The M4A1 carbine is chambered for the 5.56x45mm NATOcartridge, the same as the assault rifle it was derived from, the M16. It is also capable of firing the .223 Remington sporting cartridge.
5.56x45mm. It is dimensionally similar - but not identical - to the .223 Remington.
5.56 x 45 mm
10 years in prison. The M4A1 is a fully automatic rifle, made after May 1986, and cannot be possessed by private citizens.
Yes
Best will be determined by intended use, your pocket book, your skills and what is available
3.2 ft-lbs. That is more than a .22 rifle, but less than many others. PS- my grandaughter shoots one of my AR rifles (same caliber) and she is 15.
$1,032 per rifle according to the DoD
The standard caliber of a biathlon rifle is .22.
a .22 caliber
A .177 caliber air rifle has very little recoil.
.223 caliber or 5.56mm.
No You could build a rifle in .306" or any other caliber but you are likely referring to 30.06. A 30.06 rifle is referred to as "30 Caliber" but to be accurate it is nominally .308"