Wes wrote:
Are you putting both scope mounts and iron sights on it? If so the front
dove tail would need support.

Dad uses a scope. Eyes aren't good enough for iron.

In this case, the barrel was straight (thank God!) It's a match barrel,
and it loves the hell out of Yellow Jackets from Remington. Sorta odd,
YJs are not IMHO the classical match ammo in any stretch of the
imagination.

Dad simply turned the action 180 and reclamped it to the angle plate to
mill out the dovetail for the forearm hanger.

I had to think for a while to imagine how a tapered barrel lies in a vee
block. My brain told me a line of contact on both side but until I took
tapered line up punch and vee block to verify, I wasn't ready to bet myself
money on it.

The end of a tapered barrel will touch the sides of a V block at three
points at the most, depending on whether the block is square to the
table or on a angle plate. On an angle plate, the barrel will touch at
each side of the v, along the circumference of the barrel, and at a
point on the lower front edge of the muzzle (not exactly, but this is
machining, not rocket science).

Can you support the action in the mill vise and then clamp your vee block to
an angle plate at the barrel end?

Sure, you could, but how is one to determine if the bore is parallel to
the table?