King Arms version 3 7mm bearing gearbox
 

Does anyone have any experience with this gearbox? I am curious about the quality of the 7mm bearing bushings, and if they are suitable for a guarder sp120 spring.

thanks

I have had one for a couple of years now, and love it. I first had it in an ak 47 and didn't actually put too many rounds through it that year but the year after turned it into an RPK and its seen MANY rounds now and seems to be awesome! Prob have about 100 000 rounds through the mechbox now and I actually inspected the mechbox last months and it looks great. Most of the time (if not the whole time) its been shooting very close to 400 fps.