Barrel rail for revolvers

[Velocity Villan]

Dr Stan, were you an MR in the Navy? Noticed the insignia.  I was an MR.

[Dr Stan]

Yes I was.  August 17, 1973 to August 16, 1977.  Discharged as a MR2.  Two WESTPAC's one on the USS Coral Sea CVA-43 and the 2nd on the USS Samuel Gompers AD-37.

[Roadracer_Al]

Since you're already working on the mill, you could cut the barrel to a D shape using a rotary table & tail stock, then cut the rail in the straight leg of the D.