Round Ball in shotgun question

[PPpastordon]

When watching a PBS program recently they talked about how the dimples on a golf ball caused two things. They fly straighter and farther than smooth ones.
QUESTION: Would dimpling a lead round ball do the same when fired in a shot cup from a shotgun? The cup would prevent any spin to cause it to go right or left. The dimples should provide the lift as it does (according to them) on a golf ball.
In short, the ball should fly straighter and farther. They said a smooth golf ball flew only a little over half as far as the dimpled one. That is a big, big difference!
If these could be cast, say, from WW, this could possibly rival the saboted slugs from a rifled barrel and at a much cheaper cost! 20 Ga., about 350 g and a 12 Ga., about 580 g.
Whatcha think?

[45 2.1]

The blackpowder guys use a modification of that. That roll the ball between a piece of soft wood and a rasp to raise "stipling" all over the surface with good results claimed.

[krag35]

I ran some 58 cal RB thru my vibrating tumbler, can't say they flew any farther, but I did find some voids I didn't know was there. I'm sold, I'll "tumble" all my RB from now on.

[Duckiller]

Long ago and far away I took a class in fluid mechanics( air is a thin fluid). During the class dimples in golf balls were discussed. USGA controls the depth of dimples. Too deep and a weekend hacker can outdrive the best pro. All this is a result of, I believe, Froude's number. The dimples reduce the drag on the spherical surface and lets the object travel faster/farther. Golf balls and round ball boolits are all the same to a student of fluid mechanics. Biggest problem is getting uniform dimples of consistant depth. Individual golfers can only hit the ball just so hard. Individual shooter can stuff more powder under their boolits. Duckiller CA RCE 20955

[KCSO]

Go one better, a ball with circular grooves was made a few years back and you couldn't slice it. It always went straight. But then again our ancestors solved that problem by going to a BULLET.

[PPpastordon]

I wish to thank everyone for their shared information and comments. From this end, the experimentation is going on. I, or my associate in this "quest" (he lurks here) will let all y'all know of our results as/when they develop.

BTW; 45 2.1, Love that signature. Much like one I once had on my wall - but, I believe, dealing only with knowledge.

[twotoescharlie]

been loading round ball in shotgun shells for years, sure do make a racket when that big ol' ball hits something.

TTC

[randyrat]

One little problem with your idea...Blowby... You may have something, but, blowby may be aproblem

[randyrat]

been loading round ball in shotgun shells for years, sure do make a racket when that big ol' ball hits something.

TTC

How do you do that? What are your loads? very interesting

[randyrat]

One little problem with your idea...Blowby... You may have something, but, blowby may be aproblem

Opps i doubt there's any problem with blowby if it's in a wad.

[357maximum]

For those who are new to venturing into the RB shotgun arena,,I suggest you get your mits on a copy of Lyman shotshell handbook 3rd edition, priceless data there... the 20 gauge loads using .575 rd's and a shotcup, are quite deadly through the average smoothbore... My buddy has used my #1 handload ( bottom load on pg. 276) to harvest several nice michigan whitetail at distance up to and beyond 100 yards. They work awesome out of his old 870 with a saddle mounted 4X weaver....made my fully rifled barrelled high dollar sabots look a bit sad. I have since sold the fr barrel and went to a single shot win mod. 37a with an weaver encore mount and a straight 6 leoupold....accuracy is sweet.. and one of these years I will kill my buck with MY RB handloads....too enamored with the peestol right now...

My lead RB loads are made of air cooled ww , BTW

Federal rheifenhauser case
25.0gr 800X
win 209 primer
one fed 20s1)(old style stiff wad)
1- 1/2 in (28 ga)fiber under ball
fold or roll crimp ( I use folded crimp)
Book= 1650 fps........actual for our guns= 1670+
all balls are lightly coated in motor mica for a smoother release from wad(in theory anyway)


Michael

[bruce drake]

"My balls are made of air cooled ww , BTW"

I'm not even touching that comment with a 10ft pole!

[357maximum]

"My balls are made of air cooled ww , BTW"

I'm not even touching that comment with a 10ft pole!

Kinda left myself open for that one....har D har har

[Greg5278]

Round balls in a 12 gauge is nothing new. You can use .662. .678. and .690 balls in suitable wads. The smaller sizes work better, because the wad is less likely to shear off on one side. The .690, an .715" balls can be wrapped in Teflon Sheet.

I seem to recall an article in Handloader magazine in the 70s about rounds balls in shotguns. They mentioned one load with a .662 ball, that was going 1626FPS, and grouping in 2" at 100 yards.

I haven't fired any that tight, but It shows it can be done.
Greg

[leftiye]

Does this mean that a rough projectile will create less turbulence than a smooth one? I thaynk ay'll stick to conicals in a rifled shotgun thank you. Nasty stuff!

[floodgate]

leftiye:

As I heard it, the dimples give little swirls of "micro-turbulence" that pretty well balance out over the whole ball, while a smooth sphere builds up bigger swirls that - when they break off the ball - kick it off course one way or another, in unpredictable fashion. The "pibals" - "pilot balloons" 3 - 9 ft. diameter - used for gauging wind velocity vs. altitude would skate back and forth several feet in still air, while rising. Back in the early '60's, someone tride gluing a couple dozen conical "Dixie Cups" to a pibal and released it alongside a normal one in still air - I think it was in an old WWII blimp hangar - the plain pibal skated back and forth as it rose to the ceiling; the "decorated" one went pretty near straight up. This is, of course, the opposite of dimples, but I think the principle is the same. All bets are off, too, if the ball is spinning (from a rifled barrel) or tumbling (from too much "windage" in a smoothbore). All this is from some dim memories from back when I worked with a bunch of meteorologists; I'm sure a lot more is known about this stuff now.

floodgate

[9.3X62AL]

What complications can occur by firing these RB's through choked barrels? Is cylinder bore best? I know Foster slugs do their best in improved cylinder or skeet chokes. My main concern is the RB hitting the cone portion of the choke off-center--or potential damage by the oversize ball--or distending the parallel sides--or some combination of these. Any experience to fall back on here?

[grumpy one]

leftiye:

As I heard it, the dimples give little swirls of "micro-turbulence" that pretty well balance out over the whole ball, while a smooth sphere builds up bigger swirls that - when they break off the ball - kick it off course one way or another, in unpredictable fashion. The "pibals" - "pilot balloons" 3 - 9 ft. diameter - used for gauging wind velocity vs. altitude would skate back and forth several feet in still air, while rising. Back in the early '60's, someone tride gluing a couple dozen conical "Dixie Cups" to a pibal and released it alongside a normal one in still air - I think it was in an old WWII blimp hangar - the plain pibal skated back and forth as it rose to the ceiling; the "decorated" one went pretty near straight up. This is, of course, the opposite of dimples, but I think the principle is the same. All bets are off, too, if the ball is spinning (from a rifled barrel) or tumbling (from too much "windage" in a smoothbore). All this is from some dim memories from back when I worked with a bunch of meteorologists; I'm sure a lot more is known about this stuff now.

floodgate

Doug, there is a classic aerodynamics experiment that involves comparing the drag coefficients of a golf ball and a smooth ball of the same size. If you plot drag coefficient versus Reynolds number (a dimensionless number related to fluid velocity) there is a fairly small (when shown on the usual log scale) range where the dimpled ball has measurably lower drag than the smooth ball. Outside that range, the dimpled ball has higher drag. The important part of the range for a golf ball propelled by a driver coincides fairly well with the lower drag region.

In WW II there was a Handley-Page two seater that had a pair of machine guns operated from the rear cockpit. Of course when the guns were swung around to nail somebody beside you, the aircraft slowed down so often you didn't get your shot. Some aerodynamics boffins calculated that the problem would be lessened if the air cooling jackets on the guns were INCREASED in diameter by an eighth of an inch, and begorrah, it worked! Just needed a slightly higher Reynolds number to get into the zone.

I would be surprised if any sensible bullet projected by anything more convincing than a paintball gun was in the critical range of Reynolds numbers to gain any advantage from surface roughness. Remember that outside the critical zone, roughness creates more drag, not less.

Geoff

[floodgate]

Geoff:

I'm sure you're right; but they did start moulding the pibals out of mylar with "cups" on them - looked like a WWI mine. One of our contractors for weather work had a pair of Cessna 206's - big single-engine six-placers - that came off the production line only a couple of serial numbers apart. One was about three knots faster than the other at any specified rpm and throttle setting; faster, that is, until the "slow" one went through a hailstorm and came out looking like it had been worked over by angry elves with little 4-oz. ball-peen hammers. Thereafter, it was the faster of the two by a couple of knots. A soaring enthusiast friend always went over a new paint job on his glider with 150-grit wet-or-dry sandpaper to roughen up the skin just enough to break up and delay flow separation on the wings. And we've heard here about the "too-smooth" ML barrels. Yes, this is all anecdotal, but hmmm....

floodgate

[grumpy one]

Your balloons would have travelled at fairly low speed, I think. The advantage to roughness happens in a speed zone where "flow separation" is just about to occur, and by making a turbulent boundary layer instead of a laminar boundary layer it causes the boundary layer to adhere to the parent body - turbulent boundary layers are "sticky". However once you get to a point well beyond where even a turbulent boundary layer will have separated, roughness is unhelpful. In the 1950s the English Electric Canberra - a twin jet engined light bomber which was the basis for the Martin B57 - was made in large numbers in the UK and in very small numbers in Australia. The Australian approach of course was a sort of row of craftsmen hammering them out on their tiny forges. The aircraft were nominally identical including engines etc, but the Australian-made ones were 20 knots faster. This is traditionally attributed to the craftsman approach, which resulted in very smooth curves over the wings rather than the usual rag-tag look you can see any time you peer through the window of a commercial aircraft.