As far as lead build up is concerned, if you are shooting FMJ or jacketed ammo, don't worry about it. If you are shooting unjacketed lead bullets, you should use a bore brush when you clean. This will help. Every few hundred rounds maybe use a cleaner that includes a lead remover like Shooter's Choice Lead Remover. After many rounds the grooves inside the barrel may look like they are becoming shallower. That is likely lead build up. You would then need to get a more aggressive product like Lewis Lead Remover. Both the products I mentioned are available at Brownell's.
Jim's Rules of Carry: 1. Any gun is better than no gun. 2. A gun that is reliable is better than a gun that is not. 3. A hole in the right place is better than a hole in the wrong place. 4. A bigger hole is a better hole.