My wife and daughter have around a half dozen antelope and a dozen deer with the Ruger American Predator Gen 1 in 6mm Creedmoor with the 1 in 7.7" twist barrel using the 95gr LRX factory ammo. This barrel is twisted faster (in barrel twist, lower number is faster) than the minimum requirement of 1 in 8" and shoots like lazer beams out of our rifle. I don't like the looks of the Gen 2 rifles but would buy another Gen 1 in a heartbeat.
The Grendel is a great option if you were going to use lead core bullets but since you are limiting yourself to nonlead options, I would not use the Grendel for that option as it starts out so much slower than the 6CM. You realistically need 2000 fps impact velocity for nonlead bullets to perform the best.
The 6ARC is an excellent option but if you're limited to lead free offerings and factory loads, it probably isn't for you. Most of us using the 6ARC are using heavy for caliber fragmenting match type bullets or handloading our own offerings.
My daughter shot this antelope with the 6CM when she was 12. I'm sure your spouse would be fine with the recoil and weight.
Jay
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