If I could just ask, DT, why do you want to stick with such a heavy bullet for coyotes? Are you trying to avoid re-zeroing the scope?
I use a 100 Grain Hornady SP for deer in my .243, but then I switch back to 60 grain Sierra HP for yotes. Because the performace doesn’t vary, I just logged the scope adjustment in my reloading log and I can simply make the adjustment back/forth. It’s 7 clicks up, 2 clicks right to go from the 60 to the 100.
Depending on your scope, you can usually zero it for one load and then take the indexes off and set them to the zero position for both windage and elevation. Then when you dial in a different load, you can easily go back and forth by adjusting and then returning the settings to 0 for the original load.
There’s nothing wrong with a 100 grain bullet, but IMO it’s kind of handicapping the .243’s significant reach-out-and-touch-em potential to run that heavy of a load. With the 60 grains, I’m shooting flat at 200 and only 2 inches drop at 300. I don’t recall 400 exactly, I’d have to look in my book, but it’s still a very modest drop.
I haven’t shot at 300 with 100 grains, but I would predict that the drop is going to become difficult to manage with this heavier bullet.
Grouse