Meister makes great bullets and charges for it.
I find mastercastbullets.com and Penn Bullets to be as good and less expensive.
Call and talk to the company about the size bullets you need and how to determine this or place a SMALL order (generally, 100 but ask if you can get a smaller sample). If you get leading, tell them WHERE in the barrel and they can help you determine if you need a larger diameter or softer alloy (most commercial bullets are already too hard and I have NEVER needed a smaller bullet).