Author Topic: Newbie question on large bullets (Read 740 times)

AllenRead · « **on:** December 29, 2003, 06:28:55 PM »

I just cast my first 50 cal, 320 gr REAL bullets from the Lee mold. Some of the bullets had a bubble hole in the base.

Naturally I then read Lees instructions that said All large bullets acquire a void in the center, due to the metal shrink when cooling. This can be reduced and centered if the mold is filled in a level position.

Is this a common situation? Is there a better way to avoid the void?

Im sure that this void wont help accuracy.

Thanks

Cat Whisperer · « **Reply #1 on:** December 30, 2003, 06:46:31 AM »

Two things that can be done. The alloy can be mixed (like lineotype) that shrinks less than others - trade off is that it has a LOT of tin and gets very hard; secondly, leave a large puddle of alloy on top of the sprue cutter - it will be pulled into the bullet as the alloy cools - taller is better.

Ross · « **Reply #2 on:** December 30, 2003, 03:46:55 PM »

Also I usually find the hotter the melt the larger the carrot (cavity).
Cheers from Darkest California,
Ross

JBMauser · « **Reply #3 on:** December 30, 2003, 06:29:40 PM »

Do not trade softness for shrink. Stay with lead or close to it which is what the REAL bullet is designed for and accept whatever shrink you get. This bullet is supposed to deform or objurate on ignition anyway. Cast it soft, over flow the mould and lube them and stuff them then fire them. JB

AllenRead · « **Reply #4 on:** January 01, 2004, 10:07:51 AM »

Thanks for the info!

HWooldridge · « **Reply #5 on:** January 02, 2004, 10:07:05 AM »

If using a ladle, leave it in place on top of the mold so the bullet can draw from the melt in the ladle. I turn the mold parallel to the floor, place the ladle nose on the sprue plate and roll the whole thing 90 degrees to fill the cavity. If using a bottom pour pot, keep the sprue plate against the nozzle and then pull away slightly to leave a little puddle on the sprue plate. The bullet shrinks and will pull some material in to fill the void if the gate is not already frozen. Hotter bullets shrink more but the mold needs enough heat so the sprue does not freeze prematurely. Pure lead shrinks more than alloy with the rate of shrink proportional to the type of alloy and percentage of lead in the melt. I cast long rifle bullets and these practices work for me.

Flash · « **Reply #6 on:** January 10, 2004, 10:37:26 PM »

OVERFILL YOUR MOULD!! Make the shrinkage leave the dimple in the sprue, rather than the bullet itself. Leave a reasonable amount on top of your mold by overfilling it a bit. Don't place the nipple from a dipper up against the sprue plate and pour. The same goes for a bottom pour furnace. I let a dime size piece collect on the sprue plate and get a perfect bullet every time.

jgalar · « **Reply #7 on:** January 11, 2004, 03:44:46 AM »

I agree with flash. I recently received and have used the REAL mold. I use a dipper for casting. I found overfilling the mold and letting it set a little longer than other molds before cutting the sprue eliminates the problem. I also let the mold get hotter than other bullet styles.