Mossberg 500 shotgun- upgrade or buy another gun
That should be plenty for what I need. I also foresee an AR in my near future, but that depends on if my buddy ends up selling his
But I know what you mean about a certain gun being your all around gun. The remington 870 was my first gun and Ive got a strong affinity for the 870. But if you can afford it then start diversifying. A shotgun on small game is overkill plus youll be chewing on lead BBs. A shotgun slug on deer bruises and ruins a lot of meat. Like a previus poster said, coyote hunting can be with almost anything you like, dont worry about diversifying there unless you really get into the sport and start killing more than a few coyotes every year.
Just use 'big game' bullets in the 243, does just fine.
IMO deer hunting without any sights on a shotgun is one very small step above being unethical. You don't point a slug you aim it and you can't do that with a bead. You could go with a rifled slug barrel but I would MUCH rather have a rifle than a slug gun for more range, better accuracy and more power. Most people don't really need a special coyote rifle as 95%+ of coyote hunters in this state don't shoot more than 1 or 2 per year, just buy a nice deer rifle in 308, 270, 30/06, etc and use it for coyotes also. Pelts are worth next to nothing so why worry about what the bullet does to the pelt?
I would also pick up a 22 as they're great fun to shoot cheap ammo with and if you like squrell hunting a 22 makes it into hunting vs shooting with a 12 gauge.