Jake - This Mec-Gar magazine will fit and function well in your ATI, or any full size, or commander size, single stack, 1911. Mec-Gar produces many of the 'original equipment' factory magazines for manufacturers of various 1911s, and many other type pistols. They produce a good quality magazine, and the price on these is a good price.

Yes it will fit the commander size 1911 with no issues I use these in my 1911s and can recommend them

Jake, yes Sir. This magazine will work in Commander or Government Models as designed. No worries.

Jake, Absolutely this 8 round magazine will fit and function in your ATI 1911. You can get 15 and 25 round 45 ACP 1911 magazines that will fit and function in this firearm also.