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Barnacle Brad · March 12, 2009, 02:45 PM

Springfield 45-70 Trapdoor Cartridge.

I am new at reloading BP Subs and did a test to find how full a case is when using a drop tube versus straight from the powder measure (RCBS). The result is that the case containing the charge from the drop tube is maybe .25 lower in the case than the other (to be expected).

My question is about compression. For the 60gr charge specified in the Hodgdon manual a compression of .100 is noted. So when does powder compression begin for unsettled powder thrown from a powder measure? Is it when the bullet/wad touches the powder, or when it reaches the level of the settled powder as from the drop tube?

On another note, what is the best primer to use for the triple seven/45-70 trapdoor?

So many questions - so little time...

March 12, 2009, 02:45 PM	#1
Barnacle Brad Senior Member Join Date: March 12, 2009 Location: Greybull, Wyoming Posts: 416	Advise for BP Sub (777) Volume Measure Springfield 45-70 Trapdoor Cartridge. I am new at reloading BP Subs and did a test to find how full a case is when using a drop tube versus straight from the powder measure (RCBS). The result is that the case containing the charge from the drop tube is maybe .25 lower in the case than the other (to be expected). My question is about compression. For the 60gr charge specified in the Hodgdon manual a compression of .100 is noted. So when does powder compression begin for unsettled powder thrown from a powder measure? Is it when the bullet/wad touches the powder, or when it reaches the level of the settled powder as from the drop tube? On another note, what is the best primer to use for the triple seven/45-70 trapdoor? So many questions - so little time... __________________ Brad