Roll Crimp or None....

[Craigwood]

This more focused on 9mm. And correct me if I am wrong.....please. Looking at 9mm I have noticed and read that 9mm loads prefer a taper crimp as opposed to a roll crimp. True or False. I have been away from reloading for a few years now. And had opted to get back into it. I retired my older version Lee Progressive 1000 for a more advanced no name mentioned. If you want to know I'll tell ya.
Second. The OAL for a LRN 125 gr. Speers says 1.130.... Max on a 9mm is 1.169. On another 125 gr Jacket Soft Point it requires more of a Bullseye load than the 125 Lead Round Nose. How would one know what OAL to use when a 100 gr OAL could be1.080 and 1.100 with a 125 gr. I guess I will go with 1.130 with my 125 LRN and why? And what determines the more of a powder charge for the same weight bullet? Because of the harder jacketed vs. the all lead to prevent lead fouling with less charge ???

[shooting4life]

Taper crimp on auto cases and roll crimp on revolver cases.

[Craigwood]

Taper crimp on auto cases and roll crimp on revolver cases.

Excellant.....Thanks shooting4

[Craigwood]

Taper crimp on auto cases and roll crimp on revolver cases.

The taper crimp auto vs. the roll roll crimp is because of the pressures? If so why does the 45 acp in most cases require more powder or equal to a 38 spl or 357 mag? Yes the 45 acp is heavier. But why a taper for auto vs. roll. Am I being dumbdee dumbdee here. Or am asking good questions for common sence reloading? I am on the verge of getting a 1911 .45 and reload for that.

[freonr22]

what press?

[Craigwood]

what press?

I got the Hornady Lock n Load Progressive. Check im out.

[shooting4life]

You taper crimp in autos because they headspace off of the mouth of the case and revolvers will head space off of the rim so the roll crimp is ok. The roll crimp can change the size of brass in a way to have te auto cartridge not head space properly. Either crimp works as well as the other taking above into consideration. Even if you roll crimp in an auto you will probably be ok.

[freonr22]

I got the Hornady Lock n Load Progressive. Check im out.

AWESOME! I have one too, no need to be ashamed I have the case feeder also

[XDRoX]

Most revolver calibers should be roll crimped. This is to prevent bullet movement caused by heavy recoil. And it also creates more pressure in hot loads.

Auto loads usually require a slight taper crimp. This is to prevent bullet setback when being chambered.

Don't get carried away with either crimp. Rounds do not require much crimp to do the job. With auto rounds like 9mm and 45, make sure that you are fully removing the bell (that you made in the expander die), but not marking the bullet.

It will take some trial and error to get the perfect crimp. But one perfected your rounds will be more accurate and function better.

[XDRoX]

Also most revolver bullets will have a channel (cannelure) to roll the case into.

[Craigwood]

AWESOME! I have one too, no need to be ashamed I have the case feeder also

You have the case feeder too? awsome. I am wondering why Hornaday does not have a setup as an option simular to the Lee 1000. where you just add a tube. The case slider into station one is as I can see is seperate from the actuctual motorised case feeder.

[Craigwood]

Also most revolver bullets will have a channel (cannelure) to roll the case into.

Interesting observation because I have some leftover 9mm that also have the cannelure channel.

[XDRoX]

Interesting observation because I have some leftover 9mm that also have the cannelure channel.

Are you sure they're 9mm?

[spacecase0]

some people will use the same bullets for 9mm, 380 and 38
I have wondered how good of a plan that is,
but it does seem to work for them

[Tythagoras]

XDRoX has it right. Revolver ammo is crimped to prevent the bullet from moving forward under recoil. Auto ammo is crimped (sometimes) to remove the bell from the expander, and needs to resist being pushed backwards into the case when the cartridge strikes the feed ramp.

It's been said many times here, and bears saying again; neck tension prevents setback problems in autos. Crimping reduces neck tension. That's why, with an auto cartridge, you ideally want to just crimp enough to remove the bell from the expander die, if you use one, and you probably will need to with a progressive press.

I use a single-stage press, so I can get away with just chamfering the case mouth. That may not work so well with a progressive, I use Hornady dies with my 9mm, if that matters. I think there may be some other benefits to flaring just a little, like keeping the bullet seating straight in.