IDk lol. I dont know for sure what the spring was. I didnt build it. I believed it was a 170. But, apparently it was higher. LOL. I was there when we chronoed it. It jumped to a bit over 700 fps and we looked at each other with jaws dropped. We chronoed it several times and got the same result. We had to play with the airbrake to get it down. Bushman does a rainx polish on the inner barrel that seems to increase fps . But, I cant be sure what the spring was. Only what it chronoed.
Youll have to forgive me if I mis-speak. Ive only built a few AEGs never a sniper. Bushman built them, I shot them. LOL