I have had various 243 for as long as I remember. I have shot everything from sika deer to whitetail to bobcats with a bolt action 243. Anytime anyone mentioned the ideal caliber, I always spoke in favor of a bolt action 243. Anytime anyone mentioned an AR, I laughed first and then thought that he was a city boy who had watched too much TV on what a rifle was "supposed" to look like. Anyway, I always said, a 223 isn't big enough to do any good.
The last few years I have gotten more into coyote hunting. Earlier this year, twice I called 4 coyotes into one stand. I decided I needed an automatic rifle so I could get off more shots. I looked for about a month for an auto. I had decided I didn't want a 243 because I already had several. I thought about a 220 swift or a 204, but we have a lot of wind out here, and I was concerned about wind drift. Finally and much to my dismay, I settled on a Rock River Arms Coyote Carbine in 223. I really didn't want an AR, and I really didn't want a 223, but it just seemed liked it was the best compromise of what I was looking for.
As a die-hard bolt guy, the day I went to sight in, I was already mad before I pulled the trigger, because I knew I was going to get 1-inch groups at best. I had already tried to convince myself that 1-inch groups were fine for coyotes. Within 10 shots, I had dialed in .5-inch groups. Fine, I thought, but I am going to be chasing a lot of spinning coyotes and tracking bleeders into the brush.
The week before I had shot a coyote with my 243 that I had to track 100 yards. When I finally found him, I had made a great shot, but the bullet went right through and left tiny entry and exit holes (this had much to do with my bullet selection), but I was not happy about having to crawl through the underbrush to retrieve the yote.
So I handload some Nosler Ballistic Tips in 50 grains for the 223, and I grab the caller and head out. The very first coyote I call in runs up to 75 yards and turns broadside. I lay the RRA on a tripod, put the crosshairs behind his shoulder, and squeeze off a round. First, I notice that I get no muzzle rise and that I get to see the whole thing go down and not have to wait until my scope settles like with my 243. The second thing I notice is that the coyote is hit, and he simply rolls over DEAD. He didn't take a step. I was shocked once again. I went out to pick him up, and he is leaking goo. The bullet vaporized his insides. I have since seen 4 other coyotes go down to the AR 223 and none have moved more than a yard or 2. Most die where they stood when shot.
I say all this for two reasons. One, I was the guy making fun of people with ARs. I thought good old country boys like me were supposed to shot bolt actions because that is what granddaddy shot and because I had always been told they were more accurate. Well, the AR is as accurate or more than my bolt guns. I still don't like the way it looks because I am afraid that the ranchers where I hunt are going to freak out when they see me lugging it around. But, nonetheless, I am sold on the AR platform.
Second, the 223 is a plenty mean round if you shot the right bullet. I like the lack of recoil and muzzle rise. It reloads easily and there are a lot of choices in bullets. I have only loaded 50 grn NBTs, and I see no reason to load anything else right now, but it is nice to know I have some options.
If I could only have one rifle for all my needs from varmints, to predators, to deer, I would not go with the 223 (or probably even the 243 for that matter). But if you can afford to have a dedicated varmint/predator rifle, I am impressed with the 223---and I wouldn't be afraid to step away from the bolt action even though granddaddy may disapprove.