100 yard zero. There's no reason to zero these types of rifles beyond that.
For really stretching the legs on these rifles, the main reason why you shouldn't zero past 100 yds is due to the environmental variables involved. At 100 yds, the zero is mostly reliant on the scope's ability to retain zero and your rifles ability to make bullets go where it's pointed. You might see wind or other factors affect its impact by 1/4MOA or so, but for the most part, at 100 yds, the bullet is going to go to zero regardless of what's happening around it, what the temperature is, what elevation you're at, what the ding-dongs in Seattle are doing, etc. When you zero at 300+ yards, you're letting all of that stuff in. Wind blows you around, air density starts to count, and if you don't keep perfect track of it then the basis of your ballistics calculator will be flawed because your zero moved for that day.
If you're worried about not having enough elevation range, pour the coals to it and throw a 40+ MOA base on the gun. If you don't have enough down adjustment to get point-of-impact down to point-of-aim at 100yds, then bottom the scope out, come up a minute off the hard stop, and let it group 5", 6", 10" high or wherever it falls, and then get it centered up for windage. Most ballistics calculators have an input for zero offset for this exact reason. You just want to be absolutely sure where your gun is impacting in a vacuum, and the closest you can get to that in our real world is 100 yds.