IF you're setting the die up so it barely touches then when under loading pressure the whole setup, dies, bushing, ram arms and even the press all will stretch or deform just very slightly. But if you're only looking for that last couple of thousandths it can add up to a tight bolt.
What you gain by turning the die down another quarter or half turn so that the ram can't quite get up to top dead center is the ability to remove that flex and be sure you're fully closing up on the die with the shell holder.
As H4831 says too you're shooting yourself in the foot by screwing it down past where there's about a quarter to half turn of "interference" at the top. You lose your lever and arc of the arms mechanical advantage. So set it to where it touches lightly then try a half turn more. I'll bet that fixes it.
If not then you need to shave down the shell plate or nose of the die.
If there's numbers stamped on the surface of the shell plate that the sizing die hits use a sharpening stone or sandpaper on a flat surface to remove any raised burrs. That alone might be your tight bolt issue if the numbers are deeply stamped and turned up a tall burr.
If you need to remove more then use the same sharpening stone or oiled sandpaper to hone down the nose of the die in small amounts until it works.
This is NOT the time for a grinder or even a power sander. One touch on either might remove way more than you need or planned on removing. Go slow with the hand method and work into it.
What you gain by turning the die down another quarter or half turn so that the ram can't quite get up to top dead center is the ability to remove that flex and be sure you're fully closing up on the die with the shell holder.
As H4831 says too you're shooting yourself in the foot by screwing it down past where there's about a quarter to half turn of "interference" at the top. You lose your lever and arc of the arms mechanical advantage. So set it to where it touches lightly then try a half turn more. I'll bet that fixes it.
If not then you need to shave down the shell plate or nose of the die.
If there's numbers stamped on the surface of the shell plate that the sizing die hits use a sharpening stone or sandpaper on a flat surface to remove any raised burrs. That alone might be your tight bolt issue if the numbers are deeply stamped and turned up a tall burr.
If you need to remove more then use the same sharpening stone or oiled sandpaper to hone down the nose of the die in small amounts until it works.
This is NOT the time for a grinder or even a power sander. One touch on either might remove way more than you need or planned on removing. Go slow with the hand method and work into it.


















































