I read with interest the comments about the 3.5mm carbide drills for sale of EBay. (Thank you Speerchucker30x378)

If I might ask about other specific applications, what is the consensus for an optimal drill material to be used for drilling and tapping an Anschutz receiver? These have a reputation for "hardness" (is that a word?) that seems (from what I read) to be difficult to overcome.

Any input is appreciated.

I've drilled and tapped quite a few of the Anschutz rifles over the years. I don't recall them being overly hard. I should think that any HSS drills should work fine in them. I have taken to drilling everything in the smaller sizes with carbide now days, but only because it has become as cheap and readily available as HSS. Carbide is also easier to sharpen in my drill sharpening machines and doesn't plug the diamond wheels like steel does.