King Arms dragunov Upgardes

[jiffk]

The only posts about this are long dead and links are buried even deeper!

I understand these come with a TB as stock so upgraded barrels aren't common or necessarily needed.

But spring wise, hopup and piston i cant find a lot.

The king arms website talks of a spring upgrade to take it up to around 490fps but theres nowhere that specifically stocks it, is this just an m130-140 spring?