Those suggesting the AR-15 was NOT developed as a weapon of war should read up on history. The AR-15 was developed as a military weapon to replace the M-14. Eugene Stoner designed it to be lighter and more lethal than the M-14. It was far deadlier than the M-16 used in Vietnam.
As a longtime gun owner and supporter of the Second Amendment, I agreed with the Supreme Court’s "Heller" holding that concluded Americans had the right to keep and bear arms. But that constitutional protection did not, and will not, extend to guns designed as weapons of war.
First off, the AR-15 (as we know it) is a semi-automatic-only variant of the select fire (semi-automatic and fully-automatic) M-16. So, no, the AR-15 is not "far deadlier" than the M-16 since they're the same basic design.
Other than certain parts of the trigger group, M-16 and AR-15 parts are interchangeable. Colt quite literally used older M-16 parts in the AR-15s they sold on the civilian market way back in 1963. Here's a good video on early AR-15s/M-16s: https://youtu.be/Jowv167KdbM
The AR-15, or really the original AR-10, was designed to be very light. The concept was to use aircraft-grade materials to produce a light rifle. The idea that the AR-15, chambered for a much smaller 22 caliber round, is more "lethal" than the 30 caliber M-14 is highly dubious.
In fact, the M-14's larger round was considered one of its main advantages over the AR-15/M-16 when they were initially tested by the Army. Lethality is something of a matter of opinion. It's just that the vast majority of people tend to believe the larger round is more lethal.
Scarborough is right that many historians believe the M-16, after its own problems that mostly stemmed from some bad logistical changes being made when it was first adopted, was a far superior combat rifle than the M-14 due mainly to its reduced weight and improved reliability.
For some bizarre reason, though, he claims several times in his thread that the AR-15 is more deadly than the M-16 which is pretty bizarre since the AR-15 sold on the civilian market since 1963 is literally just a semi-automatic-only version of the M-16.
It is true that the AR platform was originally designed by Eugene stoner with a military contract in mind. And it's true that a variant was eventually produced for military service (the M-16). This is also true for pretty much every kind of gun you can think of.
Bolt action rifles, pump action shotguns, semi-automatic pistols, and revolvers have all been adopted by the US military and pretty much every military on the planet. Many designs popular on the civilian market today were originally designed for military contracts.
The 1911 is an example of this. The M1A is a semi-automatic-only variant of the M-14. The Remington 870, America's most popular pump-action shotgun, is used by the US military. Variants of the bolt-action Remington 700, a popular hunting rifle, is used by the military. An so on.
I would be interested to know what guns @JoeNBC owns because it's likely their basic design was created with a military contract in mind or they've been used by the military. I'd also be happy to calmly discuss this further with him. There is a lot of interesting history here.