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View Full Version : Systema cylinder kit-silent head quirk



NMDA
03-12-2009, 04:45 PM
The parts were purchased from airsoftgi. The kit was a non-bore up systema cylinder, cylinder head, and piston kit for a M4. The parts are being installed into a classic army M4.

I bought a systema cylinder and silent piston head kit a few days ago and decided to put it together today. Everything was going fine until I actually tried to push the piston (with silent head attached) into the cylinder; the piston head appears to be too large. Now the piston head will fit into the cylinder without an oring on it, but it requires a lot of force to push it in and pull it out. If the oring that came with the kit is on the piston head, it basically will not fit into the cylinder without sheering off pieces of the oring; pulling it out is basically impossible and I had to remove the cylinder head and push it out through the front.

After encountering this problem I decided to try my stock classic army piston head and piston in the systema cylinder and cylinder head, and it works fairly well. The compression was poor at first, but I swapped the classic army piston oring, which is smaller than the systema oring, for the systema oring and now I have decent compression using the systema cylinder -- systema cylinder head -- systema oring -- classic army piston head -- classic army piston configuration.

I then decided to try the systema silent head in the classic army cylinder. As it turns out the silent piston head will fit into the classic army cylinder with the systema oring on it. It appears that the classic army cylinder and cylinder head are both slightly larger than the systema cylinder and cylinder head. I then tried the configuration with both the classic army cylinder head and the systema cylinder head to compare the compression. As it turns out the configuration with the classic army cylinder head gets better compression than the configuration with the systema cylinder head, but I do not believe that I can use the silent piston head with the standard flat cylinder head (classic army).

So my questions are:
1) Has anyone else had this problem or heard of it? The whole systema cylinder, cylinder head, and silent piston head all came in the same kit, so I expected them to work together.
2) Will the systema cylinder -- systema cylinder head (designed for the silent piston head) -- systema oring -- classic army piston head work well? Specifically the meshing of a flat polycarb piston head with a cylinder head designed for a silent piston head? I suppose the only way to really know would be to put the whole gun back together and try it out.
3) Or should I just not bother with a franken piston-cylinder assembly and just stick with my stock classic army set up?
4) Any suggestions for my situation?

Lastly, I may just refrain from putting the gear box back together until I can get my hands on some calipers and determine the actual size of the systema cylinder and cylinder head; if I am able to do this I will post the outcome in a few days. Sorry for the long thread, but I thought I would put down all I have come across today so far.