1873 Speingfield Trapdoor 350g Lead Cast Bullet Loads

[SRE]

Anyone have any 45-70 trapdoor load data for the 350g Lead Cast bullet using H4831 or H4895? Ran into a decent amount of this powder as well as the bullets coincidentally. Thx in advance!

 

[Jim Watson]

I don't have any data, I don't load BPCRs with smokeless, but H4895 is said to be a decent .45-70 powder.
H4831 is very slow and an "off label application" in .45-70, but Ken Waters liked it; said it was nearly as dirty as black but gave good accuracy. If you could find his Pet Loads article, there is some guidance there.

 

[chiefr]

I shoot trapdoors BP only. I never could get reasonable accuracy with bullets less than 400 grains.
Soft lead and BP are all I will use in my trapdoors.

 

[Dragonflydf]

I use 405gr cast round nose on top of a case full of Triple 7 FFG, I figure out where the base of the seated bullet would be and fill it to that point, I don't like using a compressed load. For me, shooting smokeless in a trapdoor is bad ju-ju.
That rifle is 142 year old, I would hate to see it not make to 143 because you had to use smokeless powder.