Telling the difference between a pre system 7 USP and a system 7 USP?

[Coski]

Any help here guys? Looking at getting a KWA USP in a swap deal, but neither I or the seller is sure if it is system 7 or not.

[voodooTheMarshmallow]

Re: Telling the difference between a pre system 7 USP and a system 7 USP?

I believe the gas release valve on the bag of the mag and the rubber seal at the top are different , I think KWA or KSC put out a video on how to tell the difference a while ago.

[sparrowhawk]

Re: Telling the difference between a pre system 7 USP and a system 7 USP?

easiest way is to remove the slide pull back the blowback chamber and check the colour of the piston cup, i cant remember what colour its supposed to be though....

[sonicninja]

Can you upload a picture of the mag? Ideally a side of picture.