Pretty boring stuff now, but I include it for continuity...
(12) Drilling out sight base blank.
(13) Tapping sight base blank to 1/2" x 28tpi.
(14) Threading muzzle tip to 1/2" x 28tpi. Bevel linking barrel taper to rear sight base is also cut (10º).
(15) Completed thread.
Next up is torquing the barrel down, machining a locating flat on the barrel, and machining the front sight base & band.
(16) Front sight base blank fitted to muzzle thread.
(17) Barrel has been torqued into receiver; flat milled on top of rear sight hood.
(18) Spirit method of indexing the barrel to the receiver using the milled flat.
(19) Flat is now milled on top of leveled front sight blank. This is how I'll level the front sight with the receiver.
(20) Front sight blank has been trimmed on the bandsaw and mounted on an old M16 barrel stub. Beginning to mill it round.
(21) A look at the somewhat clumsy setup. What a PITA! Cranking the indexing head ~270º every .040". And I got the crank in an awkward position...
(22) Close-up of the first couple of revolutions, milling the muzzle relief.
(23) Completed the circular cutting; now to mill the sight base.
(24) Switched from a short 1/4" 4-flute end mill to a long one. Base/band came out pretty nice.
(25) Close-up of last cut.
(26) Close-up of base/band installed [loosely].
Side view of how it might look...If I don't screw it up...