I saved the issue of Guns & Ammo with the .40 G&A creation/test review - It was a converted Browning Hi Power RCBS made up the dies
Bar Sto made a barrel, but the cases were based on the .224 Weatherbuy belted magnum rifle case. With the RCBS dies you also got
a reamer to thing the inside of the rifle case. Headspace was on the
blet of the case. They used the 180 gr. JSP Remington bullet offered for the .38-40. I think the performanc e was that 180 gr. bullet at a bit over 1,000 fps.

the .40 G&A was doomed because of the cost of the weatherby brass and case prep. I wouldn't say the .40 G&A evolved into the 10mm AUto
or .40 S&W but it inspired a more practical .40 cal cartridge design.

my $.02

Randall