FYI: GM has some pretty good barrels available

[MarinePMI]

FYI for those doing builds...

MILITARY BARRELS - AR-15 / M16 / M4 Rifle Barrels - Green Mountain Rifle Barrel Co.

 

[BCP]

They seem really cheap compared to DDefense. How well do they shoot? 2-3MOA? And do they usually have the gas port, chamber, everything all good to go? Lots of cheap companies seem to get that stuff wrong.

 

[MarinePMI]

GM is the company that supplies most of the large vendors and government contracts. (Largest barrel manufacturer in the US actually.) What they sell are usually contract over runs, hence the cheap prices.

The ones I have from them have shot VERY well, and come with the gas port already drilled. They literally are a "drop in/bolt together" item.

 

[bowslngr]

I recently built two ARs using GM's 16" chrome lined, M4 profile barrels for my kids. With a three power red dot sight (Burris AR332) I am able to put 10 rounds inside 1-1/2" at 100 yds.

 

[McLarenross]

GM is great. Ive used their barrels for a number of applications and they always shoot.

 

[Ballista One]

GM is a solid company. Everyone who has a Colt rifle or carbine with a "G" on the chamber swell has a GM barrel. Lots of them out there...