Going to jump in here. Static weight is not the sole factor of a swingweight. How that weight is distributed in a racquet will affect swingweight much more. Racquets that have more mass in the head will have a higher swingweight. Take the Gamma Big Bubba. It weighs 10.4 oz strung (295g) but has a swingweight of 412. The Pro Staff 90 weighs 12.6 oz (357g) but has a swingweight of 327.