Finally getting some of this down,

One of the tests this time was trying the same load with different primers, since I was finally able to get some Federal Magnum to try. 
So, 500-grain Lee bullet cast of 20-1 alloy(first try with it) over 35.0 of Blackhorn 209, ignited by a Federal primer.

Same load with CCI primer

Both in Winchester cases prepped as they would be for black powder loads.

Maybe the Federal Match primers would make a difference, but with these(I shot two groups of each) I'm not seeing any.

And, once again, a little black: 68.0 grains, the 500-grain bullet cast of mongrel alloy*, in a Starline case black powder-prepped, CCI primer

Yeah, that's three damn near in the same hole.  This is a fairly hard alloy, and it seems this rifle/cartridge likes that better than soft.  In comparison, with the bullet 25-1 and a Federal primer,

The vertical is quite likely me; the day was getting hot and I was getting a bit off by this point.  And yes, I know, I should've had this load with the same bullet as the other; I'll do that in the next test batch.

I did fire some with the Lee 405-grain bullet and Blackhorn; not worth showing.  I'll need to mess with things a bit on that, which'll include trying it paper-patched with the Blackhorn powder.

The 330-grain hollowpoint, mixed results.  These were in resized Starline cases over 44.8 of Blackhorn, both with CCI primers(loaded before I had the Federal); first one

 not bad at all, the second

strung a LOT vertically and a bit horizontally; I think I'm going to have to blame myself for at least some of that.  I'll need to try these again with both primers.  Also, these do NOT like being loaded(with Blackhorn at least) in black-prepped cases.

So.  I'm going to try the black powder loads again, both with the 500-grain and the 405- grain(which had some interesting results last time), and try the 340 with Federal primers and Blackhorn.  And since the rifle seems to like the higher tin bullets best, I need to figure out just how much tin to add to the 30-1 and 25-1 lead to bring it to 20-1.  And since I read somewhere that the original alloy the US Army used in .45-70 was 16-1, ought to make some of that to try.

*Range lead, so no idea of the mix