Will be getting my rifle back soon. It was built on a 7x57 small firing pin receiver. I'm wanting to shoot my 405 jacketed bullets to start.

Well lets see.

7x57 max pressure = 3900 bar
Base area = 1,084 cm2
Block thrust = 3596kg

45-70 base area = 1,86 cm2
So max pressure = 1933 bar

Thats 28036 psi for the metric impared.

quote:

Originally posted by The Dane:
Well lets see.

7x57 max pressure = 3900 bar
Base area = 1,084 cm2
Block thrust = 3596kg

45-70 base area = 1,86 cm2
So max pressure = 1933 bar

Thats 28036 psi for the metric impared.

What's really funny is that we would write it as 28,036 PSI.

That rolling block was not made for what we call the modern 7x57; it was a Spanish version which was different. 3900 bar is about 56000 PSI, and the old 7x57 was far below that. Put that load into a 93 Spanish Mauser or a 1902 rolling block and it won't last long. So any comparison is not necessarily valid, except in this case it is by accident.
However, the action is very strong and shooting it at the SAAMI spec of 28K psi, is fine.
Having said that, the only correct propellant for a vintage 45-70 it is real Black Powder and lead bullets. Anything else doe not feel the same.