Cooling Minies

[Ken Hansgen, 11094]

Here's another thought. While casting .58 cal, Minies this morning, I got to thinking. The lead in them must cool and solidfy from the outside in, and they are big and fat, so do they still have a liquid core when I drop them from the mould? And when I drop them they almost invariably lie on they sides, as they are pretty pointed, and they fall from the mould point first. So wouldn't any voids form on the upper side of the still-cooling core, and wouldn't that cause them to be unbalanced? Should they be allowed to cool vertically instead of horizontally? I do weigh them and shoot the heaviest at targets. Does that lessen the effect? Has anybody else thought of this?

[Greg Ogdan, 11444]

Ken,
If you remember the instructions we all read eons ago about casting, you will remember that we were told to place the dipper against the sprue cutter, make the pour and CONTINUE TO HOLD THE LADLE AGAINST THE MOULD for a bit. This it to avoid just what you are mentioning. Now, how many of us really use that technique; I sure don't. I do, though, drop my bullets onto a stack of old bath towels to cushion the blow when they hit the counter. I don't know about voids, but I am certain all my misses originate in the fire control computer (my brain).

[Eggman]

I am relatively certain, relative to someone proving otherwise, that the minie is solid throughout by the time you drop it.

[DAVE FRANCE]

There is heat transfer from the lead to the core that forms the cavity. So that core helps the lead to harden inside by the time it is hardened on the outside. Leaving a lead sprue on the sprue cutter makes it take longer for the whole Minie to become solid, but if you don't leave a sprue to solidify last, you may get a hole in the nose of the bullet. I sometime touch the sprue cutter to a wet sponge to make the sprue harden faster, and it causes no problem.

Sometimes holes are left on the inside of the Minie due to trapped air in the mold. Lead shrinks as it cools, but the amount of shrinkage is not enough to make a big hole.

Old instructions say to leave the dipper against the sprue cutter for awhile, and I always used a dipper to cast Minies until I got a mold that I could use with a bottom pour pot. You can use a steam of lead from the bottom pour pot if you are lucky. It proably depends on exactly how you pour the lead into the mold, how the mold is designed, and who knows what else.

Shooting is very popular in Texas where I live. I have met two people who cast bullets to sale. I hope to see one in action some time.

[Maillemaker]

I would think the only reason you should have voids in bullets is from air trapped in the mold.

Steve

[DAVE FRANCE]

Hello Steve,

Sometimes after if I cut off the sprue to soon, I can see a small hole appear at the nose of the bullet. That is from shrinkage.

I used to think that lead could not leave trapped air in the mold causing a big void because lead is so heavy it would push all the air out. But I was wrong.

David

[Southron Sr.]

Fellas, for the cost of a good musket you can get a "Master Caster" casting machine.

The little critter (casting machine) is only a little over 18 inches high and will allow you to turn out hundreds of bullets per hour-and good as or better quality bullets than you can hand cast.

When you cast by hand, you are using Roman Empire Era Technology. Come into the 21st Century!

[Maillemaker]

Sometimes after if I cut off the sprue to soon, I can see a small hole appear at the nose of the bullet. That is from shrinkage.

I think you are right. I have seen this very rarely when I have not left a big enough puddle on top of the sprue.


I used to think that lead could not leave trapped air in the mold causing a big void because lead is so heavy it would push all the air out. But I was wrong.

Yeah, I can consistently get voids in my bullets if I let the lead pour directly down the hole. I have to cock the mold to one side to let the lead "swirl" into the mold.


Fellas, for the cost of a good musket you can get a "Master Caster" casting machine.

I googled this and am reading, but do you have a link to the one you are talking about?

Steve

[Maillemaker]

Is this it?

http://www.magmaengineering.com/products/master-caster

Looks cool, but it doesn't look like it is fundamentally any different than a hand-held mold block. It just gives mechanical repeatability to the handling of the mold itself.

I'm a little concerned because I get my best minie pours when the mold is cocked slightly. I tend to get voids when mold pours directly in from the top, as this machine appears to do.

Steve

[matt]

Whether using a ladle or bottom pour I dont pour directly into the hole but use the edge of the hole to get the lead in. I find I get less rejects that way form voids or the mould not filling. I also tend to cast hotter which keeps the rejects down also. Lead is puddled onto the sprue plate and when it turns from shiny to duller than it is cut off.
Mack

[Pat in Virginia]

What I have gathered from reading material written by the English/Canadian top level long range shooters of the 1860's and 70's is that as the lead cools it does so from the outside to the inside. The outside forms a hard shell. The lead is shrinking as it cools. Pure lead in .45 caliber will shrink about .005 in diameter according to the NRA publication on bullet casting. So you can expect a void to form on the inside of a bullet. In a normal .45 caliber bullet it's unlikely you will see it. In a Minie you very well may when you look up into the cavity. This effect is probably one of the reasons that the English swaged there bullets and why those bullets were known for their accuracy.

The void if fully inclosed will be a vacumn.

So they say.


Pat

[Bill Weitz]

This should add some interest to the subject. I make trash cans with an aluminum Lee mould. I find that after about ten bullets they will crack open like an egg when they hit the table and the inside pores out. Casting with my iron molds doesn't do this. The trash can shoots really well so I'm not going to give up on it. I usally cast about 8 cans then cast my other bullets while the aluminum cools a little. I have also found that I get more varience in weight compared to the iron cast bullets. I'm using a bottom pore around 750 degrees.

[matt]

Bill,
you arent waiting enough time with the lee mold. Another 20 seconds or so and that will get rid of the problem of them not being solid. I cast very hot that my minnies during a good run start to turn blue when they come out of the mold takes about 45-1 minute to fully solidify. Just remember that with the aluminmum molds they cool very fast and there is a fine point between good bullets and wrinkled misformed ones. Id rather wait a minute than having to get the mold temp up again.
Matt
Winslow's Battery D 1st NY LT Artillery.

[iron brigade]

unless i have the mold right under the spout i get air pockets in the minie's. they are 10 grains lighter by weight if i pour with the mold held lower.

[Southron Sr.]

Dear Maillenmaker:

One good thing about the Master Caster is that IF you want to "set up" the machine to have your bullet mould slightly canted, you can.

I purchased my first Master Caster in the early 1980's and am now on my second machine. As I generally cast 300 or 400 bullets per casting session, I am wondering how many bullets I have actually cast with the Master Caster over the years.

I am also convinced that with a Master Caster that once you know the machine it is possible to cast bullets that are better than you can cast by hand. WHY? Because with the Master Caster, everything in the "pouring cycle" is always exactly the same from bullet to bullet except what you control which is the pour rate of the lead and the length of time the bullet remains in the mould.

[Maillemaker]

One good thing about the Master Caster is that IF you want to "set up" the machine to have your bullet mould slightly canted, you can.

That is good to know!


I am also convinced that with a Master Caster that once you know the machine it is possible to cast bullets that are better than you can cast by hand. WHY? Because with the Master Caster, everything in the "pouring cycle" is always exactly the same from bullet to bullet except what you control which is the pour rate of the lead and the length of time the bullet remains in the mould.

I can believe this absolutely. As in shooting, consistency is the most important thing. Without consistency, you will never have accuracy.

I am also now looking into bullet swaging machines. However, the first response I got said you cannot swage bullets with grooves on the side...not sure I believe that yet.

Steve