I love mine, it’s one of my most fun guns. I probably have over 15,000 rounds through it by now. I have the 522 conversion kit, 9” Dlask barrel, fixed stock, flashlight forend, and several 3D printed parts. It looks very similar to an MP5 and I get questions/compliments on it all the time at the range. The short barrel makes the .22 sound much louder than it should. Several people thought I was firing a 9mm MP5 … I wish!
I haven’t had any issues loading my mags to the full 24 rounds. The mags do “split” ever so slightly, but I haven’t had any issues with feeding, or lasting damage to the mags.
Mine is extremely ammo picky. I’ve tried every round I can find. If yours is picky too, try running some round-nose ammo through it. Mine loves CCI Mini-Mags, copper plated round nose (40g). Hollow-point ammo is very unreliable.
One thing that could be improved upon by quite a bit, is the trigger. It’s very spongey as mentioned above, and it does feel cheap (but it is a cheap gun after all).