Welcome aboard. I also echo what Dan said. I read an article on the .308 Marlin Express in the new G&A and one of the points they made attributing to the gain in performance of the line of leverevolution ammunition is the powder. It is a proprietary propellant that burns relatively slowly but keeps pressures moving up through the length of the barrel. Like a steady PUSH, rather than a kick in the butt. At least 20" seems to be the minimum with 24" optimal. The only way to gain in a 10" is with a quicker burn. Try
www.reedsammo.com if you want loaded ammo taylored for handguns. If it is not listed on the website, shoot Ron an e-mail, they can do most anything and at a very competitive price. Just tell him what you are using, 10" T/C, and go from there.