ICS M4 Stripped Piston, how do I remove piston head.

[philly0001]

I have an ICS M4 I am working with my stock upper gearbox. I have stripped a tooth on my piston and need to replace the piston. I have removed and disassembled the gearbox. I have the replacement piston but my challenge is how do I remove the piston head from the piston. I need to reuse the piston head so I dont want to damage it (unless I really have to, and if so how will this affect preformance). I have read that there is a cover on the front of the piston head covering the screw. There is a tiny hole (maybe a paper clip can fit in) on the cover and it looks like it is glued in, as I can not remove it. How can I remove the piston head? Would using something like nail polish remover help get the cover off or is it just going to ruin the piston head? Or is there something else that can be done. I am holding the nut down inside the piston shaft, so it appears the screw is turning in the casing and not unscrewing. Would it be best to just get a new piston head? If so does it come with the screws needed to attach to the piston? But I would rather not spend anymore money (and waiting for things kills me) since I might as well just buy a whole new upper gearbox at that point. Any help would be greatly appriciated. Thank you.

[HKGhost]

If turning the piston head doesn't remove it, you'll need to drill out the center to expose the Phillip screw head. You can still reuse the piston head afterward but it's best to replace it with a ported one.

[philly0001]

Thanks for your reply. I thought you were going to say that. Do you recommend a certain manufacturer or type of piston head. Should I also get a new cylinder? I understand changing these will affect preformance, which is fine but I am not out to improve things (If so then good but not a requirement, I will buy a new upper gearbox-d soon for that), just looking to get this gun up and running again. Besides improved seals therefore preformance is there any other advantage to a ported piston head? Also what sort of preformance downgrade would be expected if I used the piston head with the screw cover drilled out? Could I put anything in the covers place that wont ruin the gearbox? Thanks again for your help HK. I have heard good things about your doctor skills.

[Kos-Mos]

You can use the piston head without the cover no problem... it will actually dampen the noise a litte.

And you can port the head yourself. First remove the o-ring, then use a small (1/16") drill bit and make 4-6 small holes in the front part of the head so that it arrives in the bottom of the groove for the o-ring. The point is to push the o-ring outside and against the cylinder when pressure build-up in the system.