Piston tooth being worn down

[georche]

My ICS M4 was acting funny...I would pull the trigger and it wouldn't fire but you would hear a light clack or knock...but it would only make that sound once per trigger pull. Switched to full auto and the same thing. Switched back to semi and nothing again. Put in safe then back to semi or full auto and nothing. just the same knocking sound once per trigger pull.

I pressed the forward assist and then it started to fire again but only for a couple of shots. Pressed the forward assist again but nothing this time. When I cracked it open I saw that the first tooth on my cylinder is getting very worn and there are metal shavings inside the gear box. I took it all apart and cleaned it up and greased it again. Put al the gears back together and it works fine for now.

But why is my piston tooth getting so worn? It is the ICS aluminum piston. The tooth is starting to look like a "U" instead of a block......any ideas???

[Skruface]

Possibilities include bad gears, worn bushings (allowing the gears to wobble, and as the gear wobbles the edges get slightly raised), bad shimming (gears not centered in the piston tooth bed), bad angle on engagement (although this usually only wear the fattest tooth on the piston at the back; the pick-up tooth), not a strong enough spring for your ROF (piston is not returning to battery fast enough after firing, and the gears are catching it moving in the opposite direction before it is fully returned).

Also if you have steel gears and an aluminum piston, of course the piston will wear first.

I will assume that you already know that pistons are designed to be a consumable part (to wear out over time), as they are the least expensive part to replace. This is why every AEG manufacturer sells replacement pistons...they aren't meant to last forever. A decent plastic/nylon/polycarbonate piston is much better for your gearbox in the long run. Most of my guns are highly upgraded, and I prefer to use plain old TM nylon pistons with some slight modification.

If you don't know what you're doing, get your gun to a gun doc. Trust me, the ~$40 he might charge you to replace a piston may seem like a lot of money, nut it's far less than buying 2 or 3 replacement pistons because you screw up the job not knowing exactly what you're doing.

[Schwag]

Skruface covered it all except...Deepfire all-Titanium tooth pistons.
The only good product deepfire makes. It has made the piston a non-consumable part.
Both my guns run fast and strong on lipo and I have had these pistons in for 3 years with barely a scratch.
The only piston I'll use. Can't say enough about them. Worth every penny.

[georche]

Thanks guys. I contacted a gun doc to check the shimming and check everything else. Gonna get a Deepfire all Titanium toothed piston too.