MP 454640 load data?

[pdgoutdoors]

My freshly cast and PC'd Penta HP boolits from the MP 454640 are weighing in right at 261-262 gn. This is my first time loading with this boolit. I'm stuck on if I should start out with the published data for a 250gr LRNFP or the 270SAA, as my Lyman cast handbook does not have any data for a 260gr projectile.

If anyone feels comfertable, I would love to hear what load you have success with for this Boolit with the Penta HP and what OAL you are seating to.

[farmbif]

what cartridge are you loading these into? I use this bullet exclusively in 45 colt chambered Rossi 92 with 20 grains 4227. I use same load regardless of which hollow point or solid pin used when casting, lube sized at .454 with carnauba red. crimped in the crimp groove. never even measured OAL. just load and shoot, pick up brass, rinse and repeat.

[pdgoutdoors]

I'm loading them for a SAA and Marlin 94 both 45 colts. Sorry I should have specified that.

[farmbif]

I get right at 1200 fps out of the Rossi, probably not a load you would want to use in an antique handgun.

[justindad]

Consider the case capacity remaining after the boolit is seated. Compare that to the 250 & 270 grain. You can create separate threads here with the name of the boolit in the title and ask folks for the boolit length. Or, look here: https://bulletmatch.com/
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If you’ve never done this before, share your plans here for folks to review before you actually assemble the rounds.

[Minerat]

I use 6.0 gr Red Dot for a 260 gr RCBS non hp 45-250 I get 700 fps from a Ruger Vaquero.

[Iwsbull]

Measure them from the crimp groove to base and the MP 640 and the 270saa are very similar.