[hot_shot under fire]

I had the same issue with my A&K Masada a while back. The issue was I was using the stock battery (8.4v 1200mAh). Due to the lack of power the battery provided, my motor could not cycle properly. This resulted in a rather nasty smell coming from the grip in addition to the grip and battery becoming extremely hot.

Easiest fix was to switch to a more powerful battery. In my case a 9.6v 1600mAh worked very well. Well, that and a spring change to a lower power spring as the gun was pre-upgraded to conform with any laws posing an issue for importing guns below 366fps and above 500fps (I may be off with the fps readings here, but that's what I recall them to be- Feel free to correct me)