This has been explained to you numerous times. When Colt acquired the rights to the Armalite Rifle 15 they changed the name to Colt c601 which the government then branded M16. They still retained rights to the name AR 15 and applied to the semi auto that was not designed for the battlefield. Spend less time with strike thru and more time reading.
Acknowledge you have been answered, AGAIN, answer the questions you are running from, and tell me this:
If the SP1 was designed for the battlefield, was really an M16, why the different lower with different branding? Makes no sense from a business standpoint.