I alternate between using the slide lock and pulling it back and doing it manually and I have noticed no difference in feed or reliability,

I have read that with these you need a straight-wrist and a tight grip as to not let your wrist absorb the motion so the slide takes it all and is able to go all the way back. I have tried several different levels of grip, always careful not to let my wrist move or roll. Again, no noticeable difference in feed or ability to eject.

Lastly, I used some 90-grain Fiocchi rounds and the 100-grain rounds are Sig Sauer Elite Performance rounds.