I'll admit, I've never been all that impressed with Starline in handguns, but it does work well enough. I recently got my first wildcat barrel, a 309 JDJ. I looked high and low, and the only 444 marlin brass I could find was Starline. According to JDJ, all you have to do is run 444 marlin brass into a 308 winchester sizing die. I've had nothing but problems. The cases either split or crinkle, or both. I've tried annealing, and it seems to kind of help, but this is brand new brass. It looks like guys who use Remington brass loose 1 in 100. I'm loosing 1 in 5 when annealed... and I haven't even fired them yet.
I've taken the the expander ball out of my die, lubing with imperial sizing wax, and adjusted so it just chambers. I have no other rifle dies between 44 and 30. Would a handgun die of say 41 magnum help? Or should I just cut my losses, and locate some Remington brass. This Starline brass wasn't cheap. Something like $75 for 100.