TKOverKill

In Japan we have low 0.98J requirements however we still like to put in Lipos into our setups. When RoF goes up even if we get the right AoE we can piston breakages (not wear; but the breaking of the pickup engagement tooth). The goal is to get the piston return, before the sector gear picks up the 1st (or last depending on perspective) pickup tooth on the piston.

Most pistons we can buy in the shops are somewhat heavy (Prometheus, Supercore, even TM's stock piston). So swiss cheesing to lighten the piston is quite common with higher RoFs + low J springs.

Here's's some of the weight savings from swiss cheesing a piston :-

1) Super Shooter with a metal pickup tooth (13g -> 9g) :-





2) Element All metal teeth (15/16g -> 11g) :-



Choosing the right piston & deciding how much to swiss cheese is important. If you pick a weak piston (e.g. Systema Polycarb) and over swiss-cheese, it will break on you. Recommendations from Airsoft Mechanics and from my own trials, Super Shooter/SHS/Combat Squad and other Azimuth clones seem to be very durable, and highly swiss cheesable. The Orange Element above hasn't been tested long enough for durability tests.

Note some other brands already sell swiss cheesed pistons (e.g. G&P, Military Action, etc), but they're all metal and are still heavy.

Thanks for the tip Q! ^^

Here's my recent Sopmod piston failure at the just past Desert Union game :-



The wear is at two points :-

1) pickup tooth - that's most likely caused by poor AOE.
[NOTE: 2nd tooth was shaved off on purpose]
2) teeth 8 -> 16 - that's most likely caused by something to cause the piston return slowly. That's either piston weight, or a blocked nozzle/hop chamber/inner barrel. Here the piston takes too long to hit the cylinder head and the sector gear has already completed a full cycle - thereby crashing with the piston in the middle set of the teeth.

So here I bought a Laylax Piston for Sopmod and cut down it's weight from 12g to 7g.




The structural integrity of the piston still seems quite strong despite shedding so much material from it. Sadly, the matching M4 Sopmod piston head is heavy with ridiculous counterweights. I've tried various combinations of screwing in the piston head to the piston but due to the funny design of the inside of the piston, the walls and metal teeth will buckle if I tighten it too much so I do need the silly counter weight to the piston head POM.

It's good that you were able to quantify the results here. I have been doing this for years on my high speed setups.

Did you see Laylax Progress Molibuden Grease? It apparently is some cyldinder spray that helps the piston and O ring seal while being so slick, it greatly reduces friction between piston head and cylinder walls to the point where the piston can speed into battery without resistance.

Also, I know that AOE has picked up alot of institutional inertia over the years. But it seems to place the piston further back and in greater danger of pre engagement. I usually double ramp pick up tooth to spread impact and help the gear meshing.

I usually earthquake cushion my cylinder heads, which does help AOE some but I wonder how much it really helps things.