Yes, I believe I just got lucky. When I bought the Vulcan, we rigged it up with a 355 grain arrow which we weighed on the digital scale. After 3 shots through the chronograph, we averaged 328.6 fps....I then shot my 390 grain CX arrows and they registered 314 fps 3 x's in a row. Thats when I went with the heavier arrow in the FMJ Axis 340 which grain 450 grains. These registered 297 fps 3 shots in a row. To verify these speeds, I took my bow to another bow shop and record 1 fps faster with the different chronograph.