[Goge]

Originally Posted by CDN_Stalker

PDI springs are crap, they have such bad consistancies from spring to spring (and Im talking about the same rating)................... I've had a handfull PDI 150% springs come across my bench, and they've been from 350fps to 425fps (and a pain to install), and different lengths too. The 350fps one I have is 6 3/8" long, most of the others were closer to 7", and had one that was right on 7" long. Nutshell, scrap that spring (any PDI spring is garbage that'll end up wrecking your gun), buy a Modify 90 from airsoftparts, install and have fun playing. That spring should keep you under 350fps (considering the long barrel in it), it nets me around 330fps in one of my MP5s.

That was the advice I was given and Stalker is a knowledgeable guy so I'd trust what he says.