GM-M29 barrel

[titsonritz]

Sounds like a good barrel for a MK18 chop.

[1168]

Yeah, the SPR IS such a different type of barrel that I’m not sure it would teach me much about this project.

In your pic the GM-M29 looks to be profiled sort of between the “SOCOM” and “Gov’t”, which would be cool.

You should. They make good barrels. Well worth your time to try out what you have at least and form your own opinion.

These are all Colt carbine uppers / barrel assemblies as they came from complete factory carbines with nothing added, swapped out, or exchanged for a different part. Only removed the hand guards for the picture...



The one in the middle has a Green Mountain barrel with same profile as what you are looking at.

A green Mountain barrel that Colt decided to source / contract and use on some of their carbines that they were selling to the general public...

[Circle_10]

You should. They make good barrels. Well worth your time to try out what you have at least and form your own opinion.

These are all Colt carbine uppers / barrel assemblies as they came from complete factory carbines with nothing added, swapped out, or exchanged for a different part. Only removed the hand guards for the picture...



The one in the middle has a Green Mountain barrel with same profile as what you are looking at.

A green Mountain barrel that Colt decided to source / contract and use on some of their carbines that they were selling to the general public...

What factory Colt carbines had this barrel profile on them?

[Steve-0-]

Green Mountain tends to sell excess barrels they make for companies. Hence why you can get almost any sionics, sig or colt spec'd barrel from them, lol.

[JediGuy]

Green Mountain tends to sell excess barrels they make for companies. Hence why you can get almost any sionics, sig or colt spec'd barrel from them, lol.

Do they hog out the gas port on all?
If memory serves, you would know where Sionics sourced barrels, but they are known for their appropriate and intentionally small gas ports, versus GM typically (according to the internet) having large.

[1168]

Green Mountain tends to sell excess barrels they make for companies. Hence why you can get almost any sionics, sig or colt spec'd barrel from them, lol.

One thing I’ve noticed is that some of their barrels look an awful lot like some more well known brands. Such as the GM-M19, which has a similar profile to one of the CHF barrels that are hard to find, although it is button rifled.

[Steve-0-]

Do they hog out the gas port on all?
If memory serves, you would know where Sionics sourced barrels, but they are known for their appropriate and intentionally small gas ports, versus GM typically (according to the internet) having large.

The 18" rifle barrels are all 0995, not positive on other over runs but they arent shy about telling you a port size if you call them. Might be on hold for a minute though, lol.

[JediGuy]

The 18" rifle barrels are all 0995, not positive on other over runs but they arent shy about telling you a port size if you call them. Might be on hold for a minute though, lol.

Once I thought about it and started looking at their barrels (again), I realized that...



...they are very responsive and not shy.

[1168]

Well, those are rather big. I’ve e-mailed them about the port sizes on the GM-M29 and GM-M19.

[JediGuy]

Yes.

Things like the BRT gas tube are great to fix something you already have, or maybe tune a slightly large port. But I don’t think there’s much point in getting a barrel that is substantially off where it should be.