Crimping

[KRM45]

The previous post about a crimping die has got me thinking. I've only been reloading for a short time, but I'm not crimping anything.

I've only loaded .45 ACP, but I bought the dies for 9mm and I am saving my brass to start loading .38 and .357. I think I understand the importance of crimping the rounds for use in a revolver, but can someone explain to me the need for crimping the 9mm or .45?

Thanks in advance for your input.

Keith

[Crossfire]

The importance of crimping depends on what kind of gun you are loading for. If you are loading for a Glock, with a barrel which tips down during cycling, it is less critical.

If you don't crimp and you are loading for a semi-auto that has a fixed barrel, then, as the cartridge chambers, the bullet can be pushed back into the case as it hits the feed ramp. This causes higher pressures which can be critical.

I.E., makes a big kaboom instead of a bang.

[cyphur]

What would that mean for say a 1911? 3" specifically, ramp on the barrel.

[KRM45]

The importance of crimping depends on what kind of gun you are loading for. If you are loading for a Glock, with a barrel which tips down during cycling, it is less critical.

If you don't crimp and you are loading for a semi-auto that has a fixed barrel, then, as the cartridge chambers, the bullet can be pushed back into the case as it hits the feed ramp. This causes higher pressures which can be critical.

I.E., makes a big kaboom instead of a bang.

That make sense... Is it good practice to crimp no matter what gun I'm using? If so, why don't the Lee die sets just come with a crimping die?

Thanks for your help!

[nuparadigm]

What would that mean for say a 1911? 3" specifically, ramp on the barrel.

"People sleep peaceably in their beds at night only because rough men stand ready to do violence on their behalf." This quote is by George Orwell.

On the crimping for a 1911: it's a good idea. Also, since the .45 ACP headspaces on the mouth of the case, it's also a good idea not to put excessive crimp on the round. Dillon's crimp die works well in their set-up. If you're not using a Dillon machine, I'd suggest a Lee Factory Crimp Die.

[DustinB]

Is it good practice to crimp no matter what gun I'm using? If so, why don't the Lee die sets just come with a crimping die?

Thanks for your help!

You should always crimp your bullets. Not only does it help with keeping the bullet from moving under recoil/chambering, it helps keep the bullet in place long enough to get proper ignition.

The Lee 3 die sets have the seating die that has a crimping section in it, this seats and crimps in one operation. The 4 die sets have an extra crimping die that post-sizes the case and crimps the bullet. The reason I use a separate crimping die is because my press has 4 stations, with this press it is recommended to separate the crimping and seating process.

[Houston1944]

There are two different types of crimp for handguns, roll crimp for revolvers and taper crimp for semi-autos. Revolver bullets have a cannalure (fancy name for a groove) that allows the crimped brass to "roll' into the groove and help hold the bullets in place while sitting in the cylinder. Semi-autos utilize a taper crimp whose only purpose is to remove the "bell"from the case. Bullet setback is prevented in semi-autos by case tension, not by the taper crimp. If the taper crimp is "over-crimped" it can buckle the case slightly and actually contribute to bullet set back.
In answer to your original question yes, you should crimp all handgun bullets. Semi-auto rifles aslo require a roll crimp, but it is optional if you are loading for a bolt action rifle. All my rifle loads are for bolt action and I never crimp them.

[KRM45]

The Lee 3 die sets have the seating die that has a crimping section in it, this seats and crimps in one operation.

Thanks for all the help on this...

I hate to show my ignorance again, but if I am using the seating die from the 3 die set does that mean I am already crimping?

[lrb111]

The Lee 3 die sets have the seating die that has a crimping section in it, this seats and crimps in one operation.

Thanks for all the help on this...

I hate to show my ignorance again, but if I am using the seating die from the 3 die set does that mean I am already crimping?

There are more of us benefitting from the Q&A. So, if you don't ask, someone else will have to.

I'm going to start reloading, but right now i have a box of .45 taht won't feed half the time. The cases seem to be lacking any kind of crimp. Really ragged edges.

[DustinB]

It depends. You have to adjust the die to crimp. The way I adjust the Lee seating/crimp die.

Grab a case and a bullet. Bell the case mouth in the 2nd die.
In the crimp die: Run the ram up with the case in it.
Screw the die down til it touches the case.
Back it out a turn or 2.
Back the seating adjustment knob out a good bit.
Sit the bullet on top of the case and run the ram up.
Check the overall length.
Screw the seating adjustment knob in.
Run the ram up.
Check the overall length.
Repeat until the overall length is correct.

Now to set the crimp:
Back the seating adjustment knob out a good bit.
Raise the ram with the shell you just made.
Screw the die in until it touches the case.
Lower the ram and screw the die in another 1/2 to 1 turn.
Run the ram up and down.
Look at the edge of the case mouth and check to see that the bell is gone.
If not screw another half turn and raise the ram again.
Repeat until the bell is gone.
Once the bell is just gone I normally go in another half turn to get a slight crimp.

Once the crimp is set run the ram up into the die again.
Screw the seating depth adjustment knob down until it touches the bullet.

Your seating/crimp die is now properly adjusted.

Don't feel 'ignorant' for asking questions. Feel free to ask. You don't start off knowing everything, only way to learn is to ask.

[KRM45]

Wow, that's a lot of great information. I'm going to print that and work on this in the morning.

I've just been adjusting for OAL without checking for crimp. It looks like I have about 250 rounds sitting on the shelf I need to run through the press again!

You guys are great!

[KRM45]

Ok, I have re-set some of my dies. In checking them and looking back at the directions that came with them, I have concluded that they were properly set in the first place. This settles a lot of concern I had about the rounds I had already loaded.

I also learned that understanding why something is done is a lot better than simply understanding how it is done.

Thanks for the help!

[cyphur]

What would that mean for say a 1911? 3" specifically, ramp on the barrel.

"People sleep peaceably in their beds at night only because rough men stand ready to do violence on their behalf." This quote is by George Orwell.

It has been attributed to George Orwell in many cases, however there is some controversy over whether he was quoted someone else at the time.

As I cannot find a definitive answer to it, I leave the quote as UNK.

If and when I do find a reliable source that attributes the quote to him, I will start crediting it to him.

[Patriotswrath]

The Lee 3 die sets have the seating die that has a crimping section in it, this seats and crimps in one operation.

Thanks for all the help on this...

I hate to show my ignorance again, but if I am using the seating die from the 3 die set does that mean I am already crimping?

Ignorance is better defined by not knowing and rather than asking blowing your gun, hand, or face up.

Not knowing and being willing to ask for help seems far removed from ignorance.

[TX Rancher]

For a consistant crimp be sure to size your cases all the same...