GP100 scope mount

I picked up a ruger GP100 today (1st Ruger) and had asked the sales person if they make a scope mount for the GP100 and he said yes but, the gun had to be drilled and tapped. I asked their gunsmith what that would run me and he said a hundred dollars or so. I just spent 489.00 for the gun and really don't want to have to dish out another 100 dollars right now. Is there a scope mount made for the GP100 that I can put on myself? Thanks for any help that anyone can provide on this subject.

If your GP100 has a 6-inch barrel, then yes, there's at least one do-it-yourself option I've seen (there may be more):

http://www.jackweigand.com/Ruger-GP1...-No-Drill.html

The pictured one is on a Redhwak, not a GP100, but it works the same way.

Thanks for the information, i'm gonna check it out now.