Works, you just need to swap the O-ring out for the stock O-ring as the ASP piston is slighty smaller.

 

Ok, thank you! Would you know what size was the stock o-ring? I have a couple laying around, but I have no idea which one is which.

 

Would you say it would be worth it throwing in the 30€ for the AA piston to ensure it would be a perfect match with the AA cylinder? *I would probably stand using some of the classic vsr springs, which brings me to another question, which of them would you guys recommend? Thanks.

 

Just get a stock piston and use the O-ring of that. The ASP piston accepts 13 mm springs so that's an advantage of the AA one. If you get the AA piston that'll also work but you're spending more money which isn't really necessary.

 

I would say use the AA one, i myself am using ASP piston in a stock TM cylinder with a bigger O-ring and the quiderings are too narrow to ensure the piston is moving straight. The metalpart of the piston (which grabs the sear) is dragging on the cylinder walls making horrible sound and marks inside the cylinder. You dont want that to happen to your precious teflon cylinder. So yes, in theory it works, but its not perfect.