Bosch 18v rotary drill on hard rock (granite, basalt, metamorphic etc.)

Looking for a nice compact drill, that doesn't cost an arm and a leg, but could still work on hard rock. I am in Washington so everything is mostly hard rock. Anyone have any experience on this? Any other suggestions? The Bosch 18v seems pretty sweet... Thanks! 

Works well for me!  The really hard rock, eg. Ibex UT, will take more batteries as well as bits, but this drill will do the work.  I went from a 36v Bosch and believe the weight savings out weighs the any disadvantages of the 18v.

Roy - Great to hear it works well there. Weight is definitely a nice thing to cut down on, especially with all the great technology. Thanks for the info! 

I have the lighter Bosch 18v hammer drill (rhs181bl).  It works well on Tahoe granite and is very lightweight; I got it for $200 (bare tool).  It isn't heavy duty and needs a break if you are drilling a lot of holes.  The 6ah battery lasts a long time (but is pricy).  The downside... it's not heavy duty and not what a heavy bolter would want, but works for me for the occasional route or bolt/anchor replacement.  Most people will steer you to the heavier 18v version (GBH18V-20K21), which is what I would want if I'm going to be drilling on a regular basis.  A buddy of mine went with the Dewalt drill instead because it delivered a few more joules of force (it's a little heavier)

Eric - I am not a heavy duty bolter... yet. I figure the 18v will get red hot if you go at it for awhile, but I am patient enough. It sounds like for replacing or for small route development it is probably going to be enough. Thanks! 

Lots of these drills come in different sizes. Any "1 inch" drill ought to do. 

I use a Bosch 18v with a 6amp hour battery and can get easily over 15  3/8"x3" holes.  In fact the last time I used it I drilled 18 holes and still had two lights out of three on the battery life indicator.  The battery that comes with it I think is a 3amp hour and is still capable of 10-15 holes.  I think the key is letting it rest between holes.

I have put up several routes with it and it has put up with loads of abuse.  When bolting on lead I leave it on a long leash and use a fifi hook to leave it on the last bolt drilled and the drag it up the rock using the one hand and teeth method.