Which ati If it is the ATIGFX9GI that is what would be called a commander size 1911 IE full size frame with a short barrel any standard size 1911 9mm mag will work just fine. The MGCGOV9LB is a very good mag and will work great

It will probably work. You may have to load it down to 8 rounds to get 100% reliability or try a different brand. 9mm 1911's can be a problem. The gun was designed in 45 so the 9 has quite a jump to get into the chamber. I use Wilson mags with the metal follwer other competitive shooters swear by Tripp magazines.

Yes, this will work just fine Frank. The model MGCGOV9LB is highly recommended as Mec-Gar is a manufacturer of a lot of OEM magazines.