Case mouth issue

[cmahoney]

I picked up a carbide Sinclair expander mandril and started using it on once fired Lapua brass. The brass is building up and creating a rim around the case mouth. Any ideas?


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[tdot]

This is a complete shot in the dark. But have you checked the overall length of the case? That looks like it might need to be trimmed to length.

Or possibly a resizing die that is hitting the mouth of the case.

My guess is that the Sinclair mandrel is only pushing the imperfection to the outside.... unless of course the case is being run too far up into the Sinclair die and it is deforming the end of the mouth slightly.

All guesses.... good luck

 

[WestexSBK]

If your cases do not have this flare before expanding then It looks like you are contacting the the top of the Sinclair die on your upstroke.

When setting up your expander die raise a case all the way up. Remove the expander mandrel and screw the die in until is contacts the case and then Back off 1/4 turn

Joe

 

[cmahoney]

Thanks guys, I think I damaged the cases on my Redding FL size die with the competition shell holders.


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[deerkiller]

Thanks guys, I think I damaged the cases on my Redding FL size die with the competition shell holders.


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If you set the ram depth with the .02 holder then started with the .10 you probably did (that's backwards) but if you began correctly there is really no way that could be blamed on the shellholders
what I see in the pictures is cases that need to be trimmed so if they're brand new then what WestexSBK says sound correct