Re: .300 RUM brass
Thanks for the data! Looking at it, I think it will compare very favorably with H870. Here's some H870 data I have for those bullet weights:
180 Scirocco, 114 grains, 3265.
180 XLC, 114 grains, 3233.
I have "Cold Batch of H870" written in my notes for those loads. I stopped because of difficulty stuffing more powder in--not because of pressure.
200 AccuBond, 112 grains, 3246 ("Normal" batch of H870).
With that bullet I did run into a pressure sign once I got over 3300 fps. 112 grains was pretty mild but it easily beat my Retumbo load by 50 fps. Unfortunately I found accuracy to be poor with it. Looking back I now believe I was compressing the powder enough to cause seating depth variation and that's probably where the accuracy problem came from. I think I could have overcome it with more careful filling procedures but I was happy enough with the Retumbo load I didn't bother trying.
But that's great. Given the velocities you're getting with 180's, I don't think there's any way this powder will end up being "too slow" for bullets 200+ (as I decided H870 was for 180's and under). I think it's really going to rock with 240's!
Mine's in the mail. I'll let you all know how it does just as soon as I can try it.