USA bowler
I will have to disagree with you about your comments on gravity and axis rotation. You said " With a 15 lb ball, you cut the axis of rotation down and leave yourself more room to work with. See, gravity forces the differential to the front of the core, increasing over all power and therefore, clearing those nasty corner pins! Works all the time, if you use 16 lbs, you might want to go to 15"
That is not the case at all. 15lb and 16lb balls share the same coverstock and shell so how can it change? The only thing that can make the axis change is the bowlers release and depending on the strength of the bowler that shouldn't change just because the ball is 1 pound heavier. The true difference between the 2 weights is deflection through the pindeck but again that is dependant on bowler speed, revs and strength. PIN placement and the position of the mass bias is the only thing that truly matters with bowling balls.
There are so many variable's involved it isn't funny but in summary my point is that 1 pound difference in weight will not change a bowlers axis tilt or rotation at all. It's all about the PIN and MASS BIAS.
George