I have tried them for pocket carry with 9mm single stack magazines. I have 7 round or 10 round magazines depending on the EDC choice that day. Several rounds will be loose in my pocket at the end of the day with the 7 round magazine. The 10 round works fine. I’m pretty sure the difference is not feed lip retention, but rather the 10 round magazine bottoms out in my pocket. As I go about my day sitting down and standing up pulls the rounds out of the 7-round magazine.
The 7-round is for a Sig Sauer P938. The 10-round is for a Springfield EMP 1911.