9mm case mouth to big with bullet

Did you use a taper crimp die and do a crimp to remove the flare for the bullet?

I don't load 9mm, but I will ask if you removed the flare with your taper crimp die.

chris

None the semi-auto handloads I make get crimp, I just use a taper crimp die to "deflare" and check with the plunk test...

Nicksterish said:

I am having problems with my 9mm. I have a L.E. Wilson case gauge...

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Sorry to hear that.

Nicksterish said:

...resized the brass and seated a primer the brass fits in the gauge flush with the gauge.

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Resizing takes the case to a much smaller size, so that the Expander can do its job. So, of course the smaller than standard case fits your gauge very nicely.

Nicksterish said:

When I flared out the case and charged the case (horandy powder measure on my progressive press.) And placed a bullet and seated the bullet checked it with L.E Wilson case gauge and is sticking up.

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The flare has to be eliminated with a process called a "Taper Crimp", which oddly enough is neither a "taper" or a "crimp". This process has to be applied before the cartridge can be tried again in the Case Gauge. This is because the taper crimp is used to eliminate all the flare that was installed for bullet seating.

Nicksterish said:

Ended up using my micrometer and the case mouth was measuring. .358. The ones that passed were measuring. 356. (I'm Using 95 grain plinking bullets. .355 dia)

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I think you got that wrong some how. As the diagram in your reloading manual shows, the correct dimension at the case mouth needs to be just under 0.380". Since the 9mm bullet itself is 0.355", I highly doubt that you measured 0.356". However, I could believe 0.376". Please go back and measure that again.

When the Taper Crimp takes the case mouth much smaller than 0.376", the remainder of the case wall can buckle and bulge outward. That will keep the cartridge from fitting your gauge. The Taper Crimp setting is one of the harder adjustments to set and may take you 30 minutes. Luckily, once it's set it only needs to be checked once a year. Set it during a production run to give you a final case mouth diameter between 0.376 and 0.378". At that point, all the other issues should disappear.

Taper Crimp is ONLY measured at the case mouth on the last 0.040" of the case, as shown below...


Hope this helps.

What does the bullet measure?

The big problem comes from if you set the taper crimp die on a long case. Because then when you get a short case it doesn't reach up into the die far enough to take all the flare out of the case. Then you drop it into the Wilson gauge and it fails.

Screw you taper crimp die in another 1/4 of a turn and try the same case again in the same gauge. You'll see it drops right in and right back out. If it doesn't , screw in another 1/4 of a turn.

If you don't set your taper crimp die up on the shortest case you can find so it will pass the gauge, you will always have some that won't pass.
Yes, the longest ones may be over crimped a little but unless you sort your 9mm s to length, which no one does, you won't be able to get away from this problem unless you set the taper crimp die up on the shortest case.

Screw your taper crimp die in another 1/4 of a turn.

If it’s just a plinking bullet it’s got to be the bullet, unless it’s federal brass- a little thicker.

JPIMBO said:

If it’s just a plinking bullet it’s got to be the bullet, unless it’s federal brass- a little thicker.

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• Since the Sizing Die controls the outside dimensions on every piece of brass regardless of manufacture, I highly doubt it's the brass.

• The LE Wilson gauge closely mimics the chamber by being built to SAAMI specs. But not many chambers absolutely adhere to SAAMI specs. So you'll need to stop using the gauge and start comparing your reloaded cartridge to the gun's chamber. Since you are never going to fire a single round in the gauge, the chamber has the ultimate say. It's the chamber your ammo has to make happy.

• Since every chamber is different, that means some guns have more trouble. Since every bullet is different, that means some bullets make more trouble. To go any further we're going to need more details on the gun, the bullet, and probably the brand and age of the dies.

Hope this helps.

tightgroup tiger said:

The big problem comes from if you set the taper crimp die on a long case. Because then when you get a short case it doesn't reach up into the die far enough to take all the flare out of the case. Then you drop it into the Wilson gauge and it fails.

Screw you taper crimp die in another 1/4 of a turn and try the same case again in the same gauge. You'll see it drops right in and right back out. If it doesn't , screw in another 1/4 of a turn.

If you don't set your taper crimp die up on the shortest case you can find so it will pass the gauge, you will always have some that won't pass.
Yes, the longest ones may be over crimped a little but unless you sort your 9mm s to length, which no one does, you won't be able to get away from this problem unless you set the taper crimp die up on the shortest case.

Click to expand...

I get a little nervous doing this with a Lee “seat and crimp” die. The instructions say that if it’s screwed in far, then at some point it will put a roll crimp on the case. I haven’t experimented with it to find out how far I can go.