I just wanted to cover pinning a barrel to make a 16” over all length when using a 14.5 or shorter barrel.
I cut down a CHF barrel down to 14” and re threaded for 1/2x20.
I cut an 11degree target crown on the muzzle because… it was already in the lathe and apparently 11 degrees is the magic accuracy number.
I measured the fresh cut barrel and noted that I needed a 2.20” muzzle device for the proper length. I’m shooting for 16-2/16”
I wanted something a little different so I cut longitude for the brake ports.
Time to blue the part.
It was toughest to get the color close to the nitride barrel.
I made the pin to be .095 x.250.
Tig welding is the way to go. It makes the job quick with out possibly hurting the barrel.
Just a touch of bluing protect the surface.
Don’t forget to clock the muzzle device properly.
As for the upper receiver, you can lap the surface in. I made a quick lapping jig.
220 grit is the ticket.
Here you can see at the 1 o’clock position that the receiver will definitely be a productive service.
Clean out ALL lapping compound thoroughly. Use a little aeroshell on the barrel but, and put some loctite 620 on the barrel extension.
Try to clean all excess and torque the barrel nut. Hang the upper muzzle down and leave it over night.
Now you can re pin the upper and lower and enjoy!