Can temperature alone explain this?

[Flintlock Hokie]

My first batch of .490 round balls cast from wheel weights averages 173.6 grains and they are shiny. My second batch, cast from a much larger supply of wheel weights, averages 171.1 grains and they are frosty. The standard deviation for the second batch (based on 35 samples) is an amazing (to me anyway) 0.21 grains!

The first batch was cast at an unknown temperature because I had not yet purchased a thermometer. The second batch was cast at 650 to 670 F.

I understand that frosty versus shiny makes no difference in bullet performance. But can the difference in surface finish and weight be explained only by temperature differences when casting? Or is it more likely that there is an alloy difference between batch one and batch two?

Thanks!

[jdgabbard]

In my experience, surface finish is a matter of alloy and temperature when casting. Weight is a combination of alloy and methodology/consistency. An alloy of PB when cast hot, may very well show no signs of being frosty, but the more antimony in the alloy the frostier they become. Likewise, an alloy cast cool, so to speak, typically shows little to no signs of frostiness. However, cast at proper temp, will yield frosty boolits. Weight on the other hand, has to do with alloy and consistency. A consistent poor helps to prevent voids, which can cause variances in weight (casting frosty in my experience can help to prevent these as well). However, variance in weight alone is typically a matter of consistency itself. Inconsistent heat, pour, speed, and technique all play into weight variances. I hope this answers your question.

[telebasher]

I'm just curious I guess, but round balls are generally made from pure or dead soft lead so they can obturate at the low breach pressures produced by black powder or one of it's facsimiles. Have you shot wheelweight round balls from your rifle and what kind of accuracy did they produce? If I can scratch the lead with my thumbnail it is soft enough for my guns but maybe YMMV.

[Flintlock Hokie]

Having to shoot pure lead is an old wives's tale! Apparently some of the old-time writers talked about the benefits of using hardened lead. I shot the target below with my flintlock with open sights using wheel weight balls. Distance was 50 yards. There are 10 shots in the target though only nine are clearly visible. After my first shot I adjusted my sight picture. My 65 year old eyes are happy with the results.



Note: I've never been accused of being a true marksman.

[runfiverun]

to the O.P.
it's the antimony..

[Flintlock Hokie]

Sb affects weight or surface finish or both?

[45-70 Chevroner]

Great shooting there. My understanding of the use of pure lead or dead soft was that the ball is ingraved by the patch to impart the spin to the ball. In the use of WW balls I had to use a thinner patch to be able to seat the ball and patch down the barrel. Usually the soft lead shot better than the WW. I have shot a lot of WW balls but mostly for plinking out to 50 yards. For really good groups at a 100 yards I had to use soft lead, most of my groups at that distance were in the 2" to 3" range. The shooting was done with a 50 caliber cap lock, Custom made Charley Maggard Rifle. The rifle is capable of better than that.

[runfiverun]

both, pure lead don't frost.
antimony causes a surface hazing look, [frosting] it actually looks like a bunch of pine tree branches laid on top of each other on the surface of a boolit.
it's why tin is so often recommended when casting with it, the tin allows the alloy to break through that surface and gives the mold fill out it's noted for.
it's also lighter than lead [airc about 40% lighter] so even a smallish [5-6%] change out of the two makes the weight noticeable.

[telebasher]

Really good group/shooting for any age eyes. Makes me wonder what it would do with soft lead, might be interesting to compare alloys and see what the rifle says. Either way still a good group!

[leadman]

I shot my first elk with a COWW ball out of my 58 Cal. H&R Shikari. Hornady did and may still sell harder lead balls.
That is very good consistency of weight.

[Flintlock Hokie]

I dropped from .495 to .490 balls and from .018" to.015" patch when I switched to WWs. I switched because I was concerned pure lead wasn't hard enough to get sufficient penetration on an elk. The wheel weight balls did the trick. I took a bull elk at 42 yards with my flintlock. The ball passed diagonally through his chest cavity and lodged on the far side just under the skin.

[Toymaker]

Pure lead for roundball is best for obturation, sealing, engraving the rifling, etc. There is also less wear on the rifling. BUT there is no reason slightly hardened lead, such as WW, can't be used. In fact, with a new barrel I'll shoot a few hundred hardened RB to smooth the rough spots and sharp edges on the rifling. Obviously in 1840 and before they didn't have WW and lead was the easiest metal to use for the purpose. The use of pure lead only came back in the early days of the resurgence of muzzleloading due, mainly, to the poor quality of barrels and rifling used in replica's. Barrels today are greatly improved, but use of hardened lead exclusively will shorten barrel life. Groups will suddenly go to pot requiring a thicker patch or larger ball.
As to ball weight, your results are excellent. As the lead solidifies in the mold a true void will form inside the ball. The size of the void will depend on the temperature of the lead, the mold, how fast it cools and solidifies as well as some climate factors. Take a few of the lighter balls and roll them on a table with a knife edge so they're cut open. You'll see the void. Several years ago the NMLRA magazine MuzzleBlasts had an excellent article on this. I weigh my RB in 0.5 grain groups. The heaviest get used in competition and the lightest get re-melted.
Want to have some fun?? Mic the diameter of your RB. Compute the volume of your RB (volume of a sphere), convert to metric if necessary and multiply by the density of lead. That's what your RB should weigh.

[leftiye]

To answer your question - yes, it could all be temperature. I'd almost bet your technique, etc. didn't change from the first batch to the second. Frosting being influenced by alloy etc. aside (because it occurs anyway with almost all alloys), most alloys will cast best just at frosting's cooler edge, just as you did. Fillout will be better, weight will be up, and more consistent. The key is that the alloy doesn't freeze before fillout is accomplished, and for a second after filing the alloy is molten.

[h8dirt]

Stick with soft lead. It's not an old wives tale.

[dondiego]

Many matches have been won with cast round balls in wheel weights. Seen it.

[Flintlock Hokie]

... but use of hardened lead exclusively will shorten barrel life.

Wouldn't that also apply to shooting boolits cast from WW LEAD. Why would barrels made for shooting boolits behave differently from those built to shoot round balls?

[runfiverun]

I'm taking a stab at it here.
softer steel for the lower pressure..

I can tell you antimony on the surface of a boolit has little dendrite hooks and they will wear away at the surface of steel.
I dunno about how much less life a barrel will have doing this but I'd guess a modern revolvers barrel life could be shortened from 100-k rounds to 90-k by it.
unless a wash was present then you'd have a continuous pick-up and lay down pattern going on.

[243winxb]

likely an alloy difference

[Flintlock Hokie]

With proper patching, a round ball never touches the metal of the barrel!

[olafhardt]

You have very little chance of have two melts of wheel weights of the same composition. The composition very likely changes as you cast from it. This doesn't seem to make a whole of difference usually but I have noticed casting charactestics changeing as I used up the pot.