knock'emdown, while you are impressed with the heaveir 65g Sierra, it is more of a deer bullet than a coyote bullet...tough.
I have always shot 24" bolt guns in 223 with a Sierra 55g Spt, 55g Sierra BTHP, or 55g Nosler Ballistic tip with a stout load of H322 that is going at or near 3400 fps. I do not remember many spinners or runners becase they had a huge hole in them.
When I was saving hides, I shot a load in a bolt gun 223 loaded with a 55g Winchester with 26.5g of 748 at 3050 fps.
More often than not, this soft core bullet did not go through the yote. Other guys that I hunted with, worried more about finding the coyotes that had been shot vs. the size of the exit wound. We just learned to sew up hides.
Generally spinners and runners happen because they are shot too far back of the diaphram.
In a 20" Mil spec chamber'd 223, velocity is down over what a bolt gun gives which leads to a lot of what people are experiencing on spinners and runners. As the velocity goes down, so does the size of the tempory wound cavity that is created by the bullet.
If a guy is expecting to make up for a shot too far back in the body, say the stomach area, then he needs to be shooting a 243 or a 25/06.
I checked the speed on my Colt CAR loaded with the accuracy load (26g of AA2460)with 55g Sierra BTHP and the speed was 2850 fps. While the CAR shot 3/4" groups, a 55g bullet at 2850 simply does not have a lot of ft/lbs at 200 yards, which means that I have ZERO margin of error on shot placement. Size of the chamber also something to do with velocity, not just the barrel length.
I'll tell you this, a Sierra 55g lead tip blitz at 3400 fps will often make a bad shot good when it comes to coyotes, and is super deadly at 300 yards. I guy really does not have to shoot much farther than this unless he is hunting in the Mid West where they troll and shoot them out of the truck. Shots at 300 yards should be very rare, depending on what part of the country you are in.
You guys that are shooting AR's that are having a lot of spinners and runners, you should have a good trigger put in your rifle. That factory trigger is not condusive to good accuracy and could be causing you to have poorer accuracy.
I shoot all the time. It is VERY difficult for me to sit down and shoot an AR with a 5 lb trigger pull.