We killed a lot of coyotes with a 223, bolt guns, 788's, rem 700's. These were usually our calling rifles so shots were usually 225yds and under. We tried about every bullet you can imagine as we hunted in a target rich environment.
The Sierra 45g spt is a great little bullet, so is the 50g spt.
Other than the 45g & 50g Sierra spt, We ended up shooting a few different bullets that seemed to always work. Of the 55g bullets, Hornady 55g spt with the cannalure does an excellent job and is a very accurate bullet. The Sierra line of 55's, EXCLUDING the blitz king, and we loved the 55g Winchester soft point. Any of these 55g bullets loaded with about 26-27g of Win 748 will be very accurate and deadly at approximately 3100 fps.
Through this site, a fellow board member shared a load of Benchmark that is pushing the 53g-55g Bullet at 3500 out of a 24" bolt gun using benchmark and a cci 450 primer that ended up being critical.
We shot the biggest holes in coyotes with the 223 using a 55g Sierra lead tip blitz with a muzzle velocity of about 3350, and I mean the shock and damage on a coyote is Massive, very accurate bullet also. Today, I would try that 55g Sierra lead tip blitz with a hot load of Benchmark and a cci 450.
Today, there are a lot more bullet choices than we had from the late 70's to mid 90's. I like penetration to break bones on quartering shots, so the 60g V max would be on my list of bullets to try today.
We really hated not killing a coyote outright, and you rarely ever get a perfect shot. For this reason, I like the 55g bullets. It is terrible to see a bullet blow up on a hip joint, shoulder blade, or splash on a rib. If you hit one running away from you, the bullet has to travel through a lot of bone and flesh to get to the vitals.
If you like a light bullet going fast, two bullets we used were the 40g Sierra HP that was developed for the LAPD Swat teams to shoot through a man's skull and not kill anyone on the other side in a 22/250. The other bullet that you should really treat yourself to is the Sierra 45g spt, we named this bullet mighty mouse because it will shoot through bones, and AA2015 will shoot these bullets with blistering speed(3700) with extreme accuracy. We quit using them because in Nv. the shots could get on the long side, and they seemed to run out of gas around 350 yards.
One poster said to just get a 223 and some bullets and go kill some coyotes, that is pretty much dead nuts right on.