Understanding the Hornady Factory Crimp

[Siringo]

Hoot -- I will be there between 3:20 and 3:30.

[Hoot]

Hoot -- I will be there between 3:20 and 3:30.

See you there.

Hoot

[Hoot]

So this theory is totally busted.No sign of any cleaver crimp. Hardly any effect from seating the bullet at all on the case mouth.

Here's a collection of images utilizing different lighting techniques

Sidewall cross section


All kinds of mouth angles






In the first image there is a slight suggestion of a taper. In the second and third images, there is an obvious lack of drag marks within about a tenth of an inch of the mouth, suggesting they expand the mouth ever so slightly and then crimp it back down after seating. In the last image, you can see the lines that some times are visible at the mouth. One member suggested it might be caused by not chamfering the mouths. I'm at a loss to guess what the actual crimping mechanism is. The lack of drag scarring on the outside like a taper crimp leaves might imply they use some kind of rolling action between plates or rollers. Your guess is as good as mine.

Let the speculation begin...

Hoot

[Texas Sheepdawg]

That theory about not camfering the case mouth may be the reason some are
Seeing that "signature". When they make the case and size the OAL
They may not be camfering beveling the case mouth to remove the bur.
This material may present the look we are seeing once the bullet is seated
And a factory crimp applied?
Hmm. So are we seeing what might be a skipped process in a factory load?

[Siringo]

I admit ---- BUSTED!