ah i hate having to do trial and errors. I've done it too much in the past. It seems like a sweet upgrade considering the new battery i'd like to install.
Edit, im confused as to the way this website adverstises it.
http://www.airsoftpost.com/product_i...54a2a29e0ba0c7
so its ONLY for 6mm gearboxes? but the picture indicates u can have 7mm bearings...