Buffalo Bore low pressure “Black Powder Equivalent” 45-70 loads are safe to use in “Trap Door” actions, assuming the action is in normal operating condition. Original (1873) 45-70 Govt. ammo was released to the military, in the military rifle of the day, which was the Springfield model 1873. SAAMI has set 45-70 pressure levels at 28,000 PSI, which is potentially enough pressure to damage trap door actions, depending on the pressure curve of the ammo. Most authorities believe that 18,000 to 20,000 PSI is safe for all trap door actions that are in normal operating condition. These loads are operating at or below 18,000 PSI.