I think the biggest issue with the magazines are the plastic gears- any jam or misfeed and they are likely to strip- two of them are bad in the magazine I have.
Looks like the best price for a new CYMA mag is about $48 at airsoft megastore.
Interesting solution- check out what he did with the mag-
http://www.bingoairsoftworks.com/mat...ne-conversion/
here's the inside of one of the AK mags, don't see why it would not work with a little modding.
http://www.popularairsoft.com/review...-drum-magazine
looks at least a little more robust than what is in there to begin with.