Dboys 416 w/Dboys gearbox, Compression issues?
 

I am stumped on this one. I have checked compression with the piston, cylinder and cylinder head, and nozzle together, and I get a LOT of resistance putting the piston all the way in.
Piston stops moving almost immediately. So I assume, I am getting great compression.
I have o-rings in front of the hopup, so it can seat itself better against the gearbox.
Once everything is assembled, and test fired, BBs only fly 20 feet.
Heres what I am using:
SHS nozzle with oring
SHS one piece cylinder/cylinder head
Modify aluminum piston head w/ new Oring
Modify hopup, with modify flathop bucking
Stock barrell
Also, have a delayer chip installed on the gears.
I'm starting to suspect I may need a new cylinder and cylinder head,
as the nozzle does not slide freely on the cylinder head. there's some resistance.
Maybe even a new tappet plate?
Maybe the parts all just don't mesh well with the dboys body, somethings out of alignment?
http://i1284.photobucket.com/albums/...pshuslywc8.jpg

Take the barrel group out and try pushing a BB through the hop rubber's seal, should take much more than the weight of a pen to push it through.

Hop should be slightly on

Look down the barrel and check your air nozzle alignment

air nozzle seal test, with the air nozzle fully forward shine a light up the mag well and see if there's any light in the barrel

air nozzle should move freely on the cylinder head, but keep in mind there's an O-ring on it, too

what kinds of BBS?

What gears and spring are you using? Any short stroking?

Did you do the compression test with the tappet plate installed?

If you did everything right the usual culprits are usually the nozzle (length if it's too short but usually not a problem in your case if it feeds), hop up unit (bucking, arm, nubs, etc).

Any broken bb's when you're shooting?

Haven't tried any remedies yet. In the meantime :
I am using airsoft logic .25
And the gears are shs 18:1 gears with a shs metal delayer switch.
Gears are not short stroked.
Compression test was done with tappet plate. Tappet plate is even sanded down.
Spring is a big dragon M100.
Don't know the fps of my gun, waiting for my chronograph to come in.

For the air nozzle test "shining a light down the barrell". I'm assuming its not a good thing if I see light?

make sure the air nozzle is in the full forward position when you shine a light up into the hop chamber, but no, you shouldn't be able to see any light looking down the barrel.