VFC Aluminum Piston Head for Airsoft AEG Gearboxes

"WARNING - THIS IS NOT A BORE-UP PISTON HEAD - WARNING

First and foremost, this piston head is not a bore-up diameter. It is a standard piston for a standard cylinder setup. It is the same head that is included in standard VFC AEG's.

The piston head cannot be used with a bore-up cylinder or cylinder head, and it cannot work if you simply swap the o-ring for a bore-up size o-ring.

On a side note, this is the same one as found in VFC AEG's. It's decent grade aluminum, but it comes with a cheap plastic spacer instead of a bearing...really?!