Not really. The loads I am trying right now for my Rem 300 suam with IMR 4350, 165gr Scirocco II, Rem 91/2 M primers ispretty close tothe case mouth.Don't rememberexactly all the loads I have loaded without going and checking thembut they are all straight out the Lyman 48 Edition for the 165gr Scirocco with IMR 4350 powder. It is actually a compressed load and I can hear the powder crunch just a little bit everytime I seat the bullet.