Thread size for Sportsmans Guide AR15 barrel

[one918]

So I bought the 16" M4 Sportsmans Guide M4 barrel after reading all the positive comments on their website. The details didn't say anything about the thread size for the muzzle brake so I just got a standard 1/2 x 28. Well the muzzle brake would not thread on. I added some oil and it still will not thread on.

Does anyone have experience with these barrels? Is there something I'm missing. This is my second build. First I did not have any problems threading on the muzzle brake.

Thanks in advance.

[ar15barrels]

What is the diameter of the threads?

[TKM]

I'm pretty sure those are Mossberg barrels. Standard 1/2x28 threads.

Try another muzzle brake.

[kcstott]

Or take a look at the threads and make sure the end isn't all buggered up.

[one918]

So it was the muzzle brake. I used a different a2 bird cage from another build and it threaded fine.

However, now using the crush washer, I would have to tighten the muzzle brake 180 degrees to get the covered end on the underside of the barrel. From what I gather, it's not supposed to be tighten more than like 90 degrees or 15-20 ft lbs

[timmyboy450]

You can get that turned 180 degrees just do it in steps. Tighten a little then back off only crushing washer a little at a time until you get it where you want. If you had to go more than 3/4 turn I usually use a different washer.

[ar15barrels]

However, now using the crush washer, I would have to tighten the muzzle brake 180 degrees to get the covered end on the underside of the barrel. From what I gather, it's not supposed to be tighten more than like 90 degrees or 15-20 ft lbs

Minimum 90 degrees.
Maximum 450 degrees.