Cast lead ball weight tolerance.

In casting 54 cal. .530 balls I am experiencing weights of 221.9 gr. to 223.1 gr. What would be acceptable + - tolerance for best accuracy?

Hi Piney
Pardon the pun but that is a loaded question.
For ultimate accuracy you need to have absolute repeatability.
Each ball needs to be exactly the same weight, volume, hardness, diameter and out of round with the sprue top dead centre and that is just the ball.
Remember one of the reasons a ball can be "light on" is a void in the casting meaning the center of gravity is somewhat different than the physical center of the ball.

May I suggest you cast a whole bunch then weigh them and see how they measure.
It has been my experience that you will find they weigh in groups and generally by moving the top and bottom groups tolerances overall can be tightened big time.
Then it is up to you to decide if it is 1.0 grain or 0.1 grain tolerance you want for target work. And how many Groups to put aside for target work.
By this I mean you may find that you have 20 at 225.0, 50 at 225.1 and 25 at 225.2. These could be put aside for target work but kept in seperate bags to be used seperately. This will give you 95 balls within 0.1 grains but in 3 seperate groups.

The rest will likely be plenty good enough for hunting and plinking.
Personally I look at 0.5% to 1% weight variance. I know I can't shoot anywhere near that well to notice a difference at this level.
Almost all of yours would fall under 1%.

Anyway I am sure those with more experience will provide a better response.

In the meantime keep on castin and blastin!

Throw the really light ones, back in the pot, then get out there and shoot the rest!

If you shoot offhand it doesn't really make much difference. Don't overthink it. Drop the ones with voids and wrinkles back in the lead pot, shoot the rest of them.

A mold should pour a consistent ball weight, but a 1gr. spread at 223gr. is OK. Weigh 100 balls and get the average. Throw out the balls that are more than 3-4gr. away from average. Personally, unless I see a void or really bad wrinkle, I don't weigh anything and shoot them all.
In reality, unless you use a balance scale, your powder weight spread is enough that your ball weight spread is OK. You can't hold the rifle still enough to see the difference in the 1gr. ball weight. Bench shooters get all OCD about consisitency, but there is more room for offhand shooters.

Make sure you pool a good puddle of lead on the sprue near the opening as you pour, It sucks lead down as it cools and if you don't have enough there, it can't suck the lead down, hence you get more weight variances.

I doubt the mountain men had scales and weighed their ammunition. I don't weigh mine either. I toss obviously bad ones back in the pot, the rest get shot.

Yup. Is the ball smooth, not frosty? Shoot it
Yes everything needs to be exact to get consistent results
So .05 or .01 grain is great
But you load via a volume measure. Do you throw within .01 or .05 or even one grain
Do you get exactly.25 grams of lubricant on each patch, ram with exactly 22.7 pounds of pressure. Do you cut your patches at the muzzle, you think your with in a 3/7000 of a pound on each patch? Do you think pre cut patches are with in a grain?
I bet there is three grains difference in my powder charge from shot to shot. So I get a two grain different ball and this patch might have a touch more lube then that patch
Bambi won’t care. Most trail walks types shoots won’t matter. Only shooting a x in a paper shoot will it matter. And off hand or a warm day or a cold day or a slight wind or high humidity is going to count more then a two or three grain difference.

Frosty balls are happy balls. They are full filled and best to shoot IMHO

Less than a 2 grain difference I doubt you will ever see a difference. how they shoot.

PineyCreek said:

In casting 54 cal. .530 balls I am experiencing weights of 221.9 gr. to 223.1 gr. What would be acceptable + - tolerance for best accuracy?

Click to expand...

Using a one or two cavity mold?

Here is an article that looks into this a little - Ball weight accuracy.