Muzzle brake issue - seized up

[ljk]

It's on a SBR lower so no worries about legality, it's 14.5" now. My only concern on length is whether I can clear the rail with my suppressor. I've measured the OD of the undamaged threads on the barrel with a set of dial calipers and two different micrometers and I'm getting between .5025"-.503" which is larger than they should be. I'm hoping Rainier will replace the barrel for me.

it's not a proper way to measure the major dia. of the thread. find someone with a +/- reamer set, drill and ream a hole through a piece of 1/2" steel to .501" or .502", see if the thread can pass throu.

to properly measure the minor dia of the muzzle device thread you need gauge pins.

 

[phylodog]

I took 30calmachinegunner up on his offer this afternoon and he got the threads squared away for me. Heck of a nice guy and I'm very thankful. The coyote crusher is assembled, hopefully she'll shoot well enough to get the job done. I'll find out once the Rocksett has time to set up.

 

[churchmouse]

I can see the process in my minds eye.

Knew it could be repaired.

 

[30calmachinegunner]

The muzzle break just needed a tap ran down it and was piece of cake, the barrel threads were another matter. I started out trying to use a die and it seemed like it was engaging the damaged threads okay but as it got closer to the "good" threads it just didn't feel right, I think the threads were damaged in a way(one side worse then the other) that it was wanting to cock.
I ended up setting it up in the lathe and picked up the old threads with the thread dial engaged and cleaned up the threads using a single point tool and just turned the chuck by hand. It didn't take much to get the threads to clean up but was a little tedious. I'm positive if just a die would have been used that the threads would have been unusable with a suppressor.

Just glad I was able to help, not sure which threads were causing the problems but I'm leaning toward the barrel, the muzzle break has been heat treated and it didn't give me any issues with the tap which it would have if the threads were undersized any. I'm guessing there might have been a little tool breakdown when cutting the barrel threads and it slipped through.

Everything ran true and concentric after cleaning things up.

 

[phylodog]

Update: I shipped the barrel back to Rainier Arms. I test fired it after 30CMG was gracious enough to help me straighten out the threads and it wasn't proving as precise as advertised. I contacted Rainier, gave them the whole story and asked if I could have it swapped or upgraded. The contacted me today and offered to ship a new match barrel or I could pay the difference and upgrade to an Ultramatch. I decided to upgrade and it is supposed to ship out today.

I wish it hadn't happened but how a company handles this type of thing separates the good from the bad in my opinion. I'll be spending more money at Rainier Arms in the future.

 

[1911ly]

+1 for Rainier Arms. So many company's just don't care. Let use know how the new barrel works.

 

[MikeDVB]

Glad to hear that about Ranier... Makes me feel better about the parts I have from them [even though I've had no issues].

 

[30calmachinegunner]

Well sorry to hear you had to end up sending the barrel back but glad they stood behind it. Just remember if it doesn't screw on by hand there's something wrong.