A friend of mine called me asked why a 200 grain cast bullet was weighing only 160 grains after it was cast. I replyed the metal might be made from Babot and you could identify it by looking for bullet deformity " creased bullet" from the mold. I also told him the metal may have a high tin content which would cause the bullet to be light. Actually hard bullets are usually lighter.
The last problem could be either a cold mold or low temperature of the alloy which would cause the bullet not to form in the mold. The crimping and lube groves would not be well defined from low temperature of the mold or metal.
Again this post is for your information. There might be many bullet casters in this Forum but it may help some of you.