Weighing round balls

[Eljay]

I'm definitely finding that as I progress I cast fewer stinkers, and I spot more of them sooner in the process (and I do know what you mean about watching the dimple). Perhaps some day I'll get to the point where my reject rate from weighing is so low that it won't seem worthwhile. Perhaps I'll only do it during load development so I don't get some irritating flyer. Perhaps I'll be in the habit and do it all the time.

I just don't see it as being a big deal to weigh them. A little digital pocket scale that reads in grains is like $10. "American Weigh Signature Series Black AWS-100 Digital Pocket Scale" on Amazon - $9.56, free shipping if you're a prime member or order $25 of stuff.

There's some point in the workflow where I give the balls one last check before putting them in their bag. Usually it's dead time when I'm waiting for other stuff to cool so I can put it away. And instead of glance at it, drop it in the bag, it's glance at it, set it on the scale, pick it up, drop it in the bag or in the pot. The readout is instant and I just have some mental cutoff that it's either above or below and I act accordingly.

 

[George]

The concern isn't that the ballistics will change from the weight. The concern is that there can be voids in the lead, off center, which will make the balls do odd things. Weighing them and tossing the light ones is an easy way to detect this.

Yes, but most of us who weigh them don't go about that just right. If voids is what we are trying to avoid, then only the heaviest balls should be used. Save only those within your tolerance, .5 gr., for example, of the heaviest ball, and throw the rest out. I think most tend to group them within their tolerance, wind up with 2-3 ranges and call it good because they are shooting consistent balls within that group, even though some groups are very light, have big voids.

I'm not real sure we have correctly figured out the effect of voids on accuracy, either. I've never seen any sound tests of the theory, not sure how you would go about it.

Spence

 

[FishDFly]

Lately lots of folks have been quoting Mr. Dutch and his system recently.

He says weigh your balls especially if they are "swaged", that is where the big difference is, not as much in your own casting.

Some folks are perfectionists with their shooting and some are happy being mediocre in their shooting skills, each to their own.

Mr. Dutch brings a lot of insight into accurate shooting.

 

[roundball]

Plus there's the nagging question of just how far and modern do we want this grand old form of shooting to become that the settlers routinely did without digital scales, micrometers, etc....heck they often used a bag mold over a campfire to make a few balls on a hunting trip, or the fireplace in the cabin.
:hmm:

 

[dledinger]

Yes, but most of us who weigh them don't go about that just right. If voids is what we are trying to avoid, then only the heaviest balls should be used. Save only those within your tolerance, .5 gr., for example, of the heaviest ball, and throw the rest out. I think most tend to group them within their tolerance, wind up with 2-3 ranges and call it good because they are shooting consistent balls within that group, even though some groups are very light, have big voids.

I made mine into groups, like you said, but with a different thought process all together. My thought is that the group of heaviest balls is the highest quality....and then on down the line by groups. I'll use the lightest for the kids, the mid range for plinking and fun shooting, and the heaviest for load development and hunting.

I'm shocked at the responses from those casting their own and the indication of the tight tolerances they get. Aside from the savings, this improved consistency is a great case for me to buy some new equipment!

 

[dledinger]

Plus there's the nagging question of just how far and modern do we want this grand old form of shooting to become that the settlers routinely did without digital scales, micrometers, etc....heck they often used a bag mold over a campfire to make a few balls on a hunting trip, or the fireplace in the cabin.
:hmm:

Oh heck...I bought my last gun over 3G using my iPhone!

 

[roundball]

Plus there's the nagging question of just how far and modern do we want this grand old form of shooting to become that the settlers routinely did without digital scales, micrometers, etc....heck they often used a bag mold over a campfire to make a few balls on a hunting trip, or the fireplace in the cabin.
:hmm:

Oh heck...I bought my last gun over 3G using my iPhone!

And we both probably drive modern vehicles to the range and/or hunting instead of walking / riding horseback...but that really has nothing to do with the point I was sharing with George
:wink:

 

[Zonie]

IMO, if the ball is shot from a rifle, the most it will be displaced from the point of aim because of a internal void is 1/4 inch.

As for 5-15 grains difference in weight of the ball its effect on the trajectory path will show almost no measurable effect during flight.
That is, the rise and fall of the ball due to its different weight will be very small.

The shot could easily hit in a different place on the target though.

Why?

Because the weight (mass) of the ball has a lot of effect on the pressures produced by a given powder load.
The different pressure is directly related to a different velocity for the shot.

The mass of the ball will also have a lot of effect on how easily the ball accelerates while in the barrel.

These things combined can easily change the velocity of the shot and the different velocity's effect can have a measurable effect on the target.

For general hunting where the only requirement is to keep the shot in the "kill zone", the effect of a few grains difference in ball weight can be ignored.

For target shooting contests where the winner is decided by fractions of an inch variations in the ball weight can be very important.

 

[roundball]

.54cal balls:
One weighs 216grns.
One weighs 226grns.

What will be the difference in muzzle velocity?

What will be the difference in POI at 50yds? 100yds?

 

[dledinger]

I was just indicating that for me to own and shoot these guns involves a whoole lot of technology that wasn't available when sidelock or flintlocks were conceived or in common use. Though I purport to be "historical", I'm not fooling myself. Weighing some roundballs to stuff down my CNC machined, modern steel barrel doesn't seem over the top.

I though my comment was related to yours

 

[dledinger]

Zonie, Thanks for the input. I'm still not very happy with these variances, even if they don't have a significant negative impact. Can't wait to do some casting of my own.

 

[jdkerstetter]

...the most it will be displaced from the point of aim because of a internal void is 1/4 inch.

1/4" at what range? 25, 50, 100 yards? Distance makes a difference. 1/4" M.O.A. I understand. :wink:

Anyway, I was going to stay out of the fray here, but the way I see it, with the balls in question the standard deviation is less than 2.5%....to me that seems pretty good in our game. I bet most will never see the difference in their shooting.

Has anybody measured the difference in weight of thrown powder charges to see what the standard deviation is from one to the other in a 100 throws?

How about the difference in pressure during seating the ball? Wind, heat, humidity, difference in powder from batch to batch, etc?

Granted, you want to take as many variables out of the equation as possible if X's are the goal.

Maybe ball weight is one of the factors we can control, so we should be taking advantage of it. :idunno:

Me? With all the variables to cosider, I'd be happy with 2.5% deviation. Enjoy, J.D.

 

[Zonie]

I didn't say 1/4 inch M.O.A.

The ball rotates about its center of gravity. That's a law of physics.

The most off center the center of gravity could possibly be is equal to the radius of the ball and that is totally impossible because there is no material beyond the radius.

Now, knowing there are some folks shooting .70+ caliber guns I feel safe in saying the center of gravity couldn't be more than 1/4 inch off of the center of the ball so it will poke a hole who's center is 1/4 inch or less from the point of aim.

 

[Zonie]

Of course, your kidding aren't you roundball?

I didn't give any values because as you should know, no one has the ability to predict or calculate exactly what those would be.

Although I did not give any values (and won't here) I stand by my statement. The weight of the ball (among other things) has a direct relationship on the way the powder burns and the pressures (and velocity) it creates.

 

[jdkerstetter]

I didn't say 1/4 inch M.O.A.

I know you didn't. Had you I would have understood the 1/4" deflection would have been at 100 yards.

Not trying to be agrumentative, but you can't just say a 1/4" inch and be accurate. A 1/4" off point of aim at 25 yards is 1" off point of aim at 100 yards.

Same can be said for a 2" group at 25 yards will, in theory, equal an 8" group at 100.

That's why it's key to know the distance one is shooting at. Enjoy, J.D.

 

[roundball]

Actually I wasn't kidding.
The thread had a couple of interesting themes...specificity vs. the old ways.
Then you made some very strong matter of fact comments.

From past posts of yours my impression is you have ballistics calculator software or something, and I thought it would be a simple matter to crank in the different projectile weights and spit out a couple results...no?

 

[necchi]

Here' ya go Bill, have fun. http://www.ctmuzzleloaders.com/ctml_experiments/rbballistics/rbballistics.html

 

[George]

.54cal balls:
One weighs 216grns.
One weighs 226grns.

What will be the difference in muzzle velocity?

What will be the difference in POI at 50yds? 100yds?

Roundball, velocities can not be calculated, must always be measured. Once you have that, then you can play with trajectories, POI, etc. I posted an example earlier in this thread using 229.9 and 219.9 weight .535" balls. The velocity of 1758 was measured for the 229.9 ball, I then assumed the same velocity for the 219.9 ball just to show a ballpark comparison of the two trajectories. There was only a minimal change, none at 50 yards, 0.2" lower for the lighter ball at 100.

Spence

 

[roundball]

Roundball, velocities can not be calculated, must always be measured. Once you have that, then you can play with trajectories, POI, etc. I posted an example earlier in this thread using 229.9 and 219.9 weight .535" balls. The velocity of 1758 was measured for the 229.9 ball, I then assumed the same velocity for the 219.9 ball just to show a ballpark comparison of the two trajectories. There was only a minimal change, none at 50 yards, 0.2" lower for the lighter ball at 100.
Spence

That makes the same point for me...and I suspect most others are far better shooters than I am.
I'd never routinely be able to shoot hundred yard groups so small that a slightly lighter ball would suddenly open up the group size 2/10ths of an inch and I'd notice it.
And truth be known, in your example I assume each ball weight is actually only 5grns off on either side of the nominal ball weight. I couldn't look though a spotting scope and declare, uh-oh, that ball must have been a few grains lighter because its 2/10th of an inch off.
I'm not good enough at 100yds to notice a ball's POI shift by being a few grains lighter but my hats off to all those who are.
:hatsoff:

 

[biliff]

Reposting my inputs from another thread on pretty much the same topic.



05/18/13 03:26 PM - Post#1281655

Did a 50 yd. test with my .58 flintlock. 10 shots with selected ball that weighed 270 gr +/- 1 grain vs the rejects.

1 1/2" group with the good stuff. 2 1/2" group with the rejects.

Enough of a difference to use selected ball for stuff that counts. Rejects were good enough for practice vice remelting.