9mm crimp?

ghost2vp

ghost2vp

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Hi,

I know I am beating a dead horse here but...

Two questions about 9mm reloading, both involving a single stage press...

1. Is it required to flare the mouth of the case for seating or is that just for a progressive press?

2. If you are not flaring the mouth of the case, do you need to crimp?

I hope I am not irritating anyone with this question that has knowingly been asked a million time.

Thanks all,

Ghost2vp.
 
ghost2vp said:
Hi,

I know I am beating a dead horse here but...

Two questions about 9mm reloading, both involving a single stage press...

1. Is it required to flare the mouth of the case for seating or is that just for a progressive press?

2. If you are not flaring the mouth of the case, do you need to crimp?

I hope I am not irritating anyone with this question that has knowingly been asked a million time.

Thanks all,

Ghost2vp.
Click to expand...

The purpose of flaring the case mouth is to allow the bullet to seat in the case without distorting the case mouth or collapsing the case wall. It must be done regardless of the type of reloader.

To answer your second question: Since you have to flare the case mouth- yes, you have to crimp it.
I prefer a taper crimp for a number of reasons. You should look into that if your die only has the roll crimp.


PS: It's better to ask than proceed and ruin a bunch of loads. :D
 
I would only add that both flare and crimp need to be as minimal as possible.

Just enough flare to seat a bullet on top of the case without it falling off, and just enough crimp to get rid of any flaring after seating.

Crimping is not absolutely necessary in many cases, as seating the bullet will draw the flare back in. It depends on the gun and how tight the chamber is. My glock 17 never needed a crimp, but my Cz did. I do it anyways to ensure reliable feeding, but thats the only reason, at least for 9mm.

Have fun.
 
Yes the case mouth needs to be belled in order to accept the bullet with damaging the case or the bullet. As mentioned, the case mouth bell should be minimal.

No, crimping is not required after seating the bullet. The seating die will push the case mouth flush with the bullet. I have loaded hundreds of thousands of 9mm rounds without ever crimping a single one.
 
Belling - yes, just enough so that inserting the bullet doesn't crumple the case.

Crimp? Depends on what you think of as crimping. The normal kind of crimp you would put on a rifle or revolver round will mess up your rounds altogether; they will go too far into the chamber for the firing pin to strike the primer. The taper crimp Rugerman mentions is, in effect, just reducing the bell you put into the mouth. It's not something really perceptible, ie.

Dead horses are there to be flogged. Far better to ask a question somebody has already asked (OK, not one about bear defence) than make a silly mistake.
 
IMHO the Lyman 'M' die is the best product going for opening up pistol brass for bullet insertion. Instead of a 'bell', which allows misalignment, it creates a even 'step' for the bullet to enter the case evenly. As far as a crimp, the 9mm Luger round needs a firm crimp to prevent the bullet from telescoping back into the case and raising pressures to an unsafe level. The Lee carbide factory crimp die is your friend; not only does it provide a firm crimp but makes sure every round chambers in your handgun.
 
I have loaded 10s of 1000's of both 9mm and 45ACP and ran them all through the Lee Carbide Factory Crimp die as the last step. Never had a problem with feeding in multiple guns.

Flaring depends on the bullet you are using. I've found it changes with every different bullet style you are using, be it hard cast, swaged, coated/plated or jacketed. A little experimentation is the rule in reloading. Flare the minimum amount for the bullet you are using.

Be safe.
CS45
 
As far as crimping my advice has always been to crimp for the gun, not the bullet.

For imstance my 9mm gets a firm crimp, since my 1911 has a very steep feed ramp on the barrel and if I do not have a good firm crimp on the round I see a lot of bullet pushback into the case which can be a really bad thing as pressures build up quickly. My 4506 (45 ACP) only gets enough of a crimp to remove the bell since the pistol has a huge polished feed ramp and eats anything I feed it.

As a rule when setting up a new bullet in my 9mm I set a light crimp on a dummy bullet (no powder or primer). Measure the OAL and then load it into the pistol a couple of times. Re-measure the OAL. If it has setback more than I'm comfortable with, I will make up another dummy with a better crimp and try feeding again. That way I ensure I have the least amount of crimp required for the pistol.

My $0.02

Later.....
 
What can I say? I have never seen a manual nor a die instruction set not recommend a crimp on a semi-auto round. Taper crimp it should be, NOT a roll crimp, but a crimp in any case. A true taper crimp does return the case wall to the original taper, such as it fits in the pistol chamber properly, and headspaces on the edge of the case mouth.

Obviously, it has been the satisfactory experience of a couple here, that such ain't necessary. Could be. to the OP, I'll say if you are having feeding problems or ignition problems, one of the first suspects is your crimp - try to make it a perfect imitation of a quality factory round.
 
As far as crimping my advice has always been to crimp for the gun, not the bullet.

For imstance my 9mm gets a firm crimp, since my 1911 has a very steep feed ramp on the barrel and if I do not have a good firm crimp on the round I see a lot of bullet pushback into the case which can be a really bad thing as pressures build up quickly. My 4506 (45 ACP) only gets enough of a crimp to remove the bell since the pistol has a huge polished feed ramp and eats anything I feed it.

As a rule when setting up a new bullet in my 9mm I set a light crimp on a dummy bullet (no powder or primer). Measure the OAL and then load it into the pistol a couple of times. Re-measure the OAL. If it has setback more than I'm comfortable with, I will make up another dummy with a better crimp and try feeding again. That way I ensure I have the least amount of crimp required for the pistol.

My $0.02

Later.....
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This is a great idea. Thanks.
 
Shootshellz said:
As far as a crimp, the 9mm Luger round needs a firm crimp to prevent the bullet from telescoping back into the case and raising pressures to an unsafe level.
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I disagree. What prevents bullet setback is the fact that you pressed a bullet into a case that is smaller than the bullet's diameter. This is what creates case tension. Your case should be slightly hourglass shaped along its length, and where the bullet base ends should be pretty obvious by looking at a finished cartridge.

Lead doesn't rebound as much as brass when worked or swagged. Therefore when you attempt to over crimp by squeezing the brass against the lead inside, the brass will rebound a tiny bit but the lead will more or less stay squeezed down in size. This is the most common cause of dangerous bullet setback, because you have eliminated the tension that was present before crimping.

Crimping has nothing to do with holding your bullet when reloading 9mm or other pistol cartridges. The goal in crimping is just to remove the bit of bell that you made in order to accept the bullet. The best way of ensuring your crimp is ok is to actually measure the case diameter where the bullet sits, and ensure the very end of the case mouth is about the same. Always of course remove your barrel and test the fit of your finished rounds before committing to bulk production.
 
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Sorry, Skyhawk, but the good folks at Speer agree with yours truly (check your Speer reloading manual #13, page 500). Enough said.
 
My vote is for the Lee factory crimp as well. It basically returns the case to its original size, crimping the bullet in place. I haven't had a issue with it since Ive been reloading 9mm, and that is a lot of rounds for IPSC.
 
Shootshellz said:
Sorry, Skyhawk, but the good folks at Speer agree with yours truly (check your Speer reloading manual #13, page 500). Enough said.
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I only have 6 reloading manuals. Speer is not one of them. Speer is evil and I boycott them for making cases with already crappy (too fat) primer pockets :p Perhaps you should tell us what your Speer manual says and not keep the entire world of shooters in suspense, only to suffer a multitude of sleepless nights?

I'll go with my manuals, my own experience, my IPSC guru, and with Brian Enos and friends on this one instead. Crimping does NOT hold a 9mm bullet. You're thinking of revolver with a roll crimp (cannelure) thingy.

It is case tension that holds your bullet with pistol cases such as 9mm, and if you attempt to taper crimp to the extent that it malforms your bullet inside, you will lose that tension and expose yourself to possible injury due to bullet setback when chambering. This is REALLY basic stuff that newbies should learn before they even buy their first press.

Additionally, I'll add that these straight walled pistol cartridges seat in the chamber on their case mouths - that little ridge of case around the bullet is actually sitting against a ledge inside the chamber of your barrel. If you crimp too much, that edge will slip past that ledge and your case will end up being supported only by the extractor or by the bullet itself being stuck in the lands.

A 9mm crimp is not a "crimp", but simply removing the bell that you made in order to originally seat your bullet. That's all.
 
So the man doesn't trust Sierra - howzabout Hornady?

Certain straight-walled cartridges such as the .45 ACP, 9mm, 10mm and .30 carbine headspace on the cartridge mouth. If the case mouth is rolled into a cannelure, it will not headspace correctly in the chamber. This can lead to inaccuracy, malfunctioning and possible damage or injury. Hornady offers taper crimp dies for these cartridges. Instead of rolling the case mouth into a cannelure, the taper crimp die gently tapers the case mouth and reduces the diameter of the case mouth slightly. However, the case mouth will still headspace evenly and correctly.
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Over here we have the fly poop and over there the pepper....
 
The idea when re-sizing the case is to take down to s size slightly smaller that the bullet diameter. We bell the case slightly to facilitate starting the bullet cleanly then seat the bullet. The press-fit between the two component parts keeps creates the desired about of drag to keep them together during the feeding cycle. When we are crimping these loads, we are merely returning the belled portion of the brass to it's a appropriate dimension. You should NOT be crimping with enough force to deform the bullet. Doing so will affect accuracy and could affect hadspace/reliability.

Hope this helps

R
 
Skyhawk: "Speer is evil?". Got a good laugh out of that. And I can assure you that Enos has NEVER published a reloading book. And yes, I know the difference between a roll and taper crimp. Give it up, my friend... End of subject (I promise).
 
Shootshellz said:
I can assure you that Enos has NEVER published a reloading book.
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:eek:

Brain Enos has gone one step further and published a reloading video entitled "Competition Reloading with Brian Enos". This TWO HOUR video is 100% "how to", and he goes into great detail into what I (and others) have summarized in this thread, particularly with crimp beyond removing the bell and how a bullet can actually be made to loosen if the brass is pressed against it enough to malform, or at best lead to poor accuracy. He personally demonstrates two different methods of measuring the case mouth to ensure it does not come close to doing so when setting up the crimp die.

He also discusses at length how to select a resizing die that re-sizes the cases smaller than your bullet diameter (he provides minimum size differences) and that your finished round should be very slightly hour-glass shaped, and even shows a closeup of his finished rounds to illustrate this.

I highly recommend this video, especially because he talks about all kinds of little things that are just not covered in reloading manuals. If you're interested, it's the very first DVD listed on his store. (IPSC Shooting & Reloading DVDs)
 
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