[Spa]

Hey guys,

Unfortunately I can usually figure things out but this problem is weird.

Shims are working properly (Checked shism and work great)
Motor is working properly (used 2 different motors)
Used an 8.4v and 9.6v batteries, both charged.

Ball bearing spring guide
ball bearing piston head
silent piston head

Basically, I put the gearbox back together pull the trigger and it fires a good 3 round burst. But after the gearbox simply seizes up.

The piston simply gets stuck in the back near the spring guide. I know the spring is not buckling over the side of the spring guide. The gearbox simply cant pull the piston back all the way.

In the picture below is an example where the piston stops.

You help would be greatly appreciated.