@Kevin Peacocke I've hunted a great many animals with a 7x57. My son uses a 7x64 which is practically the same thing.
The combined tally is roughly like this:
2 Kudu
1 warthog
1 bushbuck
1 duiker
2 hyena
1 waterbuck
20 impala
3 zebra
1 wildebeest
1 eland
1 gemsbok
And a ton of other stuff I can't quite recall.
The 7x57 was using 175gr Nosler Partitions. Heavy for caliber is really essential for the bigger stuff using a 7x57 in my opinion. A good bullet is truly key, and I'm not so sure that a nosler partition is always a good bullet. A 175gr Swift A-frame in a 7x57 is all a man needs for non-dangerous game.
Things that didn't go so well: My son used a 140gr barnes ttsx on an Eland at a distance of 50-75 yards. He's a crack shot and he indeed put the bullet into the heart of the eland. NOT ONE drop of blood. The trackers ran off chasing the herd and it was a cluster. Hours went by and we were about to give up, when a smart tracker walked 200 yards from the shot into some heavy grass and found the eland dead. In all the commotion, the eland wasn't observed splitting off from the herd. Bullet made it to the heart and killed the animal, tracking was miserable and would have been lost without the attention of a dozen people, even though the eland went only 200 yards.
For an Eland, you simply need to make a bigger hole in the animal to assist in tracking it in cover. It will die, but you're following spoor, not blood.