Slug the barrel as said above. If the barrel is .451, then

by Murphy , Sunday, April 22, 2012, 20:46 (4598 days ago) @ Cherokee

I agree with the others. Typically you want to go .001 thosandths over jacketed diameter with a cast bullet.

Lube's are another thing. The array of bullet lubes available both store bought and home brew are plentiful.

You may or may not have heard of this site http://castboolits.gunloads.com/

While there are some fine folks here with a lot of knowledge, you'll find more on the above site than anywhere. I've been a member there for 5-6 years now. I learned more in the 18 months I was on that site than I'd learned on my own in the prior 25 years.

Good luck and welcome to the 'Brotherhood Of The Silver Stream'.

Murphy