Problems loading 375 Winchester 250 Cast

[greatwhite]

Having lot's of issues reloading 375 Winchester Cast. I have 250 grain Powder coated bullets. I have run the brass through the expanded but I cannot consistently get the bullet to seat to COL 2.56, 50% of the time the brass crumbles. What am I doing wrong

 

[Polish-Jack]

What size is the expander button?

 

[Snider shooter]

Your expander is probably meant for 375 bullets. Your cast are probably larger. Or your not running your expander deep enough. I made my own expander for loading 375 Winchester and 38-55 with cast bullets. It’s diameter is 0.378. I was getting lead shavings with the Lee expander.

 

[yomomma]

Try Lee universal flaring tool

 

[boxhitch]

If the die is set too low it will be trying to crimp the case, and possibly too soon if the crimp is done before the bullet is seated completely
May only happen on too-long brass if they are not all the same

A slight flare with a Lee die has worked for me

 

[Big bore dinosaur]

Is your brass all the same length.
Over crimp on the longer brass , Will crinkle the side walls

 

[WhelanLad]

Try Lee universal flaring tool

this . plus a lee factory crimp die

 

[Alex McKr]

Have you measured the diameter of your powder coated bullets? Were they resized, after powder coating?
Also, was the bullet seating die set up to crimp in the same operation? As boxhitch already suggested, it may be misadjusted, causing the high failure rate. In which case, seat bullets and crimp in separate operations. Does require some minor die resetting, but, better than 50% ruined cases.
A Lyman . 375 M-die might be something to consider, too.