While there is probably no perfect answer to your question, the best answer is, "it depends". I say that cause a 70yd shot with any magnum caliber is going to do a lot of meat damage. High velocity is devastating to meat. I just killed a small mulie buck with my 308 and 150gr Nosler Etip bullet. The entry and exit holes were almost at caliber size and about a 1.5" circle of damaged meat.
Why? Two reasons, first, muzzle velocity is about 2600 (compared to yours at about 3200+ I am guessing) and second the shot was at 180yds. He ran 50 yards and dropped dead. There is nothing wrong with the caliber you chose, IF you anticipate some 200+ yd shots being the norm. If all your shots are going to be the average American hunters 150 or less, then you might be a little overgunned, at least with factory ammo.
If you expect to encounter more of the close shots, I'd look for a slightly tougher bullet, one that's meant for tougher game. Remember, it's purely velocity that opens bullets. Softer bullets are best to use if the shot is expected to be long, since they open at lower velocities, the bullet will have bled a lot of speed by 250yds, and the meat damage will not be as bad. If you purchase ammo with tougher bullets, it may not open fully on an antelope, but I suspect at 70yds the antelope would never know it.
Maybe others with your exact problem will have better info for you. The good news, is since it's a Savage, and you decide to change calibers, it doesn't mean having to buy a new rifle. A 260 Rem would still shoot very flat, have less recoil, and most likely ammo would be less, not sure there though.
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