For barrel pins, I've used both the Dave Rase drill guide, and a milling machine/drill press vise.
If you have a drill press, a good vise will be very handy. Most drill press vises have shallow jaws. Milling vises oft have a deeper jaw. Mine are 1 3/4" deep x 6" wide, I would guess a minimum jaw would be 1 1/4 tall. This is good for drilling thru barrel lugs and thimble pins. Or, use Dave Rase's drill guide.
Now, if you had a Dave Rase guide that had body and tap drill bushings, you could do lock bolts and tang screws.
For tang and lock bolts, I use a drill press, with a table-mounted point centered directly under the drill spindle. I make a center punch mark on the barrel tang and the trigger plate, set the gun on the point, and using a tap size drill, drill down thru the tang toward the trigger plate. Flip the gun over, set on the center, and drill thru from the trigger plate toward the tang. The holes meet in the middle somewhere. Then drill from tang toward trigger plate with a BODY size drill. Stop before you hit the trigger plate. Run a tap down thru, by hand, please, until it exits the trigger plate.
