hand drill bit recommendation?

Hey all,

I'm looking for a good 3/8" bit for limestone and granite.  I know at least a few of you guys have put bolts in by hand and I'm wondering if you could make a recommendation.

The bolts will be primarily for replacing anchors, but I might eventually put in a few routes on lead on limestone at least.

i bought a Petzl RocPec drill, so it accepts all SDS bits.

thanks,

-brett