@fountainhead thanks, and other than just having an itch for something different, the ballistics were actually a big part of why I wanted to build around this caliber. It is pretty popular with the hog hunters because of the stopping power on a big boar, so it will be overkill for anything I will level on with it.
At 100 yds, it is pretty flat (0" to 4" or 5") depending on the bullet, 300gr is pretty flat, 500gr the drop starts a little sooner. That is pretty consistent across ammo brands. For 300gr or 325gr ammo, that runs on out to about 150 yds. After that, they start dropping off pretty quick. And at 100 yds, a 300 grain round on average still at about 1500 fps, 1200 fps at 200 and so on.
Between 200 and 300 yards drops of over 50" seem pretty standard and beyond that think of a lead bar in a pool.
This actually is what I was looking at from a responsible shooter standpoint. This will be a coyote/ farm gun and if I pull up on something around the house, knowing that out past 200 yards it is falling like a rock gives me peace of mind. There are no structures within 200 yards of my house and at that point I am only off my property on 1 side. Having a round that is ready to eat dirt before it is over the property line is peace of mind for me.
I think I may have to play with the buffer and spring setup to get a good runner, but I am looking forward to getting a few rounds thru it.