"coke bottle" shape when reloading 9mm: good, bad, ugly?

[ddc]

I've seen more than a couple of times a poster complaining about the "coke bottle" shape of his 9mm reloads and wondering what they can do to avoid what they perceive as a problem.

I'm of the mind that the "coke bottle" shape is not a bad thing but is actually something positive as it would seemingly, to my mind, act against bullet setback.

I'm used to seeing it on my reloads; it doesn't bother me a bit.

I'm curious what you guys think about the "coke bottle".

Thanks!

 

[Mk-211]

It's nothing to worry about.

You can try adjusting your die to not bell the case as much. That and check the sizing die to see how much of the case is getting done/resized.

 

[9mmepiphany]

good, bad, ugly?

Definitely Ugly

...wondering what they can do to avoid what they perceive as a problem.

My understanding is that it is a am artifact of the ring in most carbide resizing dies combined with deep seating long (147gr) bullets

I had a friend who was really bothered by the budge. He ended up getting a Sizing die from Mighty Armory and it did away with the budge

 

[AJC1]

It's taking a tapered case, making it a straight wall and cramming a bullet in. If you hate the look use steel dies.

 

[CoalCrackerAl]

Hmmm... never came across that when loading 9mm. Have a pic of it?

 

[Shak3s1977]

Hmmm... never came across that when loading 9mm. Have a pic of it?

Seems Dillon dies make it more pronounced then other dies. It doesn't bother me though and I figure it helps a little more with bullet setback.

 

[CoalCrackerAl]

Interesting thanks.

 

[Walkalong]

Ugly yes. Functional yes.

Steel dies are tapered like the case, so that's one way to get rid of it. My old Lee 9MM sizer has a long tapered carbide ring in it, and it doesn't do it, I don't know about the newer ones. I have no experience with the Mighty Armory 9MM sizer mentioned, but it is supposed to eliminate it as well. My standard Redding sizer does it, but they shoot just as well.

 

[Chuck R.]

I like the Dillon add, and I get the "wasp waist" when loading either 147s or sometimes 135s in my 9mm using Dillon dies

Hasn't hurt anything to date over 10's of 1000s of rds.

 

[ddc]

Ugly yes. Functional yes.

Steel dies are tapered like the case, so that's one way to get rid of it. My old Lee 9MM sizer has a long tapered carbide ring in it, and it doesn't do it, I don't know about the newer ones. I have no experience with the Mighty Armory 9MM sizer mentioned, but it is supposed to eliminate it as well. My standard Redding sizer does it, but they shoot just as well.

I've only used Lee dies. What is it about steel dies that makes them different from carbide dies as far as affecting the shape of the sized case?

 

[9mmepiphany]

What is it about steel dies that makes them different from carbide dies as far as affecting the shape of the sized case?

Carbide dies are over resizing your 9mm cases. The carbide ring in the dies are trying to turn your tapered case into a a straight walled case.

Steel dies don't have that ring and the inside of the die is tapered to match the taper of the 9mm case...so it is resizing to the designed taper of the case

 

[243winxb]

I'm of the mind that the "coke bottle" shape is not a bad thing but is actually something positive as it would seemingly, to my mind, act against bullet setback.

If it works, it works.

1.The loaded rounds must chamber fully. Bullet diameters larger then .356" , may be a problem in tight, short chambers.
2. Is the case sizing the lead bullet smaller in diameter?
3. Longer , heavier bullets will seat deeper into the case. More bulge?
4. Brass can be very different in wall thickness, construction. Pick a brand that works well. Some have a step inside.
5.RCBS does have a carbide tapered insert, for correct sizing.

 

[tightgroup tiger]

My RCBS has a tapered carbide insert in it. I have been all over my cases with my dial indicators and the cases have a true taper on them when they come out of that resizing die.
I can still see the base of the bullet but they don't have the wasp waist look to them. I get 60lbs of neck tension with those dies on my strain gauge also.

 

[Walkalong]

I've only used Lee dies. What is it about steel dies that makes them different from carbide dies as far as affecting the shape of the sized case?

Steel dies are tapered like the case, so that's one way to get rid of it.

My RCBS has a tapered carbide insert in it. I have been all over my cases with my dial indicators and the cases have a true taper on them when they come out of that resizing die.
I can still see the base of the bullet but they don't have the wasp waist look to them. I get 60lbs of neck tension with those dies on my strain gauge also.

5.RCBS does have a carbide tapered insert, for correct sizing.

Nice.

 

[FROGO207]

It has not bothered my ability to use my finished ammo so it is just an artifact of the reloading process to me. It is more pronounced with lead bullets because of their slightly larger size. It is also more moticable on 30 Carbine as well.

 

[ddc]

Carbide dies are over resizing your 9mm cases. The carbide ring in the dies are trying to turn your tapered case into a a straight walled case.

Steel dies don't have that ring and the inside of the die is tapered to match the taper of the 9mm case...so it is resizing to the designed taper of the case

So why couldn't a carbide die be made in a similar fashion? i.e. "tapered to match the taper of the 9mm case...so it is resizing to the designed taper of the case" ??

 

[drband]

So why couldn't a carbide die be made in a similar fashion? i.e. "tapered to match the taper of the 9mm case...so it is resizing to the designed taper of the case" ??

see this quote:

My RCBS has a tapered carbide insert in it. I have been all over my cases with my dial indicators and the cases have a true taper on them when they come out of that resizing die.
I can still see the base of the bullet but they don't have the wasp waist look to them. I get 60lbs of neck tension with those dies on my strain gauge also.

You can buy one on the RCBS website for $47.95 with free shipping.

 

[sparkyv]

"coke bottle" shape when reloading 9mm: good, bad, ugly?

Honey, do my reloads make me look fat?

 

[Nature Boy]

I use the Dillon 9mm carbide dies. They pass the case gauge, plunk test and feed reliably in 6 different guns.

In the list of things to worry about this wouldn’t even make my top 50

 

[jmorris]

I set my size dies so the case drops back into the case gauge. A tapered case won’t be undersized this way, that only happens if you screw the die down until it bottoms out.

Not like screwing it down and swaging the brass too small in the body fixes any imperfections below the mouth of the die anyway. Have to use a roll sizer for that.



Once they are boxed it takes 10 seconds to go row by row and ensure sufficient neck tension.



and your loaded ammunition doesn’t looks factory vs goofy.

 

[tightgroup tiger]

I set my size dies so the case drops back into the case gauge. A tapered case won’t be undersized this way, that only happens if you screw the die down until it bottoms out.

When I first got my set of RCBS carbide 9mm dies I would get a case jammed in the barrel hard enough I had to use a hammer and brass punch to get it dislodged, every 300-400 rounds. In looking for the cause of this I checked the gap between the shell plate and the bottom of the resizing die with a case in the die and saw I had about a gap. It was bulged cases that weren't getting pushed back far enough.

I brought the die down until it was touching the shell plate while under load and I haven't had that problem since. Probably 30k rounds later and not a problem with resizing bulged cases with this die. They all pass my Lyman case gauge and haven't jammed in my barrel since.
I get one with a rim dinged up now and then but that's a different problem.
As I said earlier, I can shine light off of a round and see where the base of the bullet is but other than that they don't have wasp waist at all.

I have to bottom mine out, Like most of us, I don't have a roller set to straighten case bulges back out. Your ammo probably looks like factory ammo when loaded with your procedure.

 

[GeoDudeFlorida]

"coke bottle" shape when reloading 9mm: good, bad, ugly?

Honey, do my reloads make me look fat?


View attachment 1106259

“No, it’s the fat that makes you look fat”. And that’s when the fight started.

 

[CQB45ACP]

I use the Dillon 9mm carbide dies. They pass the case gauge, plunk test and feed reliably in 6 different guns.

In the list of things to worry about this wouldn’t even make my top 50

You worry about 50+ things?

For 9mm I use a Lee carbide die set and mine don’t look this way.

 

[9mmepiphany]

So why couldn't a carbide die be made in a similar fashion? i.e. "tapered to match the taper of the 9mm case...so it is resizing to the designed taper of the case" ??

You answered your own question in Post #10

I've only used Lee dies.

They can, Lee chooses not to

 

[drband]

You answered your own question in Post #10


They can, Lee chooses not to

Yes, and RCBS charges $48 for just the sizing die, almost 2x what the Lee sizing die costs separately.