Need Bullet Help(?)

[Boge]

I think that I have bullet trouble or maybe something worse.  :shock:  I have a bullet that is giving me fits when reloaded in fired cases! Many times the bullet will not stay put after crimping as it will spin loosely in the case. For example, yesterday I loaded 25 brand new cases and never had a problem. Loaded like magic! Today, after shooting these I tumbled and decide to reload a few. Well, I barely belled the mouth and almost all will freely spin in the case as well as some will almost pull completely out of the case! I torqued down the crimp as well as full length resized the loaded rounds and still the same problem! I cast these bullets from a custom mould that is dead nuts on. The bullet has a huge long lube groove and the base is only 0.090 thick. The crimp groove is not real deep. They cast perfecftly at .512 which is my groove diameter. The only thing I can think of is that the case body has fire formed a hair beyond .512 and that coupled with the fact that the bullet has little bearing surface and a tiny crimp groove the bullet has little purchase area, hence only the skimpy crimp groove is making contact and that is not enough to hold the bullet. If that is the case then my only solution is to have the mould enlarged say a thousandth or so (if the chamber permits!) or have Lee make me a special factory crimp die (if they will for .50 cal.). Opinions?

[Leftoverdj]

Sounds like you need thicker brass or a tighter sizer.  Depending on what you are using for alloy, you may be able to get slightly larger bullets by going to an alloy with a higher antimony content.

It's also possible that your expander is a bit oversize.  Size a few and bell them by some other means to see if the expander is the problem.

[The Shrink]

What are you loading with and shooting in?  

If you're loading black and shooting in a single shot those loose bullets are no problem at all as long as they stay in the case.  

If you are loading smokeless, and the cases are resized, then your expanding ball is overly large, expanding the cases too much.  If so, you can either send it back to the manufacturer or turn it down yourself, a little at a time, with a drill motor and a little 400 grit wet and dry paper.