Marc, yes sir, This ProMag AR-15/M16 9mm Magazine Quick Change Adapter block is designed to allow you to convert your standard pattern AR-15 magazine well to accept 9mm Luger SMG style magazines. The Pro Mag AR15/M16/9mm Quick Change Mag Adapter Block lets you use Colt 9mm SMG magazines with a 9mm upper in your AR15. This AR 15 Parts from ProMag installs easily when you need it and is easy to remove when you want to change back to standard ammo. The 2-part design of the Pro Mag AR15/9mm Mag Adapter Block allows installation and removal without the need to take your gun apart. Hope this helps.

Absolutely it will. Mr. Josh T. Below laid it out perfectly for ya!