Best tap for scope block screws

[Kurt]

I use three taps, One taper to get a good straight start and finish it with a plug and bottom tap. I like the high Carbon taps.
The drill bit is a #31 (.120") MSC or you can most likely get a good one at ACE. or maybe Harbor Freight, but I would try Ace first.
The 6-48 is very small tap and they can break very easy...... I would not get a carbide for this job.

Kurt