Gentlemen: It's like this, often enough to keep me hoping, I've eased up to the top of a ridge, and slowly peeked over to the area below, and out farther, and spotted birds. They seem to travel in flocks, and once in a while you can guess where they might be if some food source is available that they like. Bear in mind, this is in the Autumn, when the leaves are thinned down a bit. Let's say, sometimes, 200 yards, give or take. I think much farther would be rare, too much in between.
This is rifle range, for a target of that size. And sometimes, there is even time to set up for a shot, you know, lean against a tree or something to stay steady.
Now the 22 Mag, 22 hornet H-mmm, good stuff, 25/20 I've always admired! Enough? At that range? I don't know. A larger Deer caliper would be rather destructive.
The 243 is available in an accurate, lite weight walking around rifle (as well as other choices 223, 270, ect.) and two gentlemen have stated their experiences, with that cartridge. Stopped the game and no big damage. I'm happy! Woodbutcher