[b/smith]

know the title was general but the question is when i cast my bullets and inspect later
on some there is a hole in the core of the bullet ( the side where the base plate slides
across) the base. In most its not deep but some are. Am i doing something wrong or is the
nature of the beast ? And can they be shot ?

 

[unclenick]

You are likely cutting the sprues off too soon or else are not pouring enough extra metal in. The tapered sides of the hole in the sprue cut-off plate should be filled to overflow or just-about-to overflow. The blob of metal on top of the fill hole will grow an indentation in its middle as the metal cools. That indentation is extra metal supplied to the mold cavity as the bullet inside shrinks. It's purpose is specifically to fill it in to avoid leaving voids. Once that blob is hard, you can cut off the sprues. If the blob shrinks below level with the sprue plate, you haven't added enough metal or may need to keep it flowing as the bullet starts to cool inside the cavity.

You can shoot bullets with voids in them. They are typically less accurate both because the bullet weight is not a match to the better filled bullets you have, but mostly because the voids are not usually exactly centered, so they introduce eccentric bullet wobble in flight, as they cause the bullet to spins out of balance.

 

[b/smith]

I am leaving plenty of overflow but i am doing it in about 10 to 15 seconds thats probably
to soon

 

[unclenick]

That will do it. If the metal isn't hard enough it kind of tears out of the bullet rather than shearing off. Everyone who learns to cast has experienced this somewhere along the line.

 

[ribbonstone2]

Does sound like the plate is just teraning the base at the center, but there is another type of void we sometimes get.

I've noticed it when the mold is a little cool...still casts a good looking bullet, and often can't see a thing wrong with the base, but they come in a bit light if weight checked. Mosted noticed with the intricate designed bullets ile the loverin style, which have a lot of contact area and sharp edges. Once the mold is hot (hot enough that it takes a good 10-20 seconds for the lead to solidify enough to strike the plate) the bullets weight is normal.

So I sectoned some of the great looking but light weight bullets cast when the mold was not quite up to temp, and found an odd vertical "crack" running up the center of each bullet.


On a guess, the lead cools fast and shirnks, the "puddle" on the plate soldifing as well, leaving that crack. Get the mold hotter, and the puddle stays liquid long enough to feed the shrinkage before the bullet goes solid.

The good news is that the "crack" (or shrinkage void) is central and does little to unbalance the bullet, so if they look good and are light, will tend to keep them seperate and use them for plinking.

 

[scott0116]

What alloy are you using? If it's linotype or harder metal you are going to have the "tears" in the bases. The only other reason for it as has been said is cutting the sprues too soon or letting the mold get too hot. I don't reject any bullets like this, i do segregate them though.

 

[Forest Punch]

pits in base of bullets

well I might get into trouble or this but here goes. over on castbullets fourm there is a man that sales a product called bullplate lube cost $2.50 a bottle his email address is [email protected] now having said that I have been casting using this product for the last 5 years and I have very few tears in the base of my bullets this stuff works I have had the same 2 small bottles of it and I don't think I have used more than 1/5 of a bottle yet this is the cure for the problem you are having Forest Punch

 

[Doc J]

know the title was general but the question is when i cast my bullets and inspect later
on some there is a hole in the core of the bullet ( the side where the base plate slides
across) the base. In most its not deep but some are. Am i doing something wrong or is the
nature of the beast ? And can they be shot ?

I agree. perhaps your mold is to hot and your not giving it time to cool

 

[Ole1830]

Check out a product called "Bull plate sprue lube".

If you follow the directions, it will help with base cavities and sprue smears.