480 Ruger Load Development

[james]

I loaded and shot some 416gr cast on top of accurate 11FS. I started in middle of published load data because my OAL is so much longer than published and at that, I was still below even the starting charge published velocity. My cases were sooty all way back to rims, recoil was light and firing pin strikes looked puny compared to another mid range load I’d developed.

Western manual data says (same case as I’m using):
410gr 18.8gr 1,136 to 22.1gr 1,276 41,398psi 1.635″coal

My OAL was 1.753″, charge I tried was 20.5gr for 1,080.

I’m looking to get to 1,200. Question is, for those loading similar cases or using this powder, would 0.5gr be too much of a step to move up and try?

[Jicand]

Everything you said points to underpowered loads. A .5 step up should be fine. I would do .5 steps up to max loads and fine tune after finding the best of those charges. Just keep an eye out for pressure signs during the work up

[fatguywithagun]

Case volume makes a HUGE difference in pressure, moreso than a lot of people assume. So if your OAL is that much longer than published, that’s probably the culprit. Why are you seating so long?