Brass is getting crushed when I try to resize it?

[Wisconsinner]

Hey all, I am using forster 6mmbr rem dies, trying to run the mandril down the new lapua brass I got, and it does nothing but crush the brass. I used the die to resize once fired brass just fine. What am I missing? Any help is greatly appreciated, It is hard to throw .90 cents away each time....

 

[BoydAllen]

My memory may be off on this, but here goes. Forster dies have their expander balls mounted high so that the bottom of the neck begins to expand while the very top is still coming out of the neck portion of the die. This is to help case runout. The problem that you may be running into is that the friction of the expander may be adding to the force it takes to size the neck down smaller as it enters the neck part of the die, collapsing the shoulder from the total load. Also, not all expanders are shaped to work well bottom up. The best way to handle this is to use an expander die and mandrel, like you would use to prep cases for neck turning. Forster will lap out the ID of the neck part of their dies for a small fee if your necks are being sized excessively before or in this case after expanding. Like I said, this is all from 20 year old memory, so it may be worth exactly what it cost. If you can lower the expander , reshape and polish the bottom contour, it might be made to work. Just remember to set the die high enough so that the mandrel does not run into the bottom of the case, and put everything back were it is supposed to be once you have done the necks of the new cases. Beyond this, you need to be lubing the inside of the necks and making sure the chamfers are right.

 

[amlevin]

Are you using a mandrel die or a sizing die? If you're using a sizing die and the expander is too high it will get bound in the neck by the sizing portion of the die. On a brand new case, where the neck is already sized, you may be catching an edge with the bottom of the expander "ball". Some dies use a tapered expander that slides into the case neck with ease and others have a lip that can catch. If one's not careful------ well, you know the rest.


If it's a separate mandrel die then perhaps you aren't lubing correctly ???? For new case prep I use a Sinclair Mandrel Die to make sure necks are round and of the proper size. No sizing portion to interfere and you only have to adjust so the shoulder on the mandrel doesn't contact the case mouth. You DON'T adjust a die like this until it touches the shell holder. Just enough so that the full diameter portion of the mandrel extends through the neck. Easy to see if you mark up the mandrel with a sharpie then check it after the first case. Adjust accordingly.