when i took the box at the shop for a through inspection before i took it apart to get my gun back
first i started with mitsutoyo digital micrometer i was close but not enough precise for me
then took the zephyr lazer at inpection post and run a real life 3D of the inside of the box
mesurement X-224.89mm y-149.97mm Z-45.03mm
so i guess the box wasn't that good after all
Which section's box is that? And what temperature? Good to see that you have looked into this deeper than most.
I have full access to equipment for even tighter measurements than that, and I would gladly give it a try (and give a detailed report) for my section's box.
The aluminum is a bit of a question mark for me. Since when do we shoot aluminum guns? The co-efficient of expansion for aluminum is twice that of steel. There may be composite or aluminum grips but all barrels are steel ( stainless or carbon), and barrels and slides are steel. In other words............. the box will expand and CONTRACT twice as fast as a steel gun being put into it. Might just be a few thousandths of an inch, but that could be enough to put you in Open class too.
There are just too many variables that can be brought up. I think the problem some people are worried about is a DIFFERENCE in the boxes. In other words, your gun may fit tightly in one box, but not at all in the other. This is the tolerance (is that right Quigley?) at play. Unless you know the exact dimensions of the box you tried your gun in the first place, you don't know if that is on the high or low side of the tolerance. The next box may be different, yet still legal.
Obviously the smart money is to make everything a little loose just to be safe. I am just going through this myself as I am getting my Para-Ordnance equipment ready to pass the box test (first I had to dust it off). I machined my old Viper bases (now Josko sells them already done) and then realized once I milled them all exactly the same, that there are subtle differences in the magazines that will affect the box test more than anything else. Some are closer than others to just squeezing in when they are in the gun. I will take a little more off all of them to be sure.
Now that I have wound Quigley up by playing "Devil's Advocate", my work is done.
Bottom line..........make it loose in the box!!!

You aren't going to win or lose points by a few thousandths of an inch on your mags or magwells.