I have noticed that when I use 8 round S&W 9mm shield magazines the rounds end up with what appear to be an impact mark on the primer from the slide of the gun.
Since the second factory return (1st time bad barrel/2nd time bad extractor which may have been my fault when I ran 200 rounds of 124gr+p+ hydrashock as a function test when it returned from the factory the 1st time – or the extractor could have just sucked from the factory and I didn’t know it till the barrel issue was diagnosed) it has had approximately 550 rounds through it without trouble so I have cleared it for carry using 7 round magazines.
Rounds from 8 round magazines have fed/fired/ejected without trouble and I have used a variety of JHP & ball for the test rounds, but I’m not sure if the marks on the primers from the 8 round magazines are an issue for concern or not.