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by Marlene
I would definitely not try drilling a bolt carrier without at least a drill press, if not a milling machine. Cobalt drill bit is the minimum and a straight flute carbide bit is a better choice. A cobalt tap did just fine, after a terrifying moment of almost breaking a high speed steel tap off in the hole.
After my first attempt to drill and tap, I would have bought a drilled carrier if that was a reasonably priced option. Since the SCR carrier is non-standard, I had to continue and figure it out.
If you want specific cutting tool recs by part number, let me know. I’m happy to share.