Unless your airsoft gun is using a version 2 mechbox, do not install a Guarder polycarbonate piston head! Not knowing any better I replaced my broken M14 piston head with another Guarder polycarbonate, since I had an extra and it’s a good thing I checked the mechbox before this weekend’s field game.
That was only after ~100 rounds of test firing! As you can see there’s a small crack near the top three holes similar in what happened to my P90 piston head, although not as far developed.
In case you’re wondering what my M14 setup is, I’m using a Guarder SP110 spring (with a few coils cut off so it fires 400 fps), a Guarder spring guide, the stock cylinder and stock cylinder head. Nothing special and stress from the SP110 should be consider moderate. Heh if you’re wondering about my competency, the only part I’ve had a problem with is the Guarder polycarbonate piston head. That and I’ve worked on 10 AEGs so far this year. 😉
MadMax of ASC Armoury posted this thread at Airsoft Canada and they’ve confirmed that the Guarder polycarbonate piston head is weak and prone to breaking. 🙁 They have since pulled the product from their shelves (kudos to you guys for not selling them anymore!) but you should keep this in mind if you deal with other retailers! It would suck if your piston head shatters while playing a game like mine did a few weeks ago.
I’m happy to report that the M14 piston head was replaced with a Guarder aluminum model and the gun is firing nicely. Heh the aluminum piston head will not break but it adds stress to a mechbox. Knowing my luck, I’ll be the first person in the world to break a version 7 mechbox…