Tula ammo has some inconsistencies with the seating of the primer depth. Firing pins that are somewhat short can have issues with the ones that are set deeper. I changed the firing pin out in my Mini 30 to one measuring .042 and it now shoots steel cased and Russian ammo without fail. You’ll hear people say the berdan primers are harder, maybe some but the issue could be with your firing pin being a touch short for that ammo.
