Man, these "one gun to do everything" questions are tough. It's tough because one usually won't cut it, unless you can compromise in areas.
My first question would be, how much are you going to be shooting it? If you are going to be shooting the snot out of it, that's definitely something to consider. Personally, I've settled on two calibers. Those are 5.56/.223 and .308.
I chose the 5.56/.223 because it is available in both the AR and bolt guns. The caliber is more than adequate for small stuff and some get by with it on larger stuff, with proper shot placement. Practice ammo is fairly cheap and I've seen MANY stock ARs shoot match/varmint ammunition with MOA accuracy. The barrel is also going to have a long service life; something approaching 10K rounds (or more), depending on how you shoot it. Shooting an AR out to 500 yards won't be a problem either, with the right ammo.
I chose .308 for something with a bit more thump and for longer ranges. I'm not going to tout the .308 as a long range round, because it isn't; but pushing it to its limits is fun too. The big advantage of the .308 is that variations in ammo abound. There is almost no limit to the combinations that you can come up with and the caliber seems to possess and inherent accuracy. Barrel/throat life also seems to be around 5K rounds or more.
.22-250 does shoot flatter and farther than .223, but barrel life is usually something around 1500-2000 rounds. .243 shoots farther and flatter than .308, but has a shorter barrel/throat life.
Considering that you want to use the rifle for everything, you have to figure that you're going to shoot it a lot.
My first question would be, how much are you going to be shooting it? If you are going to be shooting the snot out of it, that's definitely something to consider. Personally, I've settled on two calibers. Those are 5.56/.223 and .308.
I chose the 5.56/.223 because it is available in both the AR and bolt guns. The caliber is more than adequate for small stuff and some get by with it on larger stuff, with proper shot placement. Practice ammo is fairly cheap and I've seen MANY stock ARs shoot match/varmint ammunition with MOA accuracy. The barrel is also going to have a long service life; something approaching 10K rounds (or more), depending on how you shoot it. Shooting an AR out to 500 yards won't be a problem either, with the right ammo.
I chose .308 for something with a bit more thump and for longer ranges. I'm not going to tout the .308 as a long range round, because it isn't; but pushing it to its limits is fun too. The big advantage of the .308 is that variations in ammo abound. There is almost no limit to the combinations that you can come up with and the caliber seems to possess and inherent accuracy. Barrel/throat life also seems to be around 5K rounds or more.
.22-250 does shoot flatter and farther than .223, but barrel life is usually something around 1500-2000 rounds. .243 shoots farther and flatter than .308, but has a shorter barrel/throat life.
Considering that you want to use the rifle for everything, you have to figure that you're going to shoot it a lot.