Well, I am no gunsmith but have don't it a "couple" times...
I have a couple dozen shotgun barrel cutoffs and practiced quite a bit before working up the nerve to do one. I have a 98 Mauser that I want to sporterize for the wife. But there receivers can be REALLY hard. I am hesitant to tackle that one. But the handis are soft and tap easily. If you have never done this, defiantly do a couple trial holes to get the knack.
Yes I use a drill press, I bought a fancy adjustable vice for it and that helps allot, but you could make do with a non adjustable model as long as its got a sturdy wide base. I level my table and check to be sure its square to the bit. Runout on my quill is pretty good so I don't have problems there.
Anyhow, now that everything is square, I clamp the barrel lug in the vice and recheck. Then I put the base on the barrel and mark holes and drill the hole and with out moving anything tap using the tip of the chuck as a center. Lots of cutting oil and I go slow, as I said I'm no professional.
Screws, taps and appropriate drills are available from Brownells and also Midway.
Good luck,
CW