Ok, long term test report here...
3 years worth, anyway...

ZERO issues with any of my S&W .45acp mags
used in my CS45. None. Nada. Nothing.
Doesn't matter if they are 6-rd or 8-rd.
They all work just fine with standard range ammo.
I use WWB, Blazer Brass, & Perfecta as range ammo.

I do keep a Snug grip on it, so there is zero
chance of limp-wristing as well.

I honestly wonder if that little ridge was simply
a cure-all for couch potatoes who didn't have the
proper hand/wrist strength to hold the pistol
correctly when firing...

Or maybe it only happens with really hot ammo??
I may have to get some Buffalo Bore boxes,
or my Wifey's Hot Loads we're working up for
.45-SUPER conversions...might be worth a test
run of 50-100 of the superhot stuff??

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Marlin & Calico Specialist