Ever cast a bad batch of Roundballs?

[Carbon 6]

I of course, am assuming the ball is actually round and the mold is in tolerance.

I have examined many balls from many molds and have yet to find one that is perfectly round, So I assume that no balls are actually round. The "tolerance" is simply the variance that we choose to be acceptable. What is the acceptable variance (tolerance) for weight?

 

[Carbon 6]

A void inside the ball means it will not spin without wobbling.

A foot ball player can throw a "perfect spiral" or a ball that wobbles (technically both wobble) and still hit his mark. But from observation the more the ball wobbles the shorter and slower the ball seems to travel.
Does wobble in fact affect accuracy or does it affect velocity?

Has anyone done a blind accuracy test of culled balls in incremental percentages?
At what percentage does the deviation become a noticeable factor on paper, and is that deviation within the accuracy of my scale ?

Do you touch your balls with your fingers when you weigh them? (this will add weight)

Do you have a cabinet or protective cover for your scale, as breath and air currents can change scale readings?

Sorry, kind of went off on a tangent there.

 

[Griz44Mag]

I have examined many balls from many molds and have yet to find one that is perfectly round, So I assume that no balls are actually round. The "tolerance" is simply the variance that we choose to be acceptable. What is the acceptable variance (tolerance) for weight?

I agree, there is no such thing as a perfectly round - round ball. That's why I use the term "tolerance" the same as you use it.
The right answer for your question is based upon the needs/wants of the individual.
For round ball shooting I seek 1-1/2" groups at 50 yards.
This gives me a 3-4" group at 100 yards which is my self imposed limit for hunting whitetails and hogs.
This also gets me a .75" group at 25 yards - works great for rabbits using small calibers, although I have been know to pop a bunny with my deer gun (.54)
I have round ball guns from .36 to .75 caliber and even the smooth bore Bess will do that if
I maintain a .5% tolerance in weight with my cast balls.
For the .350 ball that's .4gr under the anticipated 65gr weight.
For the .735 ball that's 3.7gr under the anticipated 598gr weight.
For me, that works, as long as I do my part at the trigger.
I have what I call a "perfect" ball in each caliber I cast in my standards box. (A pill box with compartments)
I simply place that on the scale and zero the scale.
From that point it is fast and easy to place ball after ball after ball on the scale and reject all balls that show a (-) weight in excess of the tolerance for that size ball. I can screen a hundred balls in about 10 minutes.
The ones that fail go back to the pot.

 

[Griz44Mag]

A foot ball player can throw a "perfect spiral" or a ball that wobbles (technically both wobble) and still hit his mark. But from observation the more the ball wobbles the shorter and slower the ball seems to travel.
Does wobble in fact affect accuracy or does it affect velocity?

Has anyone done a blind accuracy test of culled balls in incremental percentages?
At what percentage does the deviation become a noticeable factor on paper, and is that deviation within the accuracy of my scale ?

Do you touch your balls with your fingers when you weigh them? (this will add weight)

Do you have a cabinet or protective cover for your scale, as breath and air currents can change scale readings?

Sorry, kind of went off on a tangent there.

 

[Griz44Mag]

I think my mouse doubled up that click, sorry folks.
For Carbon 6
My opinion only - no facts to back it up -

I would think wobble would affect both velocity and accuracy since it causes disturbance in the air flow around it.

I do not know of any blind testing - only have my own experience and confirmation from Dutch that he got the same results.

The residues from your fingers would not be detectable with a powder scale unless you have been eating Cheetos.

Air currents from my AC or overhead ceiling fan will cause fluctuations in the readings of .05-.1 grain max. That's not enough to cause disruption in weighing lead balls. I do turn off the air flow when loading for precision rifle powder charges, but we won't talk about that here ()

 

[Dphar1950]

In the first place, the question refers to round balls.

From the O.P.
"However if weight doesn't matter, and there are no obvious deformities is it possible to have a bad batch of cast RBs?"



Sorry, have to disagree with that one.
One grain difference in a .350 ball (65gr) is a 1.7% massive defect. It's going to wobble - A LOT.
One grain difference in a .575 ball (231gr)is less than .4 % and in accuracy is undetectable.
One grain difference in a .735 ball (598gr) is less than .2%, one I would consider almost perfect.
Besides that, we don't talk about "unmentionables" here....

You can disagree if you like. But you were not there when I did the milling experiment and are guessing.
Yeah I know about the unmentionable thing but its where the data was. AND its not just air bubbles and such. There are reductions in density in the casting (is that better) besides. Those being light not only were likely to have a void they also had inconsistent variations in the reduced density area. On those with nominal weights this was well centered in the bullet and consistent in growing and disappearing (I believe this is the result of shrinkage as the casting cools) on those the were lighter its was not centered and would even get larger and smaller as I milled down through the castings. Interesting was that the bullets that were more than +1 grain were often uniformly solid. Me? I don't bother weighing round balls. Nor to I cast any unless they are a size I can't buy off the shelf like Speer RBs. Casting projectiles I make darned sure the melt has been heated long enough to be uniform. I flux the heck out of it as soon as its well melted and again before I start casting. Cast culls until the mould is hot, I warm it on the edge of the pot as the melt is heating. I use a dipper pot not a bottom pour which IMO is a huge waste of money and time. They simply will not produce consistent projectiles. I tried two of them years ago
The OP wanted to know about bad cast bullets. I answered with things I found out over 20 years ago. I would have to go back and find the article I wrote on this to know for sure. In slow twist barrels the flaws are less a factor. The only thing I cast balls for has a 80" twist and if they look perfect they shoot OK. If I were REALLY serious I would weight everything. OH! Forgot I have a rifle that I shoot .498-.500 diameters from and I cast these too. When I run out. But when I cast these I cast large batches because large batches produce more consistent projectiles.

 

[Carbon 6]

The residues from your fingers would not be detectable with a powder scale unless you have been eating Cheetos.

()

It does on my scale and for me.. I suppose some people may have dry enough fingers for it to not be a problem, but it is something to consider.

 

[Carbon 6]

If your ball has a sprue and is not loaded exactly center to the axis of flight, would not centrifugal force from rotation cause the sprue to create an increasing wobble and thus affect accuracy ?

 

[Walkingeagle]

If your ball has a sprue and is not loaded exactly center to the axis of flight, would not centrifugal force from rotation cause the sprue to create an increasing wobble and thus affect accuracy ?

Yes.
Laws if physics folks.
Walk

 

[Griz44Mag]

Let me do some math.....
In a 1:66 barrel at 1500FPS
1500 fps for 50 yards (150') - flight time is .1 sec.
With a 1:66 twist that's 5.5' per rev
Revs to target would be 27.27
RPM would be 163.64
SO - how wobbly would that be would depend on how far off center the sprue is and how much weight the sprue is?
I dunno, but it was fun getting this far.....

 

[Griz44Mag]

It does on my scale and for me.. I suppose some people may have dry enough fingers for it to not be a problem, but it is something to consider.

Let's see:
My scale is accurate to .01gr
On a 54 cal round ball - 231 gr, that's 0.0004329% - MAXIMUM. You must have some HEAVY finger oil... LOL

 

[Carbon 6]

Revs to target would be 27.27
RPM would be 163.64
SO - how wobbly would that be would depend on how far off center the sprue is and how much weight the sprue is?
I dunno, but it was fun getting this far.....

Exactly,
The weight of the sprue would increase with ball diameter usually.

 

[Carbon 6]

Let's see:
My scale is accurate to .01gr
On a 54 cal round ball - 231 gr, that's 0.0004329% - MAXIMUM. You must have some HEAVY finger oil... LOL

How about a .32 cal ?

 

[MrMackc]

Yes and in particular a wobbleing round ball will not have the same air drag resistance as a football with wobble. But why am I worrying about wobble in a round rifle ball anyway, HaHa!
...just practice, practice, and practice some more, and if you are getting worse with practice, then get a mentor to check you out and if you are still worse, with the mentor than before, shut down and you and the mentor should drink a stout Bourbon and branch water, It may not improve your shooting, but you will probably feel better.

 

[Griz44Mag]

How about a .32 cal ?

Now we are getting silly?

 

[Carbon 6]

Now we are getting silly?

Ok, never mind then. Thank you for your thoughts. I enjoyed them.

 

[Kansas Jake]

As far as symmetry, the ball will normally be upset a bit when starting it in the barrel unless you use a loose patch. I assume the upset is along the center axis of the ball. In other words the ball is lengthened a very small amount.

 

[Griz44Mag]

Ok, never mind then. Thank you for your thoughts. I enjoyed them.

LOL, as did I.

 

[45man]

Let me do some math.....
In a 1:66 barrel at 1500FPS
1500 fps for 50 yards (150') - flight time is .1 sec.
With a 1:66 twist that's 5.5' per rev
Revs to target would be 27.27
RPM would be 163.64
SO - how wobbly would that be would depend on how far off center the sprue is and how much weight the sprue is?
I dunno, but it was fun getting this far.....

The formula is MVX720 divided by twist to get 16364 RPM's.
I cast perfect balls and bullets and was able to hit steel chickens at 200 meters with my .54 Hawken. The sprue can be a little off with no affect. I use a ladle only and have explained to keep the ladle tight and hold it in place so as the ball shrinks, it will take molten lead from the ladle. Don't depend on the sprue to feed a mold.
Now my friend has 3 bottom pour pots he used all at once with a pile of molds one day at work. He filled boxes with balls and there was not a single one I would shoot. I went in his garage where he casts and there was enough lead splatters on the bench and floor to make 1000 balls. Then the pots would cycle so slow that lead got cool. I went to a Lee production 20# pot and will not look back.

 

[tenngun]

‘So Jeb, I seen ya was a lookin’ at one of the Hawkin rifle guns thar on Subletts blanket, hows come you didn’t put up beavers fer it?’
‘Wal I was, it’s a 32 bore, and that’ll drop buff er bugsboys fer sure. But I would need me a new mold what to run ball with. D~~m my eyes if’s all he had was a .526 mold, while I’m a thinking I would need a .530 fer it ta shoot right’