Well, I wasn't paying close attention and let someone slip in an order for what appears to be a 30 caliber airgun bullet, cast of 30:1 alloy.
As has been discussed on other posts, the force of cutting the sprue distorts the bullet base. My sprue plates are not designed for the combination of 30 caliber and black powder alloy (on the other hand, 30 caliber and wheelweight is no problem, since wheelweight sprues cut easily).
Here are the measurements of the base with 30:1 alloy. The spec is supposed to be 0.306" - 0.308":
We have a 0.0041" spread. Lotsa luck shooting that bullet.
The cavity is machined correctly, it's just that the sprue cutting force is pushing the base to one side, resulting in a pronounced egg shaped base. The only solution would be to make a custom sprue plate with itsy bitsy sprue holes, and that's not gonna happen.
If you think making custom sprue plates is quick and easy, THEN YOU DO IT
! ! !
This mold will be shipped out this way. I don't feel responsible because my job is to machine the mold correctly, and I did that. I have no sympathy with the problem. This subject has been discussed over and over......... it may be that the only solution is to eliminate all alloy choices except wheelweight.