ball roundness

[Wncman]

Bear in mind that cast balls will have a flat spot for the sprue, and some may have a slight nub at the gate where the molten lead was poured into the ball mold. Can't get much more of an out of round than that. The sprue is compensated for by loading with the sprue up and centered. Weigh the balls to have the same weight ball used for each shot and to eliminate the cavity that sometimes is drawn into the ball as the molten lead cools. Some will roll the freshly cast balls between two plates to smooth out the sprue. Some just take care to always load with the sprue up and centered in the bore, relying on the concave loading jag to smooth the sprue. And of course, with soft lead there is the factor of obturation as the ball is slightly compressed on firing to conform to the barrel within the patch. Since these balls are being fired in a smooth bored barrel, I don't think that the slight out-of-roundness will have significant effect.

Simple .. tumble them in a suitable tumbler ...

I tumbled some in a moccasin sitting around the campfire at a southeast rendezvous years ago after a discussion with a few folks about the dimples in a golf ball and its flight . It did erase the spruce. (.62 Fussil ) perhaps it helped for the few shots I made after.

Simple .. tumble them in a suitable tumbler ...

 

[smoothshooter]

i have ordered 3 round ball moulds from a custom mould maker and every single one of them is 4-5 thousands out of round. How much will this affect accuracy in my smooth bore. im shooting for score with this gun so need the best.

Will not matter. In the loading process the ball is subjected to distortion from the ramrod end, and having rifling grooves and patch fabric weave patterns impressed into the sides of the ball.
It all evens out.
If it still makes you nervous, tumble the balls for a few minutes.
I don’t pay any attention to sprue orientation either as long as I am using a mold that leaves a significant sprue protrusion.

 

[smoothshooter]

i tried that last week while it didnt change much except make the balls slick

I have done that very thing myself. Works great.

 

[Greenjoytj]

i have ordered 3 round ball moulds from a custom mould maker and every single one of them is 4-5 thousands out of round. How much will this affect accuracy in my smooth bore. im shooting for score with this gun so need the best.

Considering how the mold cavities are formed cut with a rotating cherry or swagged to finished size. I believe if the OP is measuring a slight out of roundness the cause is the mold blocks are slightly misaligned.
Perhaps there is a known technique to correct slight misalignment of the mold blocks.
It might be as simple as a few taps with a non marring hammer.

 

[Oldbear63]

I made a ball swage with two steel 1 1/2" cylinders and a 1/2" ball end mill. I can swage the sprue out nicely with this, though I have not done a thorough test for accuracy. It does tend to flatten the balls a bit or even create a rim if I hammer too hard.

Something I realized: From a rifled barrel our balls travel in a spiral out to our targets. A more perfect ball should produce a tighter spiral. When we shoot we are aiming for the X, but the ball is travelling in a spiral and the LEAST likely place for the ball to hit is the X! This explains why our targets have groups instead of one ragged hole. With perfect bullets we should have perfect trajectories. If we had complete uniformity of powder, patch and ball we would have a tighter hole, but it might not be where we were aiming as unform shots would only intersect the target at the same place in the spiral trajectory, but not necessarily where we aimed.

 

[Dude]

Something I realized: From a rifled barrel our balls travel in a spiral out to our targets.

Huh?

How could it travel in a spiral??? It can only spin around its axis in a straight line from the bore. At least, that's the way it's supposed to happen.

What makes you think it travels in a spiral?

 

[45man]

Out of tound a tad will mean zero on the target, no mold made will cast round anything. As a mold heats the dimensions change in different directions since there are two halves, not a hole in a hunk of one piece metal. I make my own bullet molds and help the problem by heating the mold and turning the cherry in it by hand with a wrench. I get very close to round but still not perfect.
The hotter a mold gets, the more out of round it will be.

 

[45man]

Huh?

How could it travel in a spiral??? It can only spin around its axis in a straight line from the bore. At least, that's the way it's supposed to happen.

What makes you think it travels in a spiral?

Depends on twist rates. I shot IHMSA and you could see the spiral. ThE S&W .44 with 240 gr bullets would spiral around the flight path but changing to a 250 gr would eliminate it. The 1 in 18-3/4 twist was too fast for a 240 gr. The Ruger's 1 in 20 was perfect for a 240 gr.

 

[ZUG]

Shooting in NRA High-power rifle matches you can see the bullet's "smoke trail" and it "spiral" towards the target.

 

[Clark Badgett]

Shooting in NRA High-power rifle matches you can see the bullet's "smoke trail" and it "spiral" towards the target.

The bullet does not spiral, it spins about its axis. The vapor trail looks like a spiral because of the imperfections of the vapor.

 

[ZUG]

The bullet does not spiral, it spins about its axis. The vapor trail looks like a spiral because of the imperfections of the vapor.

You are correct - I used the wrong choice of the word "spiral" - mia culpa ---.

 

[Eric Krewson]

A guy stuck me with an out of round Lyman mold on a trade, it throws .535 on one side and .528 on the other. I was expecting really bad accuracy out of these balls but they shoot the same as the balls out of a mold that throws perfectly round balls.

 

[stikshooter]

i tried that last week while it didnt change much except make the balls slick

Try putting them in your horses saddle bag , now that's historical !/Ed

 

[Oldbear63]

Huh?

How could it travel in a spiral??? It can only spin around its axis in a straight line from the bore. At least, that's the way it's supposed to happen.

What makes you think it travels in a spiral?

I observed this one day when the sun was just right; I could see my balls traveling down range in a perfect spiral.

There is a YouTube video about the statistics of 5 shot groups (nearly useless, you need hundreds of rounds to get statistical signifigance). One point of the video is that the LEAST likely place for the bullet to land is at the exact point of aim. This is easily explained as the ball/bullet travelling in a spiral to target.