so a m150 "should" give ya 493fps. But not Guarder as they are often over the spring rating. AEG SVD might only req a m140-ish due to long barrel creep
It's spring powered, but it uses AEG springs. Read a few posts that suggested that the 190% would output near 500 FPS, other posts (like the one you linked) say 400 to 450 FPS. We'll see.