I have loaded bullets from 120 to 175 grain in the 7x57 for hunting over the years. They all work when pointed right, which is what I've found with hunting bullets in general. A case could be made for using, say, 120's on pronghorn or 175's on moose, but in the real world there isn't nearly as much difference as most people believe. Load a 120 and a 175 to maximum safe velocity (say 3000 fps and 2600 fps), sight them both in 2" high at 100 yards, and the difference in trajectory at 300 will be about 4 inches. If you know your load's trajectory, either will be effective.
But I have found that there is a signficant difference in wind droft between light and heavy bullets, which is not nearly as predictable as trajectory. So with many hunting rounds these days I tend to pick bullet weights somewhere in the middle.
Also, I like to use "standard" bullets, because they're cheaper, a lot of readers use them, and because there's no reason not to, if velocity is kept within certain parameters. Over the years I've found that at 2700 fps or so do, standard bullets hold together quite well on deer-sized game, and also shoot flat enough and retain enough velocity to expand all the way out to 400 yards.
So these days I am loading bullets in the 160-grain range in my Serengeti 7x57. The load I use with all of them is 46.0 grains of H4350, and muzzle velocity runs from 2650 to 2700, depending on the bullet. As a general load I use the 160 Sierra GameKing, which works great for sighting-in and deer-sized game. All the other loads shoot close enough to the Sierra so that if I decide to hunt wildebeest or moose or whatever, I can just put some rounds loaded with 156 Norma Oryxes or 160 North Forks in the rifle and go hunting.
So far this has worked fine. I haven't shot anything at 400 yards with the rifle, but have killed a couple of animals at 375 or so (with the Sierras). Have also taken wildebeest and moose with stouter bullets.
Nosler lists 46.0 grains IMR4350 as maximum with 160-grain bullets in their manual, and H4350 is generally slightly slower. I have not had any of my loads pressure-tested, but none show the slightest sign of high pressure, even in warm weather, and brass life is great. So I assume the pressures are OK in my rifle.
But maybe next year I'll go on a 120 or 150 or 175 kick. Who knows?
John,
FWIW - When I shot my first red stag with the 7x57, the 140 gn X bullet went through and dropped it on the spot. It immediately took me back to an article I read many years prior from J O'C when he shot a grizzly with a .30/06 and a 180gn Remington Bronze Point and recounted that he made up his mind right there, that if the 180 shot clear through grizzly, there was not point every going up in bullet weight.
Now these days we know that bullet construction is a far greater influence on penetration than bullet weight, but I came to the same conclusion with 140's in the 7x57 case after getting the same results on wild horses, even with lengthwise shots.
I do load heavier bullets and have killed smaller game that the aforementioned with those heavier bullets, but the reality is that little case is a dream to shoot and permits shot placement that permits effective kills out of proportion to the necessity, invented and perpetuated in the average rifleman's mind.
Having said that, I load two standard weights these days, 140 and 175. The 175's are loaded "because". We know what that means.
John
