Took this trapdoor back to the range tonight...with 20 rounds of 0.458, 500gr round nose, 20-1 alloy form buffaloarms.com. Here is tonights data.
45-70-500
Historical target (Wolfe's book): 1315 FPS, minimum acceptable 1270
My results:
500gr, 20-1 soft cast over 39gr. IMR4064
MV average: 1305
Min: 1262, Max 1339
SD 17.8

Took some cross-referencing between all my manuals to make this starting point. I'd say I darn near duplicated the original target!

At 100yds, I put 4 out of 5 of these rounds within 2 inches of each other. I messed up the third shot and it flew 2 in. right of the group. My group impacted 12 inches above my point of aim, and 3 inches right. The M1879 sight was set all the way down. I double checked my front sight post and it is a perfect 0.100 above it's base...exactly what it is supposed to be. This load was very fun to shoot. Next trip I need to make sure my tape measure is in the bag so I can paste my "aiming" target in the exact spot needed to get me all over the bull.

Maybe a third of my cases are showing pierced primers, the rest are fine. Instead of shelling out hundreds on the thicker skinned primers or magnum primers, I may purchase another firing pin and adjust it's max protrusion. They can be had ~$20.

EDIT: Track of the wolf has the LEE M1873, 405gr hollow base mould back in stock. I got me one. I have no pot, no lead...but I have a mould now!
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