"simple" spring length question

[Omnivorous]

I feel like this is a newbie question...

Why do certain AEGs use slightly shorter springs, and even more important, why aren't they available for purchase anywhere?!!?

Typical spring length - 7"

Spring length in certain guns - 6.5"

I searched for a thread talking about this but couldn't find it.

I know you can clip springs, but it's obnoxious experimenting until you get the correct fps, and if you clip too much ... wasted $$$.

I feel like I must be missing something... So far I've seen an ICS M4, a Classic Army P90, and even the VFC Virtus uses these shorter springs.

Thanks!!

[venture]

Hi. The shorter springs are just stiffer. The longer ones will still fit.

[Ratters]

hey, refrain from clipping because you don't want a short spring flopping around inside your gearbox during firing

a quick change style gearbox won't indicate this but a standard gearbox rebuild would show the spring is going in and not under tension bad bad bad

The other risk is completely shearing off piston and gear teeth

Take the time, swear, grunt and groan and fight the fight stuffing that spring back in without having the box explode with all the parts shooting across the room

ask for help and a second pair of hands if they're around and yeah, your hands will sweat the first time and you'll swear like a new sailor finding the last apple at the bottom of a barrel on a moonlit night while a salty old dog finds true love

If you tear down the gearbox use a ball-bearing spring guide and piston head to help the spring torque correctly and make sure you shim it right

If your careful and do a good job that gun will run smooth and be a faithful go to for a long long time