I have the same issue with Kimber mags in my Colt SCG but McCormick mags work just fine. It takes a tremendous amount of pressure to get the slide release to work on an empty mag with the Kimber magazines.
The factory Colt and McCormick mags works just fine just as Browning and Colt expect them to do. The Kimber mags might work just fine in Kimbers.
I don't stand there all day doing it over and over and over again, but I don't get all prancy and excited about it doing it once in awhile either. Its a standard safety check afterall, you guys wanna buy guns that can't handle having their slides slam shut a few dozen times in their lifetimes thats your business. This isn't a dry fire exercise.
You'd really get excited about how the user manual explains how to get the barrel off of my 40 year old High Standard pistol. Requires using the receiver as a mini reciprocating hammer...stilll shoots 1" groups at 25 yards

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