Thanks eerw!
How big of a file should I use? Is there a groove in the old site to use as a guide/guestament
There's always more than one way to skin a cat...
I just tap the front sight in all the way and drill through the bottom of the front sight using the existing holes in the slide as a guide on my drill press. Not sure exactly which bit I use, but I've done this several times now and it makes short work of the job.
Good luck,

I actually do that with my cordless drill..makes the job about 5 minutes..
my old gunsmith friend just shakes his head..
the couple of times I did it with a file..I installed in the slide, marked both sides with a punch, put in a vise and use a small diamond file.