There was a young fellow who used to come to my place and hunt elk. He used a 7mm-08 (I know. It's not a 7x57 but, headstamp aside, it works just the same), He killed three bulls with one shot each (he used 150 partitions). He was convinced he needed more gun, after a close encounter with a grizzly, so he bought a 300 mag. That year, he shot another bull. It took one shot, just like the 7mm. He said the main difference, from what he could see, was that the 300 weighed another pound and a half and it kicked a lot harder.
I have built a couple 275 Rigby's; one on a Norwegian Krag. They worked a lot like 7x57's too GD
