The 270 is more powerful. The .270 has a slightly larger projectile in diameter (.277 vs. .224) and a significantly heavier bullet (between 90 and 150 grains, vs. 45 - 80 grains for .223/5.56 loads). Additionally, the .270 utilises a much larger casing - the .30-06 casing, necked down to accommodate the smaller projectile of the .270 cartridge.
No. The .243 is a larger calibre, and the parent case is the .308 Winchester, necked down to accept the smaller projectile. It's considerably more powerful than the .223.
.223 caliber or 5.56mm.
WHICH rifle? There is more than one type made in this caliber.
The AR 15 is a rifle, not a caliber. the .223 is a caliber. Usually the AR-15 is made in caliber .223.
.223
The 223 is considered a Short Action rifle.
1000m
It looks like if it is a centerfire caliber you can use it. So, yes you can use a .223 caliber rifle.
The M16A4 assault rifle is chambered for the 5.56x45mmNATO cartridge, which is of the .223 caliber.
Short action.
@ 3 miles
The .243. It's basically a necked down .308 Winchester.