The Curse Of The Sprue

[Gun Tramp]

A perfectly round ball leaving the barrel would not be very accurate comparatively.

Hope this isn't too far off-topic, but is the roundball shorter than it's diameter when it exits the muzzle?

 

[firestick]

Read an article years ago about testing bullets of all types using damaged tips. What they did to those bullets was typical of half the hunting ammo used in the field. Damaged tips had little to know effect on accuracy. Even SLIGHT damage to the base proved to make them almost worthless. If the "push" is not true and even then becomes accuracy is a lost cause. I really doubt sprues when eyeballed to center forward will have near zero effect. Besides I bounce my rod lightly a couple times to make sure prb is seated tight. I always thought this took care of any sprue issue and that the pressure (psi) against the ball upon firing would cause deformation by flattening the soft material and forcing it further into the lands and groves of the rifling. Anyways I have always had better luck in the accuracy department doing it this way. If a sprue were to effect accuracy I suspect it would have to be about 3" long! LOL.

 

[Carbon 6]

Hope this isn't too far off-topic, but is the roundball shorter than it's diameter when it exits the muzzle?

Mine sure are.

 

[hanshi]

No sprue is why I really like the Lee molds. My other molds DO leave a sprue. Those I tumble a bit and the sprue goes away. Those with a sprue that I haven't tumbled are simply loaded sprue up and centered.

 

[Rifleman1776]

Boy! You must be old.

Yep. I am. Had others who also helped me. I lived near Friendship. Had Webb Terry, Vaughn Goodwin, Chuck Blender and many others who were NMLRA champions but whose names I have forgotten.

 

[Rifleman1776]

Mine sure are.

Good question. I have always felt we don't shoot round balls. We might load round balls but what comes out the muzzle definitely has to be sumptin else.

 

[Spikebuck]

The swaged balls I have used have been Hornady and they need better quality control. I've gone though boxes and found many to be out of round already and also some weight issues. Unless I sort through them, they can cause accuracy problems. I just throw the problem ones in a bucket to melt down when I cast my own. I use Lyman molds, which do leave a sprue, and I just load it pointed up and they shoot great...actually better than the Hornady swaged balls, on average. If a person is overly concerned with a sprue, use a Lee mold which basically leaves next to nothing. I've done the coffee can thing to reduce/remove sprues and have pretty much found it to be waste of time...meaning the sprue is "removed" but they don't shoot any better.

 

[mooman76]

Some have rolled them between two solid flat surfaces like sheets of glass.

 

[DOUBLEDEUCE 1]

In a nod to William Shakespear, maybe this thread could be renamed to “Taming the Sprue”...

 

[Oldbear63]

I have often watched my shots spiral down range to the target. If every ball has a slight off center balance point then every ball should spiral down range with a spiral diameter determined by the amount of the off centered mass of the sprue. Theoretically even a swagged ball should have some imbalance and some spiral.
If you are meticulously careful with powder measures and sprue placement then every ball should make the same number of spirals and end up at the same point at the target (though not necessarily at point of aim). A slight change in the powder or some other variable (lubricant, patch thickness, sprue placement) would affect the number of turns or location of the spiral as it intersects the target.
We are trying to hit a target with a corkscrew shaped ball trajectory that is affected by every variable that we put into our load.

 

[Britsmoothy]

I’ve also read of people placing them in a can and tossing them in the bed of the truck for a bit. The rattling and rolling does the same thing they’ve said.

If you did that on UK roads they would come out a spherical polyhedron.
Yes yes, I had to look it up

 

[Britsmoothy]

Hope this isn't too far off-topic, but is the roundball shorter than it's diameter when it exits the muzzle?

I have retrieved balls that are definitely shorter after firing.

 

[Josephg]

I always and have always loaded a round ball with the sprue down. One time my old shooting pard told me I wasn't supposed to do it that way. He said the ball can turn when pushing it down the barrel and get stuck. I figure if I can't see the sprue it won't bother me.

 

[Professor flintlock]

I dont notice enough of an accuracy issue to give it any real thought. If I was a competition shooter, maybe Id fret over it, but since Im not I dont worry about the sprue.

Ahmen sidney. A bench shooter might worry about it. But a hunter or an off hand shooter won't have a problem, unless you let the sprue engage the rifling. Just get the sprue as close to top dead center as you can. Small calibers .32 ect. need just a tad more attention.

 

[Professor flintlock]

Used to shoot off hand gun ,40 shot a ,405 ball and .020 teflon ticking rest assured that ball came out looking like a pill. I think that's what you need for accrucy. Would shoot one holers all day long. Used a tapered false muzzle to get it down the barrel. A Wiemer hand cut barrel. Too heavy for me now anybody interested in it. Rod England Vincent heavy barrel fancy build.

 

[robinghewitt]

Zeke Baker fixed the sprue problem with his improved ball mould, featured in his book, E Baker Remarks on Rifle Guns.
In a wild moment of impetuosity I bought a copy. I love that history connection you get from old stuff

 

[Rob Dinwiddie]

I tend to use the old Dixie molds that leave a huge sprue. I clip each one near the ball with a set of electricians pliars, then touch each one on the sprue on my belt sander and then roll them between two steel plates for ten minutes or so. It leaves almost no trace at all of a sprue.

 

[RAEDWALD]

The issue with sprue is not the aerodynamic blemish, but that the cast will, inevitably, have a small void near the top from differential cooling of the cast. This gives an inbuilt error of balance of the ball mass centre from the geometric centre. Hence the British Ordnance invested a very large (for the period) sum to change musket ball manufacture from cast to machine swedged following trials making Brunswick Rifle belted balls. The machine swedged musket balls came out on average 4% heavier through having no void.

Logically, if one uses cast balls, the sprue should be directly down so that the anterior has slightly more mass than the posterior giving a very slight mass stability. Now whether the difference is measurable even in competition is questionable, but it can do no harm. The trick is in finding a way to load the ball with the sprue directly down the barrel but a diligent t'internet search will turn up some methods.

 

[cositrike]

I was going over some old Muzzleloader mag's and in May/June 1998 issue there is a article by Darwin Johnston tilted "The Curse Of The Sprue." In it Darwin talks about the fact that the sprue on lead balls is a "Significant blemish on the surface of the ball that can seriously affect the location of the center of gravity, hence its balance, and consequently its accuracy." Darwin goes on and talks about why the sprue causes the lead ball to become unbalanced. As the ball rotates in the riffling and exits the barrel, this spiral action on the ball speeds down range with a unbalanced center of gravity (c.g.) will depart on a path tangent to the spiral. This tangential, a lateral departure from the center of the bore, influences the accuracy of the shot. Daren gives an example, "Using a rifle having a 48-inch twist and seated cast ball with its c.g. located at a distance from the center of the bore equal to the thickness of a piece of paper, 0.004 inches, the ball can be expected to strike no closer than 1.88 inches to an target 100 yards away." Stated more dramatically, Darwin states that this unbalanced ball will strike on the circumference of a 3.76-inch diameter circle centered on an aiming point 100 yards away. Also, patching, starting and ramming inconsistencies can affect the c.g. by as much as 0.015 inches from the center of the bore. Darwin goes into much math with "tables of predicted errors" and gives two conclusions. First, is having a rifle with a slow twist rate and states that "Perhaps this is why we often refer to rifles having a slower twist rate as ball guns," Second, given a choice, use cold swaged balls, or carefully trim the sprue from smooth, round cast balls before using them. After reading this article, my question is, what would you use to remove the sprue, a file, knife, etc?

I don’t bother with the sprue. I load sprue up and have never found a problem. Just me and my opinion.

 

[dragnetbill]

I was going over some old Muzzleloader mag's and in May/June 1998 issue there is a article by Darwin Johnston tilted "The Curse Of The Sprue." In it Darwin talks about the fact that the sprue on lead balls is a "Significant blemish on the surface of the ball that can seriously affect the location of the center of gravity, hence its balance, and consequently its accuracy." Darwin goes on and talks about why the sprue causes the lead ball to become unbalanced. As the ball rotates in the riffling and exits the barrel, this spiral action on the ball speeds down range with a unbalanced center of gravity (c.g.) will depart on a path tangent to the spiral. This tangential, a lateral departure from the center of the bore, influences the accuracy of the shot. Daren gives an example, "Using a rifle having a 48-inch twist and seated cast ball with its c.g. located at a distance from the center of the bore equal to the thickness of a piece of paper, 0.004 inches, the ball can be expected to strike no closer than 1.88 inches to an target 100 yards away." Stated more dramatically, Darwin states that this unbalanced ball will strike on the circumference of a 3.76-inch diameter circle centered on an aiming point 100 yards away. Also, patching, starting and ramming inconsistencies can affect the c.g. by as much as 0.015 inches from the center of the bore. Darwin goes into much math with "tables of predicted errors" and gives two conclusions. First, is having a rifle with a slow twist rate and states that "Perhaps this is why we often refer to rifles having a slower twist rate as ball guns," Second, given a choice, use cold swaged balls, or carefully trim the sprue from smooth, round cast balls before using them. After reading this article, my question is, what would you use to remove the sprue, a file, knife, etc?

An interesting topic; it reminds me of a past experience dealing with round projectiles and their failure to hit the intended target. Please forgive the reference, but, the projectile in question was a golf ball. A friend who hosted an annual golf gathering/tournament announced one year at the opening ceremony that he had decided to alter the rules to allow the switching of the ball in play on the green so as to allow the use of one manufactures new ball that was guaranteed to be "TRUE" to round; he obviously thought that this was going to improve his putting performance.
After the ceremony I greeted him warmly and gently burst his bubble; I said to him, "You know friend, I've watched you putt for years now; did you ever consider that these new "True" balls might actually cause you to miss more putts; after all they will in theory have no chance of varying from where you putt them to fall in the hole."