Swing back to "high velocity cartridges, the following is a nice articel about the 280 Ross: https://gunsmagazine.com/ammo/the-280-ross/

Fjrdoc, your 1910 Ross sounds like a great rifle with the intergral peep sight. The 1910 commercial Ross was a great, well made gun. (Interesting that the rage in Europe seems to be for straight pull rifles.)

I shot my 280 Ross with some 0.287" bullets which I believe is the correct diameter though some people reported good accuracy with the standard 0.284" bullets.

John, you questioned the high velocity craze. From what I read, in the early 1900s, there were reports of outdoorsmen killing dangerous game with light, small diameter bullets fired at 3000fps. I believe Roy Chapman Andrews killed one or two tigers with an 1899 Savage in 22 IMP (22HP). I thinh Bell liked that cartridge.

Elmer Keith questioned the HV craze did some experimenting with 22 cal bullets, machined out of brass rods. (I guess one of teh first mono bullets).

The ballistics of the 280 Ross really matches that of the 7mm Remington maginum. With today's mono bullets, perhaps Mr. Grey would have killed the lion (standing there, shooting like a man.)