Interesting article, of course. It really shows off the 6.5's "stuff".

Don't know what the pressures were, but the little 57mm IMP chamber I played with some time ago, my daughter's .260 CLC (Carol's Little Ctg.)was a 6mm rem, or 7x57 necked to hold a 6.5 bullet, with the front end shape of a .260Rem. - short neck with the standard 20 degree shoulder.

The case held 60gr. of water, same as the 6.5x284, seems to me.

I was loading 52.0gr. RE#19 (not positive on that load) with a 120gr. Barnes XLC and getting 3,308fps, using 30gr. LESS powder than my M70A .264Win Mag and of course, a mere 50fps short of the magnum.

That is likely a good load for long range goat/sheep-like critters, too.