Home Forums Hunting & Shooting AR and Tactical Rifles Tac 20 build (pic heavy)

Another update - barrel profiling and installing the barrel extension.

I didn't take many pictures of barrel profiling, was too busy dodging chips. (just turning the blank down from 1.25" to 1" makes a lot of chips, then profiling started from there.) I kept the profile simple - 1" at the shank, .875" to the gas block, .750" at the gas block and .746" to the muzzle. I may add some flats or fluting later, but not at this point.
Note the different chips piled up - piles of golden bronze C and 6 shapes from roughing with heavy cuts, and then fine curly silver hair from the finishing cuts.


Piles of this stuff everywhere, including my pockets, hair, and they stick in your shoes. I had to clean the floor after every pass down the barrel. The gold/bronze color is from heat; if we were pushing a little harder the chips would be blue and purple.


A bit of polishing with emery cloth and then Simichrome on a paper towel cleaned up the barrel to a nice shine. (I don't use shop rags on the lathe, but paper towel can just rip if it gets caught instead of winding up your fingers/hand/etc.)
BTW that ugly chunk of cardboard back there was to keep chips and cutting oil off of the wall, but it fell down during my project and I didn't bother to fix it.


No pics of contouring or polishing the front end of the barrel, so on to crowning the muzzle. I cut an 11° target crown on this one and finished the OD with a small chamfer.


A little polishing, and the crown is done (sorry for the fuzzy pic):