He makes a good point. I feel confident that I could make a kill shot on a coyote at 120 to 130 yards, max. Anything longer than that and the bullet starts losing steam and accuracy tends to suffer. 22WMR is not exactly a "precision" round and there is no "match grade" ammo that I know of. And finding a particular brand that shoots good in your rifle will be tough due to scarcity of ammo.
17HMR is still plentiful and you can still find several different brands to try in your rifle to see which one it likes best. You'll get better accuracy potential with the 17HMR, but less punch delivered on the target. Which probably won't be an issue if coyotes are your biggest target. I have a neighbor that busts coyotes from his cabin all year long with a CZ 453 in 17HMR. He says most shots are "bang, flop" shots.
You could also look at 17 Hornet or 22 Hornet also. I'm a big 22 Hornet fan myself, but I can't think of a model off the top of my head that would make a decent "truck gun" though. The 22 Hornet fills the niche between 22WMR and 223 very nicely.
There is a Traditions Crackshot 17HMR that is only 200 bucks. Single shot though.
I might reconsider the HMR.