Coke Bottle Good?

[XrayDoc88]

I came across a post from 2015 that mentions a "coke bottle" shape for brass.  Rather then reviving that old thread, I'll start anew.

 

I"ve been reloading 9mm brass on a Forster press using Redding dies.  The cartridges look nice and straight when I'm finished.  I just switched to a Dillon XL 750 with Dillon dies.  Some of my finished cartridges have a slight constriction immediately below the seated bullet, as if the sizing die is too agressive.

1. Is this the "coke bottle" shape that the old thread mentioned was good for preventing unwanted deeper seating of the bullet in the firearm?

2. The cartridges don't look like factory ammo with this shape.  Should I ignore this?

3. Wouldn't it be better to call this the "coke glass" shape, fat at the top and narrow at the bottom?

4. Or, do I need to get a different sizing die?

 

Thanks!

[AHI]

would have to see it but yes this is the coke bottle shape talked about.

[Postal Bob]

For 9mm reloads, that's normal. Usually referred to as the wasp shape. That's because technically a 9mm is not a straight wall case, but slightly tapered. But close enough that we can use carbide sizing dies.

 

 

[Matt1911]

I've had several "coke bottle" rounds in every batch I make. Never had an issue. 

[HesedTech]

Coke bottle good! ugh. 
 

Yes the coke bottle look is the result of the Dillon die slightly undersizing the brass. Prevents bullet setback. 
 

Edited April 26, 2020 by HesedTech

[muncie21]

I load with both Dillon and Lee dies. This shape/appearance is more prominent with Dillon dies.  In any event, it doesn't hurt anything.

[MemphisMechanic]

Click the arrow at the top right of that link.  

 

Edited April 26, 2020 by MemphisMechanic

[4n2t0]

Coke bottle = good.

[Fasthenk65]

1 hour ago, MemphisMechanic said:

Click the arrow at the top right of that link.  

 

 

tnx!

[XrayDoc88]

2 hours ago, MemphisMechanic said:

Click the arrow at the top right of that link.  

 

Thanks for the link to that thread and for Fasthenk65 originally asking the question.  I get so much smarter by using these forums!

[MemphisMechanic]

21 minutes ago, XrayDoc88 said:

Thanks for the link to that thread and for Fasthenk65 originally asking the question.  I get so much smarter by using these forums!

Just remember, you want your 9mm rounds curvy, just like your women.

 

.40 .45 and most other handgun calibers don’t show this because the walls are vertical, not tapered inward toward the top like a 9x19. In Luger this is a normal thing. If it passes a case gauge it’s good to go.

 

Edited April 26, 2020 by MemphisMechanic