Howdy, nothing too crazy but whipped up a few of these and thought I'd share.

Great for tweaking one's spin efforts and really makes a difference when you hit it right - the shot takes right off.

Warning, danger of breaking glass is higher than with a regular tennis ball! They can also take off in somewhat unpredictable arcs depending.

Just make a few slits end to end, stopping short of the axis, fold the ends under and tie with thin cord. I made small notches to keep the cord in place better.

threw some today.
some have irregular shape because the cuts were irregular(broken tennis balls). so they don't fly very straight.

very good for rifle spin practice, not as good as simple tennis balls for accuracy practice.