.45/70 cast bullet loads

[OSOK]

I have some 450 gr. cast bullets to load in my BC. Unfortunately, I can find very little info on that weight bullet. I am open to powder suggestions, as I haven't bought any yet. These bullets are fairly soft, so I am looking for trapdoor level loads.
Thanks ahead of time to all the experts on here.
Les

[quickdtoo]

Just use 500gr data which is plentiful.  The Lee manual lists 475gr data for 3 powders.

XMR2495 40.5gr start 45gr max 1565fps 16kpsi

XMR4350  same data  1258fps 16.1kpsi

XMR3100 44.1gr start 49gr max 1221fps 16.3kpsi

Accurate has data for the 460 Cast Performace gas checked that may work ok, their standard rifle loads are actually trapdoor loads by SAAMI standards with a max pressure of 28kpsi.

http://www.accuratepowder.com/data/Acc%20Guide%20v3.3%20version.pdf

Tim

[OSOK]

Thanks Tim!

[ruppster]

You can always try TrailBoss powder, I like it for trapdoor/low power 350gr cast 45/70 loads. Here's IMR's recommendations. http://www.imrpowder.com/PDF/Trail-Boss-data.pdf

[manatee1947]

I have historically used IMR 4198 or RL7, but I have just picked up some XMP5744, and some SR-4759, both are highly recommended for reduced loads. In fact, the accuracy load for a 500gr bullet is listed as 26.5 gr of xmp5744 for 1253 fps. Any of the above would work well.
The latter two are more bulky so would have greater load density. I used the 4759 years ago with good effect.

[Big Blue]

I have had very good accuracy from 460gr. Cast Performance Bullet over 38.0gr. of RL-7. The 460 gr. CPB has a gas check. My two favorite powders for the 45/70 are RL-7 and IMR 3031.
Don