I own the Holiday in Express so here is my 2 Million!!!
Case crumpling/crushing is caused by one of two things;
1.
Trying to seat and crimp the bullet to deep.Let me explain...
When roll crimping and seating in the same step, many folks fail to adjust the roll to the longest case they have. This means measuring all of your cases and setting the crimp to the longest one. Why? Because if you set the crimp for the shorter case, the roll is forced into the top of the crimp groove and has nowhere to go but down, crumpling like an accordion! Soft lead can be more forgiving not not hard lead. This can still be an issue when crimping separately. Make sure when roll crimping that the crimp is set for the longer case. It doesn't take much.
2.
Trying to seat a fat bullet into a narrow holeLet me explain...
Trying to shove a .429/.430 bullet in a case mouth not properly bellowed and or trying to shove same into a neck resized for a .4255" Winchester JSP bullet will crumple the case. In order to accomplish such a task requires dilagence but often results in crushed case mouths and or bulges in case necks.
Over bellowing the case mouth overworks the brass and can cause splitting problems.
If the mouth is not properly bellowed, sometimes the case mouth stretches when the seating process is started BUT as it passes the first grease groove, it shrinks back down cuts into the following driving band, shaving the side of the bullet and then crushing the case mouth.
The
Lee 3 die set resizes the case necks to the smallest diameters in my experiences.
RCBS "Cowboy" dies resize case necks to better fit the larger .429/.430 bullets thus an exaggerated bellow is not needed, increasing case longevity.
The Lee FCD "squeezes" the neck to mimic Winchester's factory crimp from years ago. However, the die is set for .428" bullets. Trying to over squeeze this step on larger bullets can damage the case and is were I experienced 99% of my half a dozen case mouth splits.
Most commercial cast lead bullets are NOT true 44-40 "profile" bullets. A true 44-40 profile bullet has a continued curving O'give. If such a true 44-40 bullet is used, the far more superior crimp die is the Redding 44-40 Profile crimp die. This die is a MUST when used on bullets without a crimp groove or on Winchester/Remington JSP bullets.
Explanations and photos here:
https://sites.google.com/view/44winchester/handloading?authuser=0https://sites.google.com/view/44winchester/handloading/crimpingcrumpledbuckled-case-issues?authuser=0https://sites.google.com/view/44winchester/handloading/redding-profile-crimp-die?authuser=0