I recently started going climbing (bouldering only) and love it. I've been maybe twenty times now and have made a LOT of progress.

I'm a guy and my strongest muscles are back, biceps, etc. which makes campusing really easy for me. As long as I have a good grip, I can pretty much pull-up my way through a route.

What really kills me is my grip. When I try to do routes with smaller holds, slopers, pinches, etc. I get tired out very quickly. What's worse, while I can keep on doing campus routes for a long time, just a couple attempts at routes with tough pinch-holds will kill my forearms.

After that, I'm basically done climbing unless I spend the rest of my time at the pullup bar.

My endurance has definitely improved, but it's still nowhere near my back / shoulder strength, and I really would like it to be so I could spend more time on those types of routes.

What are some good exercises I could do to target my grip / forearms... or is it just a matter of time / practice?