Laker: The 204 Ruger is the superior cartridge - especially at the ranges you will be shooting - for NUMEROUS reasons not the least of which is lethality, flattter trajectory, less wind deflection, bullet speed and lack of recoil.
Reconsider using the wonderfully accurate Sierra 52 grain bullets from a 223 for Varmints - these bullets are hard as nails and lethality on Coyotes is oftne "iffy" - at BEST!
The 50 grain Nosler Ballistic Tip is a very lethal projectile for Coyoting though!
Best of luck with whichever you choose - get after'em theres lots of Coyotes out there.
Hold into the wind
VarmintGuy