The reputation for a killingness of a cartridge is really down to heresay, and I would opine is really down to the early users, their choice of bullet, shot placement, range and intended target.
So go back in history to the 280 Ross. A canadian cartridge designed by a Scottish Nobleman. It was a 7mm firing a 140 or 156gn bullet at above 3,000 fps. It was offered in solid spitzer type bullets for military use, a bronze capped soft point (think ballistic tip but use bronze instead of plastic) and I believe it was adopted by the Canadian military in a straight pull rifle. This did very well on the target range, not so well in the trenches of WW1.
It was popular for a while either side of WW1 for plains game isn east africa. Gained a reputation for being accurate and killing very well. That is until a certain Grey decided it was the perfect to use on Lion after chasing them on horseback. It wasn’t. The bullet was too soft for close range use, bullet only wounded a lion, that turned round and mauled Mr Grey. He did survive, but not for long.
The 280 Ross is but a footnote in history, although it has pretty much the identical ballistics of the 280 Remington, 7mm Rem mag, 7mm PRC etc.
Meanwhile a certain other Scottish gentleman by the name of Bell was making an outstanding reputation for the both 7x57 or 275 Rigby, and the 6.5 Mannlicher by using solid round nosed bullets for shooting several hundred elephants with brain shots. Same cartridge in the hands of the Boers and the Spanish had taught the Brits and Americans a thing or two about modern cartridges and marksmanship. Whilst not popular the 7x57 is still going strong, the 6.5 Mannlicher less so, but it’s cousin the 6.5x55 is still very widespread especially in Scandinaviour.
And the more recent 6.5 CM, 7-08, 7 PRC bring these right up to date and allow manufacturers to load a full power without worry of them being used in very old rifles. I suspect, given the adoption of the 277 Fury as a military cartridge in the US, we will see this becoming all the rage in the next few years.