Smooth Bore Ball Prep

[missionary5155]

Good afternoon
Been shooting RB from smooth bores about 30 years. Tried a lot of ideas. Been following many here. But it always came down to maybe gaining 5-10 yards but at the cost of alot of work. So I have been very happy to shoot RB from "smoothies" and just shoot under 50 yards. As I hunt river bottoms and thickets mostly it just does not matter.

The fellers that shoot smoothies with patched RB in competition do all sorts of things of things to get the edge. One is roll the ball between files to roughen the ball exterior. The idea being (as I understand) is the ball is uniformly round plus the "roughened" surface upon leaving the patch should / may start to spin some by air passing over / around it making it a bit more aero-dynamic and fly straight for a longer distance.
Does it work ? Does the rough surface actually cause the ball to spin ? All I know is that the fellers that win shoot a rough surface ball.

So enter www.forth-armoury.com . The feller there has made an easy to use drill press rig to roughen RB. Again will it really make a RB fly straighter ? He shows the File Rig the serious shooters use. Some use smoother files and some use near wood rasps to roughen the RB. Not sure if one is any better... course or smoother. But the roughened ball shooters are generally the winners.

So again I cannot write I have tried it enough to write it really works. Or why it works. But it does something that seems to work and increase accuracy of smooth bore RB shooting.
My solution some years back was to purchase a Rifled 12 bore Pedersoli ML if I thought I needed to punch 12 bore holes in critters beyond 50 yards. That does it easily to 100 yards !
But maybe I need to give roughened RB a better trial. Maybe the 12 bore Fox B double with .005 constriction can accurately launch .685 RB out to 65-70 yards consistently. Maybe farther ??
Mike in Peru

[Markopolo]

Interesting thought... I have no comment, but am subscribing to see what the sluggers say...

Marko

[Hogtamer]

Cannelure the perimeter of the ball?

[Oklahoma Rebel]

well, I have thought of having someone make a mold that casts a rounball with dimples, basically an exact, scaled down golf ball. if you look up, I believe, bernoulli's spl? principle, the way it works is the dimples cause the vortex behind the ball to break up, so there is not as much of a low pressure zone behind it, this reduces drag, and I believe it would relieve that "curveball" effect at longer ranges also, I am just not sure about the logistics of making that mold, and if it can be done with modern CNC's

[FullTang]

Funny you should mention this, because the Duelist just did a video about this on Full30:

https://www.full30.com/video/6a21795...e6bd45152c8610

Personally, I've found that the only way to improve the flight of a round ball is to shoot it through rifling. Everything else seems to be a waste of time, since the axis of rotation is critical.

[missionary5155]

Thank you for posting that link. That is the tool.
As the Duelist stated "Every smooth bore is a gun unto itself".
No idea how much work he has done with that smooth bore so I cannot comment on his accuracy nor loading techniques.
I have found all our smooth bore ML's shoot better with a patched RB. But have not tried "blanket" over the ball. Nor 110 grains 2F with blanket over the ball. But I personally would have to write 10 shots unpatched does not prove or disprove the idea.

The "golf ball" dimple only works with "below the speed of sound" threshold as I understand.

[pashiner]

suppose one were to make a small ball mill, kind of like a miniature concrete mixer with paddles or helical vanes to lift and drop the lead balls, but introduce a couple pounds of steel bb's so that the lead balls get bb sized dimples all over? providing they didn't get smacked out of round, I would think you could get a more or less even pattern of golf ball dimples.

[Cap'n Morgan]

The reason for golf ball dimples was new to me, but a google search provided lots of information. From what I gathered the dimples provides "lift" to the ball due to bottom-spin created by the club "slicing" the ball. The dimples increases the Bernoulli effect which causes a spinning object to curve in the direction of the spin.

This would seem to indicate that dimples would be detrimental to accuracy when shooting round balls from a smooth bore. Once the the ball starts to rotate the dimples would actually amplify this rotation, and since the rotation could occur in any random axis to the ball, accuracy would be blowing in the wind - so to speak.

On the other hand, dimples reduce the drag on a golf ball by half, which is pretty amazing if you ask me. Perhaps a round ball with dimples should only have dimples on the top hemisphere. The dimples would reduce the drag over the front, and once the ball starts to tilt, the increased drag from the smooth bottom hemisphere entering the slipstream would keep the ball from starting to rotate. Of course you wouldn't get the benefit of reduced drag in the ballistic as the golfers get, but wouldn't it be nice if we could keep a subsonic lead ball from picking up a random spin once it gets past 50 yards?

Just thinking out loud here. The idea is probably nuts...

[missionary5155]

Good afternoon
And some not so well meaning people thought the Wright brothers were a bit nuts also ....
Who really knows what idea may just pan out. Look where we are today because individuals decided to give it a try.

[longbow]

Yup! I'm with Cap'n Morgan on the dimples. I don't believe a rough or dimpled ball will fly better than a smooth ball... maybe as well under certain circumstances but I doubt better.

The dimples are on golf balls to create turbulent flow and reduce drag and as Cap'n Morgan says, to provide lift due to the underspin put on the ball by the club.

When you think of spinning balls, think of a curve ball thrown in baseball. That curved flight is induced by the spin the pitcher puts on the ball. I do not want a spin on my balls (now that sort of sounds rude!).

After watching that video I have to say that I was not impressed with his accuracy at all. I do better with my smoothbore cartridge shotgun and from what I have read and been told by some of my friends with smoothbore muskets, they tend to get better accuracy than I do using tightly patch round balls. The goal being no spin on the ball when it leaves the muzzle.

I have found that loose underbore balls shoot very poorly for me where full bore balls or balls loaded snugly into shotcups shoot very well for me and again, those loose balls are free to pick up spin in the bore where the tight balls cannot. That says enough for me.

I will agree that this is my opinion and not proven by me by testing a variety of ball sizes and loads in a scientific manner which is the only way to really work it out to a good degree of certainly.

I certainly can say that loose 0.690" RB's in my smoothbore shoot extremely poorly as they did from my muzzleloading 12 ga. but close fitting balls shoot better than most Foster style slugs I have tried.

To each his own and that is the way it should be. I'll watch and wait and if someone proves me wrong then good on them and I'll admit I was wrong and jump on the rough ball bandwagon. Until then I'll stick with as cast balls.

YMMV

Longbow

[Oklahoma Rebel]

for me, that wasn't even close to dimples, just a rough surface. now, you are right about the lift cause when the ball rotates, I did forget about that, but it does reduce drag, so what about REAL dimples, in a rifled bore, on the front and back, with a rb similar to the tanner roundball mold that has a elongated mid-section? nno spin, and dimples where it matters most, front and back? I doubt I am onto any sort of amazing revelation, but, hey, it might help a little, and shooting is a game in which very,very little can make a big difference. just my thoughts...-Travis

[W.R.Buchanan]

Golf Balls go which ever way they are spinning. (Hook, Slice, Rise and Drop) The dimples exacerbate that effect. They also break up the 'Laminar Layer' on the surface of the ball which effectively makes it smaller, and thus makes it fly farther.

Golf balls are tested by a machine called "Iron Byron" which is a mechanical driver machine which hits the ball with the same force everytime. If the ball flies more than about 325 yards it is rejected and not certified for Tournament Play.

The Slazenger Balls that James Bond used were popular in the 60's and 70's however they were smaller than regulation balls (1.687 / 1 11/16" +/-.005) so they were not allowed in tournament play. They were good for another 25 yards.

Laminar Layer is the layer of fluid that is transitioning between the mass being travelled thru and the object that is traveling. Depending on the surface profile of the object the thickness of the layer will vary. Glass smooth produces a thicker layer than a slightly rougher finish.

Harley Davidson figured this out in the 1960's when trying to get everything they could out of their Flat Head Engines. The common wisdom at the time was to polish the ports to a mirror finish in engines. Harley figured out that a slightly rougher finish (Bead Blasted) produced a thinner laminar Layer in the ports thus increasing the size of the port, thus increasing the amount of flow thru the port, which made more HP!

This technology which Harley foolishly broadcast in Cycle News in 1968!, was quickly picked up by everybody(including me working at Honda Ventura as a mechanic) and bled over immediately into sailboats and the Americas Cup where all the crews were seen sanding the bottoms of their boats as the regatta got started.

Since that time all racing sail boats get the gel coat on their hulls burnished (Roughed up) which effectively reduces the displacement of the hull and thus makes it go faster. On a Mono Hulled boat this can add up to as much as .5 Knots which in the Mono Hull world is like a passing gear.

With all this in mind it should be obvious that an increase in retained velocity would be gained by roughing up the outside of a round ball. However it is not going to affect accuracy one bit and if the ball rotates at all it will in fact decrease accuracy.

Round balls achieve their best accuracy (IE:consistency in flight) when not spinning or more properly when flying like a Knuckle Ball. However anyone who has seen a knuckle ball coming at them knows that the ball wanders back and forth as it flies. With respect to a ball fired from a gun this random variation accounts for a group, as opposed to every one going thru the same hole in the target. One thing that could affect accuracy is velocity, which would cut down on the ball's tendency to "dance" thru the air by shear brute force.

My .02

Randy

[pashiner]

This is getting more scientific than I ever thought smooth bore round ball shooting can get! It sounds like if the roughed surface of the ball contributes to a smaller laminar flow profile, then the "knuckle ball wander" effect may be diminished to the same extent that the drag on the ball is reduced. Keep working on this, guys...you may be breaking new ground in the art of musketry.

[W.R.Buchanan]

pashner: the effects are so small in this case you would never see it.

On a Americas Cup Sailboat different story. Any gain in hull speed is a big deal.

Harley 45's made about 1-2 more HP as a result, and since they told everybody what they did, their advantage was gone in less than two weeks. We blasted our ports in the Triumphs that week and after retuning the Harley guys were watching 12X's rear end again the next Friday night race at Ascot. We got more than 2 hp on the Triumph 500's from that simple mod.

Randy

[pashiner]

Randy,
I think you're probably right about the tiny effect of the rough surface. I re-read your post, and the detrimental "curveball" effect from picking up spin makes sense with a rougher ball. It sounds like the smoother the better in fullbore round balls, because they're likely to get at least a little unwanted spin from the barrel, and possibly even from exiting a muzzle, air currents, etc. Maybe the route to roundball nirvana is throwing a better knuckle ball?

[W.R.Buchanan]

Maybe the route to roundball nirvana is throwing a better knuckle ball?

You got it! And really there is nothing more to it. You'd think that in 400-500 years if there was some magic secret, it would be very well known by now.

The only thing I think can have any significant effect on a round ball from a smoothbore is velocity. And it would seem logical that the faster it flies the truer it should fly, or maybe it's the other way around?

Now this is all assuming the round ball is actually round and not some bastard shape. Mine do have a sprue cut on them which I'm sure doesn't help, but since I am shooting at steel or paper targets at +/-50 yards it probably doesn't matter a whole lot.

I would love to see a group from Davey Crocket's Flintlock rifle, and see exactly how accurate that gun shooting a patched round ball was at 50-100 yards.. I doubt it was all that.

When our gun club reopens after the fires I have to sight in my M500 with my newly Vang Comped barrel. I will sight the gun in about 1" high at 50 yards and shoot a group which I will publish here. I will also try at 100 just to see what happens. I think being dead on at 75 yards is the optimal range to zero at.

The Vang Comp process is supposed to close down patterns on buckshot to below 10" at 25 yards, and I want to see that too.

Loads will be Federal Low Recoil Slugs and my Pumpkin Ball Loads, and Fed Low Recoil BS

Randy

[Maven]

For what it's worth, a number of NMLRA smoothbore champions use dimpled RB's, and if I remember correctly, a very tight patch. Also, to Mike's point about the drill press ball roughening/dimpling tool, I don't have a drill press so I tried using two coarse files: It took me less than 45 seconds on average to thoroughly dimple a .600" RB (haven't tested them yet though).

[jeremy360]

I think its airsoft guns that have a rough strip in the top of the barrel. It grips the rubber bb and then creates backspin on the bb. This gives it a little lift like the golf ball and makes it have a flatter pattern before it drops significantly. Less of an arc. they seem to get pretty darn impressive accuracy (for a plastic bb) by doing that.

Dont think that could be applied to a shotgun...but food for thought. Look up slow motion videos of airsofts guns like that firing.