Minie ball weight difference

[Maillemaker]

I have come to the conclusion that the best way to get consistent weight bullets (and thus probably voidless) with hollow-cavity bullets is to ladle-pour them.

There was an article reprint by David Francis not so long ago in the Skirmish Line that talked about doing load workups and weighing bullets, and how much variation would result in how much drop at 100 yards. I can't remember the stats now.

Steve

[Hal]

I have had the same results. I once read on the CAST BOOLITS site that you get more consistent weights on anything greater than about 400 grains if you ladle pour. I tried it and have to agree. Why? I'm not sure. I suspect it has to do with tilting the mould and rotating back level while pouring.

I have three pots. Two of them, I have removed the bottom pour mechanism from because I never used it, it was in the way of ladle pouring, and it leaked. I might do the same to the third one one day, but I seldom use it, so it's not a problem right now.

[PoorJack]

While some get better results by ladle pouring, I get very consistent results with a bottom pour Lee 4/20. I've drilled out the nozzle by about .020 and run it hot. I've found the key to consistent weight is pour fast and hot with a consistent tilt on the mold. Also allow the pour to continue with a generous size sprue puddle. In every pour, you'll see that dimple described earlier as the lead cools. Don't open the mold till you see it. I also visually inspect while casting and those with obvious flaws go straight back into the pot. If the mold is at operating temp, there are usually very few of those.

With the mold at operating temp, I get a variation of about+/-.5gr. There are a very few outliers and those are culled.

One other thing I've noticed about bottom pour pots, the amount of lead in the pot can affect that quality. I keep my pot at least half full all the time. I think this variable is why some find ladle pour more consistent.

[Carolina Reb]

I also open up the nozzle on my bottom pour pots and run them hot. When they start to drip it's time to clean the pot. When you put it back together after cleaning, lap the end of the shutoff pin with valve grinding compound or JB Bore lapping compound just like you would for small engine valves. One of my pots is 30+ years old and still casting accurate bullets.

The secret of success, whether you use bottom pour or ladle, is familiarity with your equipment.

[michael noble]

What is a good operating temperature? I usually run between 750-800.

[BLakatos]

What is a good operating temperature? I usually run between 750-800.

I?ve found my mould cast best between 820 and 850. Too many voids and throw backs if less

[Kevin Tinny]

Hello:
I have best casting weight with dipper pressed against sideways sprue plate; then rotate both to fill.

Pot metal temp of at least 775F, measured with Rotometals dial immersion thermometer. Not expensive. Pot dials inaccurate. Pre-heat mould and sprue plate by slight immersion in full temp pot. Add metal after only 1# used to reduce metal temp drop and delay that cools mould. Let ladle excess flow over top of sprue plate to elim shrink below sprue plate and to keep sprue plate hot. All this and lots more proven stuff in NRA's "Cast Bullets" Handbook. Smiles.
Kevin Tinny

[PoorJack]

What is a good operating temperature? I usually run between 750-800.

I set my Lee 4/20 to wide open. Highest it will reach is a tad over 900F but when casting, it will dip to about 850F as I toss my sprues back in as part of the process.

[Hal]

I think the general consensus on castboolits.com is 100*F above the liquidus temperature of whatever alloy you are pouring. If you are not familiar with the term liquidus temperature, it is the point at which you are changing phases from solid to liquid. Essentially, your temperature will rise steadily as the solid lead warms. Then just as it begins to melt and give you that thick gooey consistency, the temperature will plateau and remain at the same temperature for a while until the lead is melted, and then the temperature will begin to rise again. That plateau is the liquidus temperature. For pure lead, I think that is in the 625-650*F range. I usually cast pure lead at 750*F and harder lead at 800*F. The hotter it is, the more it wants to oxidize and give you that nasty dross on the surface that you have to keep pushing to the side when ladle pouring. That is where the bottom pour pot has an advantage.

[Maillemaker]

I cast about 875F. I know I'm in the right range when the bullets start turning blue when they are cooling off.

Round ball you can get away with lower temps.