Author Topic: Smoothbore & dimpled RB  (Read 6367 times)

wet willy

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Smoothbore & dimpled RB
« on: January 18, 2015, 01:27:06 AM »
How to make a "dimpled" RB?

The Jan 2015 "Muzzle Blasts" has an excellent article by Jim Van Eldik on the use of a "dimpled" RB in a smoothbore and resulting in measurable accuracy improvements. He describes making dimples between a rasp and file ...after filing off the sprue. Looks like this is a time consuming, one-at-a-time process.

Anyone on the forum have a less labor-intensive method?

FrontierMuzzleloading

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Re: Smoothbore & dimpled RB
« Reply #1 on: January 18, 2015, 01:51:25 AM »
He basically Knurled the ball up to a larger diameter and it shot better. I highly doubt the dimples did anything to make the ball shoot better.

Offline Natureboy

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Re: Smoothbore & dimpled RB
« Reply #2 on: January 18, 2015, 04:30:56 AM »
  They put dimples on golf balls to help them fly straight.  I would think that dimples would only help round balls if they were shot out of a rifle, but would probably lower their speed.

Offline WadePatton

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Re: Smoothbore & dimpled RB
« Reply #3 on: January 18, 2015, 04:43:16 AM »
(from my early years/distant past)

Dimples on a golf ball operate to move air from directly in front of the ball, via spin the clubface imparts onto the sphere at impact/launch.  Without spin, the ball will knuckle/wobble as if dimples weren't present.

This spin is mostly backspin which, coupled with the angle of the clubface, provides lift.  Sidespin causes left and right movement of the ball in flight.  Unintentional side spin is called "hook" and "slice" -the hallmarks of the duffer.  INtentional sidespin is called "draw" and "fade" the hallmarks of the low-handicapper/professional.  Backspin counters sidespin and this is why it's easier to fade a 4-iron than a 9-iron.  This backspin-amplified by dimples is what helps the ball fly "straight".

I was _way_ into this when Maxfli/Dunlop came out with the DDH (dodecahedron) dimpled ball, which gave the ball perfect dimpular symmetry (and different sizes of dimples).   

I'm not up on non-spinning motional directivities of spherical objects, so I can't cross-tabulate to a smoothie.

See y'all at the 19th.
« Last Edit: January 18, 2015, 04:48:12 AM by WadePatton »
Hold to the Wind

Offline Elnathan

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Re: Smoothbore & dimpled RB
« Reply #4 on: January 18, 2015, 05:34:30 AM »
Nathan Kobuck wrote about trying the practice a couple years ago, and he also thought it help with accuracy:
http://buffalotrace1765.blogspot.com/2011/03/chewed-bullets-flying.html

If you scroll down to the comments, the last one has some period commentary to the effect that they were considered more lethal as well as more accurate.
A man can never have too much red wine, too many books, or too much ammunition -  Rudyard Kipling

Offline Scota4570

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Re: Smoothbore & dimpled RB
« Reply #5 on: January 18, 2015, 08:51:58 AM »
Why not tumble them with steel birdshot and graphite. 

Offline Hungry Horse

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Re: Smoothbore & dimpled RB
« Reply #6 on: January 18, 2015, 06:50:07 PM »
 You don't need steel shot, or black stuff, that gets everywhere but where it will help. I just throw a handful of .595 round balls in a big old baking powder can I got from the local school cafeteria, and throw it in the bed of my truck for a couple of days. They roll around and dimple themselves up pretty good.
 I found years ago smooth, shiny, bore size balls, that all weigh the same, aren't your friend in a smoothbore. I use greased old wool blanket discs for wadding, over the bare ball.

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Offline old george

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Re: Smoothbore & dimpled RB
« Reply #7 on: January 18, 2015, 08:13:34 PM »
I'm with Hungry Horse ;D Wade just left me dazed and confused. Of course my wife says that's a given state with me. ::)

George
I cannot go to Hades: Satan has a restraining order against me. :)

Offline T*O*F

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Re: Smoothbore & dimpled RB
« Reply #8 on: January 18, 2015, 08:33:08 PM »
Quote
He describes making dimples between a rasp and file ...after filing off the sprue
Dimples is a misnomer.  They are actually raised burrs.  We used this method almost 30 years ago.  It had nothing to do with the "golf ball effect" but rather resulted in an oversized ball.  The burrs held a hard lube and when short started some of the burrs collapsed resulting in a tight, bore sized ball on the sides.  It would result in increased accuracy over a bare ball, but not over a patched ball.

The whole purpose of rasping and lubing the balls was for use in timed or speed shooting events to eliminate steps while still maintaining accuracy.

These articles are like reading "How I squirrel hunt" stories in Field and Stream magazine.  When you've been around long enough, you will run across new articles almost every year about the person's secrets, because he is a neophyte who thinks he has discovered something new.  Just remember--Everything old is new again.
Dave Kanger

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Offline Maven

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Re: Smoothbore & dimpled RB
« Reply #9 on: January 18, 2015, 09:57:44 PM »
Paul W. Brasky

wet willy

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Re: Smoothbore & dimpled RB
« Reply #10 on: January 19, 2015, 02:21:30 AM »
Thanks for the informative responses.

I note the referenced "Muzzle Blasts" article uses: dimpled, pock-marked, and stippled. Looks like many have thought about and tested various methods of making a RB/smoothbore combination work. Spending a few hours filing/rasping RB's seems liked an exercise requiring more patience that I have, but perhaps that's the best way ... or not! Many new ideas to try, including coating the as-cast ball in lube.

Offline SCLoyalist

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Re: Smoothbore & dimpled RB
« Reply #11 on: January 19, 2015, 03:38:21 AM »
You might be able to speed up the process by putting several balls on a steel plate or an old skillet, and using another piece of old steel to roll the balls around.  It would probably help if the skillet/plates were a bit rough and rusty if you're trying to 'stipple' the balls' surface.   


hammer

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Re: Smoothbore & dimpled RB
« Reply #12 on: January 19, 2015, 10:23:30 AM »
In the early-mid 1800's the East India Company trialled the results of imperfectly/perfectly round balls in smoothbore and rifled arms.   As cast versus rolled.   They discovered there was no perceptable difference in smoothbore while rifled showed better accuracy when perfectly round.   The smoothbore would have been in standard military paper cartridges.  Rifled would likely have been in a lubricated cloth patch.
David Harding, the author of the 4 volume study of Small arms of the East India Company, and others, considered the golf ball experiences.  They concluded there should be no comparison due to the extreme difference in velocity.
Interesting, perhaps.  Does show as earlier noted that there is nothing new under the sun.

Offline Daryl

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Re: Smoothbore & dimpled RB
« Reply #13 on: January 19, 2015, 09:42:52 PM »
Quote
He describes making dimples between a rasp and file ...after filing off the sprue
Dimples is a misnomer.  They are actually raised burrs.  We used this method almost 30 years ago.  It had nothing to do with the "golf ball effect" but rather resulted in an oversized ball.  The burrs held a hard lube and when short started some of the burrs collapsed resulting in a tight, bore sized ball on the sides.  It would result in increased accuracy over a bare ball, but not over a patched ball.

The whole purpose of rasping and lubing the balls was for use in timed or speed shooting events to eliminate steps while still maintaining accuracy.

These articles are like reading "How I squirrel hunt" stories in Field and Stream magazine.  When you've been around long enough, you will run across new articles almost every year about the person's secrets, because he is a neophyte who thinks he has discovered something new.  Just remember--Everything old is new again.


This is virtually the process I use with bullets produced in this mould, for my 14 bore rifle.  Taylor and I bored the mould with rounded 11/16" drill bit (.687"), which left a cavity slightly undersize to the .690" bore. Rolling the 'slugs' on a soft cloth with a very coarse wood rasp, enlarged the bullets to a snug fit & also gave a surface that held lubricant.

 The lightest hollow- based bullet weighed about 620gr. in pure and on up to 1,200gr.   The recoil with all of them (never shot anything over 800gr.) was memorable, to say the least, more than I appreciated.  I soon found out that paper ctgs. with round balls shot more accurately and recoiled less as well as loading more quickly due to the powder already in the paper ctg.

I subsequently found out the longest slugs, as about 1,200gr., when cast with a hooked screw-eye in place, made good duck decoy anchors.

Daryl

"a gun without hammers is like a spaniel without ears" King George V

Offline Hungry Horse

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Re: Smoothbore & dimpled RB
« Reply #14 on: January 20, 2015, 08:58:53 PM »
 In the Muzzle blast article, the original source for the dimple method, most definitely did say dimples, not stipples, or any other form of knurling the ball, which was an innovation done by the writer. He also specifies the ball be undersized. So, some of you are reading a lot into this that flat ain't here.

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