In my rossi 92, and later my winchester 73, both in 45 lc, I just filled the case to the top, and seated the 250 gr bullet, compressing the powder about 3/16". Powder was goex, first 2f, later cowboy. Bullet was my cast, Lyman mold made for the old colt revolvers, has good sized grooves, lubed with my BP lube. Load was plenty accurate out of those and my revolvers shot out as far as maybe 50 yds, never tried further. The charge worked out to about 37-38 grs. I wanted as close as possible to the original 1873 load of a 255 gr bullet over 40 gr of 2f.
I did load 158gr re grooved bullets in 357, but I don't remember the powder charge, and they were only fired in revolvers. The case was full, they were accurate in the revolvers, but it was for my wife, she just used my rifle.
I made a custom groover, to open up the lube grooves. Used it on regular cast bullets.
Now, the 58 Berdan rounds were poured through a drop tube and pre compressed.
Shotgun, just "square load" it, equal volume powder and shot. You can use modern plastic shot cups, but they will leave stringers of plastic in the bore. I just used fiber wads. In 12 GA, using regular 2 3/4" plastic shells, it came out to 65 gr of 2f over 1 1/8 Oz of shot, with an over powder disc and one fiber wad, and the shell crimped.