25 round magazines are too small for 22LR sub machine guns.
The subcaliber kit for my G3k machine gun only had 20 round magazines. Thankfully that is being fixed with 35 and 40 round magazines now
At least with the 10-22 basd SMGs we have 50 round mags available
Here is the Krinker Plinker that we built for one of the Central FL gun ranges. CJ is running through a 50 round magazine dump