Has anyone out there ever gone the the creek bottom, picked out a small bucketful of the finest offerings for slinging and taken them home to put in the rock tumbler for a couple weeks???

The rockhounds and lapidary nuts usually have lots of samples around it it seems to me that the polishing would/could only improve the flight characteristics.  If I had to compete in a distance competition with "prospected"  (as opposed to poured) ammo I would definately polish... but any actual experience...???

The dimples on golf balls set up a scream coming off my sling akin to a sharp cornered stone and describe a curved flight any professional baseball picture would be proud to own but probably never able to control...   I do NOT believe golf balls are designed to fly far and straight IF they have a high rate of rotation in flight... I cannot suoort any other conclusion based on the way they come off my sling with my thrrowing style.


...come to think of it the curve direction (the plane the curve lies in) of a golfball should tell me the orientation of the patch at release which should in turn indicate if my technique will support a football-shaped gland being able to come off into a spiral of the gland.  I gotta go try this...  back later.

GunsOnWheels,
   Golf balls will fly far and straight, IF they have a backspin that is dead-on vertical.  A golf club naturally imparts a backspin to the ball, but getting it precisely vertical is the difference between Jack Nicklaus and ... well, me.  I have sliced a ball so severely, that it nearly took the nose off the guy five lanes to my right at the driving range.  My ball's backspin was so far off vertical, it was a sidespin!

Once you change material all bets are off. In firearms you'd say that the steel ball has a different ballistic coefficient - although it is the same shape, it is much heavier relative to it's projected area/surface area than the golf ball. If you think of it in terms of momentum, it has a higher tendency to keep going straight, while the sideways forces are the same, or smaller.

A better test would be to either fill the dimples in (autobody putty?) or sand them smooth, which will change the diameter but not by too much. For the best comparison you'd like to get the ball as close to polished as possible. I don't think anyone (here) has done this, but if someone does, make sure to post the qualitative results - one more data point for my collection. Separating the magnus effects from the boundary layer transition effects is tough in practice, but the smooth ball should travel a shorter distance.

If I throw underhand/sidearm, a golfball veers down and right, with a vengeance.

I'm not sure what grip you are using, but an interesting experiment is to reverse the spin on the ball by switching which is the trailing cord. With most grips, the release cord is held "on top" of the fist, while the retention side goes somewhere between the fingers, or pinched with the release in a narrow grip. For a right-hander this normally leads to top/clockwise spin. If instead you run the retension cord up through your fist and out the gap at the base of your thumbe and forefinger you can reverse the rollout direction without changing your throw.

Matthias

I appreciate being made aware of the above... it sounds like if someone really wanted to quantitatively measure all of this they would have to develop a mechanical "slinger" where the variables could be fairly precisely controlled and once set, repeat within a small deviation... how "precise" and how "small a deviation" probably TBD.  Seems like if one could develop such a "slinger" and then use ammunition which is loaded with multi-color LED's, shot at dusk and video'd at 30 to 40 thousand frames a second (so one could observe the rotation speed and direction)... aw heck... I'm not sure I want to know that badly.  If I had all the resources available I did before I retired then we could have a go at it but not now.  It would make an interesting test setup and wonderful data ciphering  opportunity though.

Thanks again