Taper crimps

[Hopalong]

I understand the idea behind the taper crimp but I have a couple thoughts/questions about the process and possible results.
In one post I read, it mentioned the possibility of making the brass thinner if you over-crimp. I can understand how that might happen, particularly with bullets having thicker jackets or are solid copper like what I plan to load. I can see squeezing the brass between the die and a tough bullet. Should you approach the taper crimp process with those sorts of bullet construction considerations in mind? Lighter crimp on "tougher" bullets?
It would seem to me that the brass would have more "spring" than the bullet. When you crimp, the brass' tendency would be to return to its original size/shape, the bullet less so as the lead would more easily compress. Or does the strength/resilience in the jacket keep in contact with the bras?. It must, because taper crimps seem to work, but...
Thoughts?
Thanks.
 
Hop

[Hoot]

I understand the idea behind the taper crimp but I have a couple thoughts/questions about the process and possible results.
In one post I read, it mentioned the possibility of making the brass thinner if you over-crimp. I can understand how that might happen, particularly with bullets having thicker jackets or are solid copper like what I plan to load. I can see squeezing the brass between the die and a tough bullet. Should you approach the taper crimp process with those sorts of bullet construction considerations in mind? Lighter crimp on "tougher" bullets?
It would seem to me that the brass would have more "spring" than the bullet. When you crimp, the brass' tendency would be to return to its original size/shape, the bullet less so as the lead would more easily compress. Or does the strength/resilience in the jacket keep in contact with the bras?. It must, because taper crimps seem to work, but...
Thoughts?
Thanks.
 
Hop

That point has come up before. I thought that pre-shrinking before seating the bullet would be one approach to avoiding the springback and that was the impetus behind my TightNeck thread. Keeping the pre-shrinking symmetrical with no mandrel inside the neck, or other method of precise registration poses a challenge with that approach.

That same springback is why we generally don't encourage using the expander die that Hornady includes, prior to seating.

So yes, you have to exhibit some restraint with the degree of taper crimp applied when you're not driving it into a cannelure or in the case of Barnes, the driving band groove. With careful annealing and sizing technique, you can mostly iron out crimp scars, but you can not un-shrink the mouth an over applied taper crimp to a contiguous bullet surface and worse yet a monolithic bullet. Those cases where that happens wind up being put into the bin for loads that employ a stab crimp since it is applied further down the case. That method of crimping opens a whole other can of worms, but I won't get into that again.

You will typically see me write of using a .476 taper crimp to a 250 FTX for that very reason, while applying a more aggressive .474-.475 to either the 200 or 225gr FTX since they have cannelures lower than the adjoining surface to drive it into if you seat them so that the cannelure is at the mouth. With heavier, cannelured bullets, that sometimes robs you of valuable case capacity due to a lot of the bullet being inside the case to get that cannelure down at the mouth. For bullets that have two, I have tried hitting the rear-most cannelure to get around that, with less than stellar accuracy due to its proximity to the heel of the bullet. Don't mess around near the heel. It's that last thing to touch the bore.

All of this is not intended to make reloading sound overly tedious. Lot of good results can be had without damaging degrees of crimping, or exotic techniques by simply matching the bullet weight and powder more prudently. I unfortunately am drawn like a moth to a flame, to stretching the comfort zone in the interest of finding the occasional truffle. All of this is as much in the interest of enlightenment, as practical application. It keeps my signature relevant.

Hoot

[Hopalong]

Hoot-

Sigh… One of these days I'll be able to quit reading and actually start reloading.

Seriously, thanks.

Hop