Then you'll probably appreciate this pic of the neatest internals I've seen on a push-rod fore-end with ejectors:

Daryl:
These fairly light game guns were likely proved for a service load of 3 to 3 1/4 tons, which is 6,700 to 7,300 psi by straight conversion.
8,000 psi might be a little harsh on the Jeffery, but I'll do some research and come up with something I'm comfortable with.

If I get to the range this weekend I'll use my low pressure bismuth loads rather than the Remington Nitro-Steel that the cylinder-bore Greener Empire happily digests!