re: .242 Express claimed velocity of 3000'/sec.

The shown 3000'/sec is contradicted by other sources (that I cannot find at the moment), suffice to say that some sources put muzzle velocity at 2800'/sec.
Either way the test barrels were commonly 28" or 30" long.
- Speeds out of usual sporting riflel 24" barrels would be commensurately lower.
- My own Cogswell & Harrison Mauser .242 Express with 24" barrel will safely get 2750'/sec with IMR 4350 and 100 grain bullets. IMR 4350 is arguably very close to the Nobel No.1 or No.0 powders of the day that the cartridge was likely loaded with in the mid 1920's.

I highly suspect the 3000'/sec claim was nothing more than advertising hype.

Just my 2¢ worth.
- Mike