Jck O'Connor was one of the first gun writers to realize the advantages of the Nosler Partition, while many of the rest of the boys were still wallowing around shooting standard bullets. On his later safaris he often used the 140 Partition in the 7x57, because it penetrated plenty on plains game. So there was no need for the 175.
Too many of still theorize about the great advantage the 7mm's have over the .270 due the "wider bullet selection." This one reason some give for choosing a .280 over the .270. Well, gee, but I have run into a lot of .280 users over the years, and only one loaded 175's--and those were Sierras, which on average would penetrate no more than 140 Partitions. Most .280 fans use 140-150 grain bullets--pretty much standard in the .270 these days.
I have pretty much decided that if you can't kill it with one of today's modern 150-grain 7mm's in a 7x57, then you need more cartridge, not more bullet weight.
