I opted to make them myself. Don’t have specific notes in front of me but from memory.

357 shot shells.

4.5gr 700x
2 shot cards cut from cereal box or similar weight cardboard.
90gr of shot
1 more card board disk
Wax dripped on top to level of case
Heavy crimp

I sharpened a 38 special case to cut the disks.

Very soft shooting ... fun to make.

If you need absolute recipe let me know and I’ll venture into the dungeon.