Fire Forming 100+ 45/70 for Two Rifles, Your thoughts?

[country gent]

With the right sized wads and compression of the black powder bullets can be hand seated the bullet cant seat deeper its supported by the powder wad column, Powder cant spill since the snug fitting wad and compression are holding it in place. My bpcr ammo is hand seated bullets and only the lightest of tension after seated. Bullet still spins in case and can be pulled by hand. I have had them come out handling and with the compression and wads no spilled powder.

As RFD stated with PP bore riding bullets most dies don't size the neck down enough even for this type of fit. Most bore riding PP are wrapped to a dia of .448-.450 and most dies are set up to size down to around .455-.456 inside dia of the mouth. Here is where a bushing die is handy.

[MostlyLeverGuns]

I usually take these steps with a batch of new cases. Uniform primer pockets, deburr flashholes, partially size to insure necks are round, neck expand with step/M die and load, load and shoot at shorter ranges, 200 yards or less. After the first firing, 'neck size', measure case lengths, trim all cases to the length of the shortest, anneal case necks, chamfer and deburr case mouth. Weigh the cases and separate into case weight ranges, weight range is your call. Expand necks and load. Keep cases separated for the different rifles.