If you have a G42 or a G43 then I know that some of your thoughts are “I love this gun, it’s perfect, I only wish it held more rounds.”
I too have thought the same thing and I did something about it. When I first got the G42 there was nothing extra for it yet, and the same for when I got the G43. Now that both have been out for a while there are several after-market accessories to increase magazine capacity. I’ve tried about 5 or 6 of them and out of those I like 2.
The main one that I’ve tried with other small handguns is MagGuts. The MagGuts simply replaces the factory spring and follower with their proprietary ones. The smaller follower and special spring allow for an additional round in the magazine. So for the G42 and G43 the factory magazines can now hold 7 rounds instead of only 6.
Sure my first thought was reliability so before I would carry any of these magazines in my gun for concealed carry, I ran at least 250 rounds through those particular MagGuts operated magazines. The result…not one single malfunction. True, neither of those magazines have every had a problem and I have not tortured them by dropping onto the ground, running them dirty, etc. I have kept the magazines loaded 24 hours a day for the past 6 months and still no problem.