So I have a few 1911’s in the stable, some with the series 80 safety (some even with the Schwartz), and then some that are series 70.

My question is why is it in the manual to not depress the grip safety when taking off or putting back on the slide to the frame? I get it with the Kimbers with the Schwartz safety as a lever pops up and can be damaged though it shouldn’t matter on the series 70 guns right? What could possibly be damaged by depressing the grip safety with dis/reassembly? I’ve seen videos of people doing it both ways without issue. Is it more of a safety CYA from manufacturers to prevent the hammer from falling?

LincolnSixEcho - This is very interesting. Are you referencing a Colt manual? I've owned many Colt 1911 pistols and do not recall seeing this warning (though admittedly I don't ordinarily read manuals cover to cover). When I assemble a 1911 pistol, I begin with the slide upside down on my work surface so activating the grip safety doesn't naturally occur. Like you however, I find it difficult to believe there is damage potential by simply depressing the grip safety during reassembly. I'm curious to learn more. Thanks!

I've never heard of this either. When I reassemble a 1911 (Series 70 & 80), I hold the grip as I would when firing and attach the slide. I never paid any attention as to whether I was depressing the grip safety or not.

It’s weird that it’s in the Ruger and the Springfield manuals. I called and they don’t even know why other than to make sure the hammer doesn’t have a better chance of falling. Keeping the finger off the trigger will help that though.

It’s not in the Colt manual.
It is in the Roger manual but don’t have one to see what happens in the frame. A series 70 or 80 Colt or like pistol shouldn’t have an issue.

After reviewing the instruction manual for the Ruger SR1911, I have concluded the verbiage was recommended by Ruger's Legal Department. I also watched their "Tech Tip" video for assembling the SR1911 pistol which at no point cautioned against depressing the grip safety during reassembly.

From the SR1911 instruction manual.

Align the slide with the rails on the frame and gently push the slide onto the
frame . . . Do not squeeze the grip safety while putting the
slide back onto the frame.