FM9 Lower Buffer Tube issue

[rougeqc21]

Putting together a FM9 lower and started to install a 2A armament AR10 milspec buffer tube. I get about one rotation in and then the two no longer screws in and binds up. I happen to have two brand new buffer assemblies and both behave the exact same way. I'm wondering if anyone is encountered this with these lowers?

 

Also, for good measure, I tried installing the tube into an Aero lower that I have and they install fine.

Edited August 30, 2020 by rougeqc21

[RaylanGivens]

@rougeqc21

 

Check the threads in the lower...  Maybe partially threaded or some junk bound up in it...  If the threads look good check to see if it was dropped and the thread area is deformed.

 

[rougeqc21]

Turns out there was too much ano on the threads and they needed to be cleaned up @RaylanGivens.

Took it to a local smith who put a tap on the receiver and removed some ano from some of the threads and voila, buffer fit like a glove!

Mystery solved.