Prometheus Spring installation

[Crunchmeister]

Is there any particular way that you have to stretch them? Some trick, or something to avoid perhaps? I'd hate to break my o-ring.

[ILLusion]

It basically involves taking one edge of the oring up and "rolling" it above and on to the face of the piston head. Carry that rolling method all the way around the entire circumference so that the whole o-ring gets an even stretch all around.

This would be a good time to remove the entire o-ring to give it a very light greasing with cylinder grease.

[SN1P3R 808]

Originally Posted by Crunchmeister

That's what I suspect. I had really good compression when holding my finger on the nozzle and pushing the piston. But because I didn't know I had to stretch the Systema piston head o-ring, I reused the stock CA one. That may be the problem. I'll be fixing that once I receive my new parts.

But even as it is now, 350 fps isn't bad. It's a nice improvement over the stock 300-ish performance. But it should be more than that.

I just bought a CA MP5A3 and didn't even shot one bb out of it. I just open up the mechbox and did the mods.

I got

1 x Prometheus Non-Liner Spring MS 100 SP
1 x Systema Hop Up Bucking
1 x Prometheus 6.03 EG Barrel 229 mm
1 x Area 1000 Piston Head
1 x Prometheus 6mm Bearing Axle Hole
1 x King Arms Tappet Plate for Ver.2 Gearbox (Red)
1 x Prometheus Selector Plate For MP5 Series (Red)
1 x Systema Metal Shim Set
1 x Area 1000 Poly Carbonate Piston for Ver 2/3

When I put the New pistion in the cylinder and check for compression it was not good. I also had to use the CA o-ring on the new pistion head. CA o-ring is a little bigger. I think I have to use a new cylinder to use any other brand pistion head.

[CDN_Stalker]

Originally Posted by Crunchmeister

Is there any particular way that you have to stretch them? Some trick, or something to avoid perhaps? I'd hate to break my o-ring.

I've just been putting a bit of silly oil or grease on the O-ring, pushing it to one side to be able to get a small jewellers screwdriver under the O-ring, then gently circle the piston head with the screwdriver stretching the O-ring on all sides.

[Crunchmeister]

Thanks for the info on the stretching, guys. I appreciate the input. I can always count on you guys for solid advice. Once I get my new parts and get them installed and stretched the o-ring, I'll post the results.