Spring choice for V2.5 gearbox

[snowy70838]

I have modified a G&G SR25 to take a version 2.5 gearbox.

 

Does anyone have experience with spring choice for these gearboxes? I am after 400 to 425fps.

 

The barrel is a 509 x 6.03mm madbull.

 

Thanks

[M_P]

What is a version 2.5?

[sp00n]

There is a list on airsoft sniper forum, under long range AEG section

[sp00n]

What is a version 2.5?

Apparently it's a long version 2 gearbox (longer cylinder and piston etc), mainly in sr-25's from what I have read

[snowy70838]

G&G SR25's come fitted with a standard version 2 gearbox. I modified mine to take a version 2.5. After the effort involved in getting it to fit I wouldn't do it again.

 

The version 2.5 is just a longer version 2. The extra length being the longer piston and cylinder.

 

Take a look here....

 

http://forums.6mmdistrict.com/showthread.php?tid=1980

[snowy70838]

There is a list on airsoft sniper forum, under long range AEG section

 

Thanks

[sp00n]

just out of interest has the gearbox made a massive difference?

[snowy70838]

Yes. The range has increased dramatically and it is only pushing out at 360fps at the moment. Using 0.36bb

 

I should say it's pushing out 360fps using 0.2g bbs but i actually use 0.36g bbs for test shooting.

[M_P]

I don't see how the type if gearbox has any relevance in increasing the range. That's all to do with the power, hop and barrel.

[snowy70838]

It is something to do with the cylinder to barrel volume ratio being better for long barrels. As the V2.5 has a longer cylinder/piston than a V2.

 

I dont understand this myself but all i can say is it works.