the bunch.

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Will the reamer properly size the chamber, or just the throat? If just the throat, would you be better off re-reaming the whole chamber and throat, or is this already getting to be too much trouble?

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Originally Posted by georgeib

Will the reamer properly size the chamber, or just the throat? If just the throat, would you be better off re-reaming the whole chamber and throat, or is this already getting to be too much trouble?

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The reamer appears to just fixes the leade. That's the problem area according to Ned's experience with various manufacturers that aren't named Colt. Based on my chrono testing, I could really probably use this on a few of my non-Colt barrels. My 2 Colt barrels did indeed show the slowest velocities which now makes sense.