New to site-got a 40xbbr 6mmbr with 1-12 twist-want to use 80 gr. match bergers to start. Bought a bunch of live 77gr. lapau's which shot prettty well. It is broke in and got fire formed brass. Can you help with a powder to start with. I am hearing v133 or varget. I know there is more work to go,but a suggestion of type of powder would help. Thanks Jim