After measure Ogive, I made a dummy bullet (no powder, primer) and noticed the starline brass would not fit the chamber. These cases were used in my springfield trapdoor and I fixed the issue by doing a resizing full body length, then they fit the Sharps chamber fine!
After primering and belling the mouths, I proceded in making 20 test loads.
65 gr (*by volume, then trickle by weight) Old Enysford 2F black powder
.030 greased veggie wad
Compressed with a Montana Compression die .090
520 gr BACO "Money Bullet" compressed the load further by .100
Taper crimped ever so slightly to eliminate the bell (so they would fit the chamber)
Wiped their butts and chambered each load to insure they *fit*

Background:
A 2 year wait for this custom build as I ordered it when I retired in 2018. Picked it up a week ago from Tuesday.

I cast my own 520 gr bullets using a BACO "Money Bullet" mold. 20/1 lead.

Caliber: 45/70
Barrel: 30" heavy Octagonal
Wood: Semi-fancy Walnut
Buttplate: Traditional Steel
Metal Finish: Pack hardened
Brass Escutcheons
Fireblued polish screws
Custom bedding
Custom long range sightsby Steve Baldwin: rear Vernier Tang and bubble-leveled globe front with interchangeable silhouette patterns.

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