I imagine if you wanted to make this, a regular HSS bit wouldn't be enough to cut through if it's properly hardened steel. Which is actually pretty likely, I've had trouble drilling through a horrible freight caliper. Probably the easiest thing would be EDM if you have access to such a machine.

Short of trying to do something like that, it would probably just be easier to grind down the outside of the top jaw some to bring the tip back, to make it parallel when marking like the image with the green check mark. Also probably lightly smooth the edges on the inside of the slide jaw so it doesn't scrape against the work as much.

Guess that's another small project on my list lol.