Spring Issue

HarryHirsch

I have a spring problem. I have a AUG and I had put in a tight bore barrel. After installing the barrel the fps rised up to 345. So i decided to use another spring. First I tried a Element MS95 but the fps were too high. So I finally bought a Prometheus non linear spring MS90. Now I have the probem that I have only 250 fps.:( First I thought, that it might be a air leaking problem. So i checked the pistonhead, o-ring, cylinder and nozzle, but I couldn*t find anything. What can I do to find the Problem?

The only good thihng is that I got a certain routine with V3 gearboxes. The trigger is a nasty thing ;-).

conor-mr2

Revert back to the other spring to see if the FPS goes back up again. If it does and that is the only thing you have changed then you know its the spring.
A helping of grease on the O-ring and piston is useful. Some grease behind the air nozzle where it slides onto the cylinder head.

Alas there are lots of variables involved and you need to change one at a time and retest. It can be frustrating disassembling and reassembling that gearbox.

kdouglas

Not too much grease though, otherwise you'll just end up with grease all over the inside of your hopup unit and barrel as it gets expelled from the gearbox.

Masada

yeah id say its an airleak of some sort., most likely on the piston ring itself., either that or the hopup has an air leak.,

HarryHirsch

I found out, that the hop up, was on full position. Now with no hopup its between 280 and 300 fps. Is this normal ? Maybe is a little bit less when the hop up is used. Shouldn't it be more, like 320?

conor-mr2

An ms90 spring, hop up off and around 300fps. Sounds about rite for the spring type.

As a comparison Ive got a CA G36c, v3 mechbox aswell. I stuck a m100 spring in it last nite and it shoots at 320-ish fps. Ive a guarder hop up on it and yes the adjustment on the hop up will make a difference to fps--resistance.

HarryHirsch

Ehobby Asia offers the Spting for an upgrade to 330-340 fps ([URL="ttp://cgi.ebay.com/Prometheus-Non-Linear-Airsoft-340FPS-Spring-MS90-FS4_W0QQitemZ270277318009QQihZ017QQcategoryZ31681QQtcZphotoQQcmdZViewItemQQ_trksidZp1742.m153.l1262"]Prometheus MS90 Spring at Ehobby Asia[/URL])

But if MS90 means 90 m/s = 295.20 fps =0.81 J (with 0.2 g BBs) It should be ok
Then is Ehobby Asia scamming his customers.

Does anyone got one of these springs from Eiresoft (the same Prometheus MS 90 spring from Eirsoft) But there its offered as 300 fps upgrade.

Stercus Accidit

Barrel diameter, length, hop type, gear box type, cylinder head type, piston head type all affect fps.

Spring is a factor, it isnt the only one.

Masada

In an AUG, (Version 3 gearbox) the Promethius MS90 will give you about 320-325 fps.