Figuring boolits per pound

[MikeS]

Hi All.

I have an interesting question. I know that there are 7000 grains per pound, so if casting a 230gr (actual as cast weight) boolit, in theory I should be able to cast 30 boolits per pound of lead. My question is if the theory holds up under real world conditions, or if there are other losses (perhaps from dross, etc.) that would make that number wrong?

[cbrick]

Possibly, sure. Also, is your as cast weight exactly 230 grains, the mold may say 230 on it but is your alloy throwing them at 233, what if they are 228? Dross could account for some loss also.

Is it all that important if you get 30 bullets per pound or 29?

Rick

[Sonnypie]

MikeS,
I actually do use weight to estimate the number of boolits.
If a feller had one of those counting scales it would be nice. I don't.
So I use a calculator and the bathroom scale.
Then I come up with something like a XXX.336576 part of the total number.
Now you know, and I know there aren't any 1/3rd of a boolit in that sack. There is only whole ones.
So I often round down to the nearest 10 and call it good.
Recently I did a private sale of some bullets. The deal was for 500. I put something over 530 in the box. Making darn sure the recipient got his moneys worth. (And I didn't care to have 30+ odd bullets laying around.)

The only place a real count matters much is for boxing them up after loading.
My pistol rounds get sacked, if they are the same powder charge.
For working-up loads (rifle), I rack or box them and have each corner, and one in the middle, written on with a Sharpie as to the powder weight. All else is the same.
That way I know where to look if in dought about the charge.

I only cast 2 boolit sizes now. But use weight to guess the number in the sack.

[Doc Highwall]

The only other thing not mentioned is, even with the alloy the the mould was manfactured for say Lyman #2, does the mould cast heavy or light.

In the end I am more interested in that the mould casts good bullets and not that the weight is as advertised.

If a mould casts good bullets with my alloy I just devide the 7000 grains with the bullet weight and let it go at that.

[gray wolf]

If you weigh out 10 pounds of alloy and cast some bullets, the bullets are your true return.
The waste, dross and spillage are gone.
So after casting weigh your finished goods, if it's 9.5 pounds then you have to live with 1/2 pound waste, ( for what ever reason )
9.5 X 7000 divided by the weight of the bullet being cast.
I would say in our situation the math will not get you the exact number.
Close but not on the money. If you need the count to the last bullet--count them by hand.
I weigh 100 and record the weight, if 100 slugs weigh 3 pounds then every 3 pounds is 100 bullets. If the bullets are for someone else I through in 10 or 15 extra and call it good.

[Sonnypie]

Ya made me curious, Doc.
So I weighed one sitting here.
221.2 grn
Supposed to be a 230grn.

So I guess I should be happy. I'm casting Scotch boolits.
Every 127.7777777778 I get a free one. :groner:

:lol::lol::lol:

[btroj]

You will always get 7000 grains per pound. This is written in stone.
The actual weight of the bullets produced will vary with alloy and the cavity size actually cut. Temp can make a difference too.
Another variable is the difference between the pound of lead you put in the pot and how much flows out the bottom. Dross, loss in skimming, spillage all cause some loss of alloy. Ideally these are small losses.
I figure I get at least 98 percent of my lead into bullets. Probably much, much more than that.

[williamwaco]

I can give you a SWAG based on 55 years of casting 158 grain .357 SWCs of various styles.

The math says that if I remelt all my culls and all the sprues I should get 44.3 bullets per pound. In my experience the actual achievable number is 40 to 41. I never count on more than 40 per pound.

What happens to the rest? I expect that most of it goes in the slag bucket.

That would argue for 9% waste which seems to high. I expect most of it is in weighing errors. I weigh bullets to the grain but I weigh 20 pounds of ingots on the bathroom scale.

This is unbelievable, just did a quick estimate, 200 per week for 55 years = 200*52*55 = 572,000.

[MikeS]

... Is it all that important if you get 30 bullets per pound or 29?

Rick

No, it's not important. I was just trying to see if the numbers work in the 'real' world. In other words, say I know the boolit weighs 228gr, and with the math that should mean that I'll make 30 boolits per pound, and say I want to cast up 1000 of these boolits, according to the math I will need 32.5 lbs of alloy to make them. How close to the actual amount of lead needed is that 32.5lb figure? Will I really need to have 35lb, or 42lb? I wouldn't want to start casting them when say I only have 33lb of that alloy on hand, and then find that I'm short by say 40 or 50 boolits, then have to make up another batch of alloy to finish the session. Or if in that situation I'd be better off mixing up another batch before starting the casting session, so I can make sure all the boolits are cast from the same batch of alloy. I hope I'm explaining what I'm trying to say correctly, I'm not sure that I am. Sometimes what I'm thinking, and trying to say don't always translate well to written words (one reason I'll never author a book!).

[btroj]

Aways figure on a little bit of loss. Sprue that falls on the floor, bits of sprue that fall off as dust or small bits. Dross. How much lead is left in the pot that can't be ladled out or flow thru the bottom pour?
If I was looking to cast 1000 bullets I would want enough alloy on hand for 1200 bullets.
I suppose the other question I have this- is it that critical to have exactly 1000 bullets? I cast however many bullets as I can and call it good. Might be 482 but could be 574 . Does it matter?

[williamwaco]

... say I want to cast up 1000 of these boolits, according to the math I will need 32.5 lbs of alloy to make them. How close to the actual amount of lead needed is that 32.5lb figure? Will I really need to have 35lb, or 42lb? I wouldn't want to start casting them when say I only have 33lb of that alloy on hand, and then find that I'm short by say 40 or 50 boolits. ...




I rarely have an exact number in mind when I start casting but on the occasions that I do have, I always cast around 10-15% more than I need because I know that:

I will find culls when I weigh them
I will find culls when I size them
I will create new culls when I size them.
I will drop some on the concrete floor.
I will create more culls during the seating process.
etc.

If the math said I needed 32.5 pounds, I would start with at least 37 or 38. 32.5 * 1.10 * 1.05. ( 10% extras, 5% waste )
And that assumes you can weigh 38 pounds accurately. I can't. +/- 1 lb = 30 bullets.

[BossHoss]

My equation for figuring out how many boolits i have in the can is this:


11.5 lbs of boolits

11.5 x 16oz = 184oz

184oz x 436gns = 80224gns

80244 / 250gns boolits = 320.8 boolits in my 11.5lbs give or take.

That's what i cast tonite with my 4 banger Lyman 429421

My mold throws at 250-1 gns.

Always seemed to be on the money give or take a couple.

[snuffy]

I seldom cast below half way on my pro 20 lee pot. So, you have to allow for that in your total lead required to cast your 1000 boolits. Then there's the sprues, do you keep accumulating them or toss them in when adding ingots?

Theory is nice to use when calculating how many boolits can come from a pound of metal. Even if it worked out to EXACTLY 230 grains per boolit, you cannot cast those last few boolits from the tiny amount of lead in the bottom of the pot.

If I'm aiming at having 100 boolits ready to load, then I usually cast 200. Culls account for at least 50% for rifle boolits, less for most handgun boolits.

[ku4hx]

I take the average weight of ten boolits picked at random then divide that weight into the weight in grains of the whole lot of cast boolits.

All I want is a ballpark estimate and in several decades of casting, this method has served me well.

Per my old bathroom scales I cast 31 pounds of 9mm boolits with an average as-cast weight of approximately 122 grains. (31*7000)/122=1,778.69. I call that 1,800 boolits and move on.