I don't know why you'd want a 30rd mag for coyotes (or a separate gun for that matter), but from how I'm reading the regs (I'm not 100% sure about this), if you are out during Deer rifle (on public land) hunting for coyotes, you have to adhere to the legal means of taking whatever is in season.
This is why for Hogs, I can't have a 30rd mag during Deer rifle, but any other time of year, there is no limit to mag capacity for hunting hogs - now it goes a long way to say that if a game warden is out, you need to know that they don't all know every reg, so I'd have a copy of the regs with me if you wanted to push anything (hunting hogs/coyotes with a suppressor is one of those issues - technically, they're not game animal, so it is legal, but try explaining that to a game warden that doesn't know better).
Here's where you can find hunting regs for all of the various seasons:
http://wildlifedepartment.com/huntregs.htm
Centerfire rifles firing at least a 55-grain weight soft-nosed or hollow-point bullet and having an overall cartridge case length of 1 1/4 inches or longer (9mm rifles are not legal). Clips or magazines of all .22 caliber centerfire firearms may not be capable of holding more than seven (7) rounds of ammunition.
Number of rounds for deer is only limited on .22 caliber centerfire.
My question would be this: .223 is 3/1000ths bigger than .22, is it still .22 caliber? The engineer in me wants to argue that point.