There is also a 30BR that is winning matches may want to try www.benchrest.com
and get on their forum and ask those guys and when your on that site on the cover page is a listing of ads pull up the bullets section and go over to BIB bullets and get Randy' number and give him a call he is the guy who got the bullets going for the 30BR. The Dasher case is off the BR. Don't get me wrong when I say this the 7br is a great Silhouette round. What is making the 30br is 1/18 twist barrels and 112/118gr bullets you got twist to match bullets that is lacking for the 7br case as a rifle. You have light bullets but not the twist if you start with a 100gr bullet in the 7br the top velocity is around 2400fps for every 10gr increase in bullet weight you drop 100fps of velocity going to a 20" barrel may give an increase over the pistol load appr 100fps. You can take a 150 gr cast bullet in a 7x57 or 7-08 with the same amount of powder as the 7br and get 500fps better velocity. Rem made the 22 and 6br in the custom shop and those few 7br rifles like mine. I had pretty good luck with the 130gr 7mm pistol bullet it was set up for the lower velocity. Well good luck.