Quote Originally Posted by Pappabear View Post
I'd ship that mofo back to LMT, I bet they just give you a new barrel. No excuse for that nonsense.
Not sure I'm there yet... Per ED
- it's a 12-13 year old rifle
- that shot respectably for what it was as shipped by the factory
- that did not show a problem until a 3rd party product weighing several ounces was hung on the muzzle, after removing the factory muzzle device

Quote Originally Posted by Eurodriver View Post
My LMT barrel is legit. 2” groups at 100y with a red dot and M193. I’m very happy with it. That’s with a Vortex FH.

Add the AAC and get these results. Somethings not right and the threads point to it being an issue.
Maybe there is an LMT issue with the threads. Not sure there is a TDP spec for this... Seems like more of a defacto standard that AAC has latched onto. (But I could be entirely wrong there, I just have not seen a standard other than AAC's)

But this feels to me a bit like a niche version of the undocumented standards issue similar to the BCM Magpul problem.

The forums are full of "I can't get my threads right for my can mount" type posts with people making various barrels. So it's not like this is a slam dunk that everyone has right.

If it shot fine with the muzzle device, but not the can, then seems to me like more fault isolation would be appropriate before declaring LMT "garbage ass". Was this a complete Defender upper? Barrel nut unmolested?

If a brand new unmolested rifle made in a era where can use is prevalent and there are now well-documented standards, I might try to take it back to LMT.

But for a rifle made in 2007 that shot fine until I hung a can on it? If I think the threads truly are the issue I'd do as some wise soul already suggested, get the AAC muzzle specs, have the muzzle re-crowned and the threads cut back and move on with life.

20 MOA also seems like more than poor barrel mfg... I'd be checking barrel nut, muzzle crown, baffle strikes, etc.

Not saying there may not be an LMT issue, just that I'm not sure I'm ready to declare them "Garbage Ass" and immediately at fault based on what has been shared.