"sniperlabyo"Yes the spring advance the mag.
the lever that holds the mag, it's activated by the blow back pressure when shot to advance to the next pellet/slot
there are critical adjustment to be made for the mag to advance smoothly.
1. the mags width front to rear has to be identical ------ if not each mag will have a different blow by with the auto seal oring, that means the fps will be slower with the smaller mag. you will notice one mag will be looser or tighter with multiple mags
2. the barrel clearance to mag has to be at the minimum without binding while ejecting/cycling, adjust the clearance to the thickest mag or the clearance for both mag to have the same blow by.
to adjust the barrel clearance:
loosen the barrel 2nd screw nearest to the muzzle, the screw near the mag is the adjuster, that screw seats on a off set divot on the barrel --- when screwed in it will move the barrel aft. adjust till barrel touch the mag without jamming while being cycled--this will give you the less blow back and give you the best ES.