For the last four seasons my go-to rockchuck shooter has been my .243. It's a 24" barrel with a 1 in 10 twist which stabilizes up to a 100 grain Hornady BTSP just fine. My long range bullet is the 87 gr V-Max. However, 55 gr Ballistic Tips, 60 gr Sierra HPs, 58 gr Z-Max, and 55 gr Sierra BKs all shoot to virtually the same point of impact and I use them for the closer distances. With the Varmint Hunter reticle in my VX-3 I have solid holdovers out to 600 yards. Anything farther than that I have to dial.
This is a picture of a first round hit at 725 yards with an 87 gr V-Max this spring.
These were taken with the lighter bullets out to 400 yards.
The only good thing about coyote season coming to an end is the fact that rockchuck season is just about to begin!