Monday, January 21, 2019

A crimp experiment

While digging around on black-powder loads a while back, ran across several people saying that instead of a crimp die to lock the bullet in place, they seat the bullet against the compressed powder, then use the sizing die to iron out the bell in the case mouth, which also presses the case against the bullet to hold it solidly.

I haven't tried that with black, but the other day I did try it with smokeless: the Lee 405-grain hollowbase bullet over A5744, five rounds with standard crimp, five using the sizing die.

I got a tighter group with the standard crimp.  Now I need to load some black and try it with those.


Mike said...

It appears to me that the sizing die would swage the bullet too small?

Firehand said...

You run it in just enough to iron out the flare, no further.

Though you do bring up an idea: do this, then pull the bullet and see if it did affect the diameter. If you ran it in very far I'm sure it would, but doubt it will in the 'just enough' amount.

Mike said...

I understand now, you use the sizer like a taper crimp die.
I use a oversize powder thru expander die for soft swaged .45 swc bullets to keep from swaging the soft bullet down in a too tight case. Stops leading and helps accuracy as well. Works like a M die then I use a taper crimp to straighten up the case.
I pulled a few before the change to the oversize expander and sure enough they were about .002 undersize.
Good luck