Not sure if it's zmack or aluminum both the slide and frame. I can't find any spec's what it should measure at. I had the calipers out and it's nowhere near the same as a true 1911. My Chiappa 1911-22 is closer to a real 1911. The slide groves where it rides on the frame rails still has the finish on it. The frame shows wear towards the rear. From what i see parts are on ebay for used ones. I can get more than enough to buy a new GSG with a lifetime warranty.
How does the gun shoot? Generally, slop between the frame and slide does not effect the accuracy of the firearm as badly as slop between the slide and barrel.
The barrel , slide and SIGHTS are all inter related as a unit, all independent to the frame. The slide to frame slop has little impact on accuracy. The critical fit is between the barrel and slide having the same position every time the gun is at battery.
It's been shooting fine. Last outing it stove piped a few times. I chalked it up to over oiling the action. When i came home and cleaned it up and re-oiled with less. That is when i noticed the extra play. I plan on taking out again tomorrow. The barrel on the colt rail gun 22's are mounted to the frame.