This is for the future but would like to have a rifle primarily for practice but might use it some for coyotes. It needs to be highly accurate
and have a long barrel life as it will be shot a lot by myself and by my grandson. I was thinking of either a 222 or a 243 as it could serve as a light hunting gun. Both have a rep for inherent accuracy, I've experienced this in a 243 as my daughter has one and it's hard to load the most accurate handload as almost all loads are accurate. From what I read the 222 is also super in the accuracy department. The 222 takes half the powder to load. Also have even considered
the 17hmr. Opinions and Experiences, Please!!
Thamks Ray

Ray,

I would put the 17 HMR further down on the list.
A good cartridge but if you hand load, I have sort of lost most of my interest in it. I look at it as an alternative to my beloved 22 mag.

Never was lucky enough to own a 222 but have loaded several for friends. Very accurate, but for economy and being able to shoot a lot, a 223 is just as good. I own and shoot 223 a lot. I have 6 rifles chambered in them, and with Lake City surplus brass, you shoot until the cows come home.

I also have a batch of 243s. It is the most versatile of the three cartridges you mentioned.
If you go with that or a 223, I recommend a fast twist barrel such as 1 in 8 twist. That way you can take advantage of the longer target bullets which really do extend the range of both of these rounds dramatically. Don't use them as hunting bullets tho, at least not on deer.

a 223 with an 80 grain bullet, or a 6mm Remington with a 115 grain Berger target bullet are some "efficient" and cool looking rounds, that perform for accuracy, " as good as they look".

1000 yd target shooting is not out of the question with either combo.

Just some experiences on my end, hope that helps out. Good luck with the project.

Get a .223.
Cheap commercial ammo.
Easy to reload for.
Low recoil and muzzle blast.
I don't know if there is a commercial bolt rifle with a 1-8 twist but there are plenty of 1-9 bolt rifles that will shoot rounds up to about 70 grains. with ar15 or custom barrels you can get from a 1-6 twist on up.
.243 is a very good round,but you get much more muzzle blast and a touch of recoil. barrels wear out much faster. The only positive is that you can also use the rifle for small deer and antelope.
Get an AR15 with a match barrel and float tube and not only will you have a fine target and varmint rifle, but your grandson will think you are very cool.
Covey

If its "primarily for practice and coyotes", and you need something that could kill a deer in a pinch (although not legal in Colorado, I think), then a .222 is a great choice. Unfortunately, you won't be able to find one, because very few manufacturers chamber this round any more. The broadly popular .223 is so similar in performance (and cheaper in ammunition) that you would be well-advised to go that route.

I like the idea of the .222Rem. It's an amazingly accurate caliber. I have two, and they are my favorites. The .243Win. is also quite accurate in the right rifle although you won't get near the barrel life from one as you would in the .222Rem. However, I don't know of another 6mm that would serve your purpose any better. Best wishes.

Cal - Montreal