Note: this is on my TM body and might not be the same for kraken, but should be the same.
Ive found a solution a while ago to the fix the mag wobbling.
-on the video, go to 4:10, and you will see a small part come out of the receiver. This is the piece that the mag clips into.
http://www.mechbox.com/ak47/ak47-disassembly.html
- I used some electrical tape and put some on the lower lip that the mag edge clips on, and this will fill the small gap.
dont use too much, as the mags might not fit. use your common sense as to how much to use.
As for the Hi-cap, I have one, and use it among my 8 other mids and lows. I like it for like a last stand or heavy firefight. Other than that it makes too much noise and I hate winding.
cheers
simple fix