.40 S&W, to crimp or not to crimp?

[Iron Sighted]

So I just bought my first pistol and thought I'd get started reloading for it while I wait for it to arrive in the mail.

My question for everyone is whether or not i should crimp my rounds when I'm done loading them up? I've heard people say don't crimp because the cartridge headspaces off the case mouth so it isn't a good idea, also heard many people do crimp with no issues , not sure who to believe, though I'm inclined to go ahead and give a light crimp. I'm using a Lee carbide 4 die deluxe set that includes the "factory crimp die", if that makes any sort of difference.

I'm probably making too much out of a minor issue, but thought I'd run it by all you old pros anyways, thanks for any help you can throw my way.

 

[TACTICAL111]

I always use the Lee post sizer/crimp die.

I chamber every round off the slide release for speed, so I must ensure that my rounds chamber freely every time.

For me, it's paramount, as important as any other step. This is with a G34 which would probably chamber a buffalo.

I'm probably making too much out of a minor issue

You're not.
My match grade 1911 would not chamber a non post sized round....period.

 

[Silverback]

I use a taper crimp die which just straightens the mouth of the case back parallel to the bullet. I use one for 9mm, 45 ACP and 40 S&W and I have never had a problem with feeding in any of my pistols in the past 25 years that I have been using them.

 

[ben hunchak]

You must use a taper crimp on these rounds.

 

[tjhaile]

At the very least, you will need to use either the crimping shoulder in your seating die or your Factory Crimp die to remove the belling of the case mouth that you did prior to seating the bullet.

Maximum case mouth diameter for .40 S&W is .423". You will likely want to go just a bit smaller to ensure easy chambering. An excessive taper crimp will distort the bullet.

 

[Ganderite]

Crimp enough to take off the flared mouth. It has to headspace off the case mouth, so don't over do it.

 

[Iron Sighted]

Thanks everyone

 

[Skyhawk]

From a past mistake I did, I learned not to depend entirely on sizing the case mouth with micrometer or calipers either. This is especially important with over-sized lead bullets. To avoid further mistakes, I always pull a bullet after seating and compare its diameter profile along its entire length with a virgin bullet. They should be the same.

With tapered bullets, you don't have to bell the case as much to accept the bullet. The diameter of the belling can easily be a few thousandths under the maximum base diameter of the bullet. With this configuration, there is no bell to remove and no crimp is necessary. The brass is already stretch to the exact size of the bullet - including the case mouth. When using those bullets, I just back off my crimp die until it's a no-op.