Drilled my GB4 40x4.75x40: identical to my Omni which is the best ball I have thrown in the past 5 years. The Omni gives me a very Black Widow like ball shape - sufficient traction on medium/heavy oil with a big round arc that keeps coming on the back end. My hope was for the GB4 to give me an option to ball down to when I want to flatten out my angles.
I threw 2 shots with the GB4 before turning the camera on to record my video ball review:
https://www.youtube.com/watch?v=fvaDeB9wWO8&t=344sOut of the box the GB4 was just an absolute monster. 500/1500 grit is a LOT of cover and actually had me deeper than the Omni in order to get the ball down the lane. The softer shape off the friction was good, but I didn't need a symmetric to be that strong when I already have the Omni and the Zeniths.
What didn't make the video was my surface adjustment in hitting the GB4 with a 3k pad. This smoother finish gave me a drastically different ball reaction in which I was able to move 5 boards right with my feet yet still get the ball to the same break point. The GB4 at 3k was much cleaner through the front and allowed me to keep my hand further behind the ball to play closer to the track which is exactly what I needed to score on fresh lanes. As fun as it was to wheel the GB4 through the middle of the lane, this finish is much more playable and makes the ball a viable option a wider range of patterns.
Compared to other balls in my bag, the GB4 slots somewhere between my Hero Solid and Knockout. The Hero Solid is a little earlier/flatter than the GB4 which works better on shorter patterns, while the Knockout gets further down the lane and sees the corner a little bit more.
The GB4 with the surface change has me 4/2 right of the Omni with a smoother motion off of the dry boards. I find that these 2 balls really compliment each other well and can see myself bringing these balls to tournaments instead of the Hero/Knockout.