very well said tokyo seven, but if he is refering to gamos airsoft/crapsoft line which is called the aftermath kraken which is tm compatible 100%. The AK 47 model, I first started with that to test the waters but have since moved on to CA's. Anyways getting back to it, the kraken does have a full steel mechbox and gears, it is a version 3 style mech box. I did some upgrades to mine such as pdi 140%, mad bull tight bore, piston head, cylinder, everything except for the gears!! Chronied it last week using .23s,, 330fps! not bad for a so called crapsoft. It got me in the sport, plus being compatible.
I say go for it then upgrade.