Crimping handgun loads - YES or NO???

[Mikej]

The small amount of expansion (bell) you put in the mouth of the case on 9mm .40, .45 is barely enough to feel a difference between that and an UN-expanded case. If you feel that difference, tightness/binding/resistance at the top of the stroke you've got your crimp! From what you are saying it sounds like you are thinking of a "Roll Crimp" like is used in .38, .44, .45 Colt. If you are seeing a bevel on a 9mm at the top of a case there's a problem. The case mouth is what the round headspaces on, it's important that the mouth of the shell be "Crisp" for lack of a better term.
I suggest, to help you grasp the concept of a taper crimp, you sacrifice a case and, possibly, a bullet. Put a bullet in a dummy round and keep going with the crimp until you fold a case so you get an idea of just how far you can push it before there's (Safe) damage. You do have a bullet puller don't you? And, I keep a small magnifying glass on the bench, comes in handy for all kinds of things.

Mike

 

[joken]

I haven't read all these posts. A couple other things. Brass is different so if you set up your crimp for one mfg it might be too much or little for another brand. You can sort your brass or do it by feel like I do. Also make sure your rounds will chamber properly before you load up a bunch. Ken

 

[deadshot2]

If you are seeing a bevel on a 9mm at the top of a case there's a problem. The case mouth is what the round headspaces on, it's important that the mouth of the shell be "Crisp" for lack of a better term.
I suggest, to help you grasp the concept of a taper crimp, you sacrifice a case and, possibly, a bullet. Put a bullet in a dummy round and keep going with the crimp until you fold a case so you get an idea of just how far you can push it before there's (Safe) damage. You do have a bullet puller don't you? And, I keep a small magnifying glass on the bench, comes in handy for all kinds of things.

Mike

Another method which is more precise is to measure the thickness of the case at the mouth, double that amount, add the diameter of the bullet, and that is the measurement you should see when properly taper crimped.

Example, you measure the case thickness and it's .010". Twice that amount would be .020" and when added to the average 9mm bullet diameter of .356" your case should measure no less than .376" OD at the case mouth with a bullet seated.

Because case thicknesses can vary as well as bullet's (lead ones are different than jacketed as a rule), measure for each different bullet/headstamp combination.

 

[davidandreap]

If the case is straight it is right. If it has a bell or a recess crimp at the top of the case it is wrong. It is that simple.

David