jg hk416

[Ponche]

i'm havin an issue with my gun,here it goes.
i put a 130 spring in and it shoot like 310fps.all the gears look great,no waer on them from what i can see.the piston,cilonder and the hoppup all look good.the barrel is all nice and clean.
any idea's on what i could try??

[Whiskey]

check your compression. sounds like there is none. Good places to check would be piston head>cylinder seal, cylinder head>cylinder seal, air nozzle>cylinder head seal and air nozzle>hopup seal you could have compression losses in all of these areas or just one major leak, i'd check your piston head O-ring first as that is likley the problem. What brand is the 130 spring you are using?, Some manufactures have been known for loose tolerences on there spring ratings *cough* guarder *cough*, or it could be a totally different rate of spring mispackaged from the factory.

[Ponche]

it's a gaurder spring.i have check the compression,it seems to be good.lots of air flow come out.
piston head and cilinder look great,also doesn't seem to have any leaks.
so you thinkin that the spring might be a bad spring?

[Boyso]

Take out all the compression components from your gearbox

Piston w/head
Cylinder w/head
Tappet Plate
Nozzle

Assemble everything, hold the tappet plate with your right hand and block the nozzle with your right thumb (try to keep the nozzle 1 or 2mm away from the cylinder head)

Then, push the piston in the cylinder. It should go over the port and stop right there.

If you can still push the piston, or you hear air hissing. You're losing air.

You might want to strech your piston head oring if it's the case.


What was your previous spring and FPS?

[Ponche]

it was a 120 guarder.it wa shootin about 350 with .25's.but wheen i took it out it was shoootin 290 with .25's.that spring was f-cked when i took it out.

[Spawn28]

Compression is good no leaks. Plugged the nozzel and pushed the piston and it wont move till i release the nozzel allowing air to flow.

Yes 2 of us are scratchin our heads on this one

[Boyso]

What about Nozzle to bucking?

I just don't get how it can be happening if you haven't changed anything.

Maybe check if nozzle, hop up and bucking aren't damaged.

[Ponche]

is it posible that the spring might be a dud??
like i said everything looks good no damage that we can see.

[Boyso]

Could be. Try with another brand.

When you chrono it, also check the consistency. Like the FPS deviation.

If there's next to no FPS deviation, most likely the spring.

If the FPS jumps from one end to another, something else, hehe :P

[AngelusNex]

May have been incorrectly packaged spring (ie. 90 spring in 120 package)

[Ponche]

well i think i'm leanin towards the spring,cause it close to the same fps with in like 10fps

[LocoYokoPoco]

Another thing, depending on what gun you have, the spring that pushes the hopup unit can make a huge difference in velocity if you are missing it.

http://www.landwarriorairsoft.com/ac...ullhop_ass.gif
(Top right spring)

[Ponche]

when i bought this gun that spring was missin and it was still shooting 400 out of the box.it has been replaced since,but it didn't make a difference.