The entire point of this article is the difference between the AR-15 and the M-16. So if they are essentially the same, that means this article is pointless. That type of assertion needs some strong evidence given how well-researched the article is.
The 3 differences the article lists between the AR-15 and the M-16 are:
1. The M-16 added a useless "manual bolt closure" making it a bit heavier.
2. The M-16 rate of twist was changed from one-in-14-inches to one-in-12, which made it 40% less lethal.
3. The M-16 switched from IMR 4475 powder to ball powder, which made it much much less reliable. After tons of US soldiers died due to the unreliability, they modified the ball powder and changed the mechanical "buffer" of the rifle, which made it more reliable, but still less than the AR-15.
The 3 differences the article lists between the AR-15 and the M-16 are:
1. The M-16 added a useless "manual bolt closure" making it a bit heavier.
2. The M-16 rate of twist was changed from one-in-14-inches to one-in-12, which made it 40% less lethal.
3. The M-16 switched from IMR 4475 powder to ball powder, which made it much much less reliable. After tons of US soldiers died due to the unreliability, they modified the ball powder and changed the mechanical "buffer" of the rifle, which made it more reliable, but still less than the AR-15.