Springfield XDM Slide question

Got a Springer Vortex optics base for my XDM 5.25 9.  Fits / works great...not crazy about the single mounting screw.  Spotted and drilled a second hole in the base.  Removed the base to spot the hole on the slide with a center drill...just barely left a mark...tried another CD, same result...wondering if those slides are quite hard, or if possibly just the surface might be...any insight appreciated from some who might have had experience machining the XDMs...fairly straight forward job and don`t want to bugger it...Thanks for any help...Jerry

It's a bit of an art but you can "spot anneal" the area by chucking an ordinary nail with the head cut off and spinning it on the area then allowing it to cool slowly, before drilling. But beware, it can be even trickier to tap the hole, and drilling all the way through can affect the action.

Why not try shooting it and see how it goes? Springer makes good stuff, I'd be surprised if it didn't hold up.

I haven't machined one, but it sounds pretty hard.  If you have to use a carbide drill to make the hole, tapping it is going to be a problem.

Thanks for the replies and insight...as I stated, it is a very nice mount and I have shot it with the optic mounted...they do make great stuff...have a local fellow who has worked on a whole bunch of them that gave me some help as well...thought he was off the grid but was able to contact him...Thanks again...