170-175 gr bullets will do the trick. Ensure that your rifling twist is appropriate to stabilize the larger 7mm bullets. Two neighbors have 757s...One is a sporterized, old military Mauser that shoots the 170s just fine. The other has a much newer American factory gun that likes 140 gr and less bullets. I had a custom 7x57 Ackley Improved made and selected 1:9" (1:8" even better for the heavy pills, but I typically shoot 140s at home, so it's a compromise.) The 1:10" and 12" don't stabilize the 160s-170s so well. Many semi- and fully-custom 757s are built on Long Actions for seating the bullets way out and taking advantage of either additional powder space or hotter handloads. I LOVE my 757 AI. Super accurate. Pleasant to shoot. Choose the proper bullet, put it where it belongs and done deal every time! There's a great video out there by Mark ? of CA whereby he takes all sorts of E. African game using strictly traditional cartridges, including the 7x57 (using 175s) and fine custom rifles. There are some eland that weigh 2,400 lbs...My preference would be something larger, but the 7 will do it using the heaviest of slugs and the absolutely most perfectly placed shot(s). I could go for Eland & Eggs right about now!!!