Who was the maker of the AR 15 Rifle?
The AR 15 was designed in 1957 by Eugene Stoner. The original manufacturer of the AR 15 was ArmaLite, but they sold the rights to Colt's Manufacturing Company in 1959.
When Armalite first developed the rifle, they gave it the nomenclature of AR-15. When they sold the rights to Colt, Colt continued using the AR-15 name, and applied it to all variants of the rifle (usually accompanied by a model number). M16 is a military nomenclature - the rifles are still AR-15 rifles, but built to certain specifications, as required by military and law enforcement customers.
DPMS doesn't make an AR-15 - AR-15 is a copyright of Colt Firearms, and thus, only they and companies licensed by them to manufacture the rifle can actually call it an AR-15. As for their AR-pattern rifles, they typically come with a 5.56x45mm chamber, which is also capable of handling the .223 Remington.
The M16 assault rifle originated as the AR-15, designed by Eugene Stoner (1922-1997) at ArmaLite in 1957. The AR-15 itself was a scaled down version of the 7.62mm AR-10. ArmaLite sold the design of the AR-15 to Colt, which submitted the rifle to the United States military command for testing. It was subsequently adopted into service in 1963 as the M16.
I assume you mean how is an AR-15 rifle made, so here we go: The AR-15 is based on the 7.62 mm AR-10, designed by Eugene Stoner of the Fairchild ArmaLite corporation. The AR-15 was developed as a lighter, 5.56 mm version of the AR-10. The "AR" in AR-15 comes from the ArmaLite name. ArmaLite's AR-1, AR-5, and some subsequent models were bolt action rifles, the AR-7 a semiautomatic survival rifle and there are shotguns…
It depends on what you mean. Most people use the term assault rifle incorrectly. If you mean an AR-15, that is not an assault rifle. That is a semi-automatic magazine fed rifle, or, in current terms, a modern sporting rifle. AR-15 rifles are legal in every state in the U.S. as far as I know. Real assault rifles are legal in most but not all states, under certain restrictions.
AR-15 is a manufacturer's designation. When Armalite designated the rifle the AR-15, both fully automatic and semi auto only rifles were dubbed as such. M16 is a military nomenclature. Now, the AR-15 rifles you can buy at your local gun store without having to obtain an NFA Class III permit - those are semi auto only.