How much shoulder becomes neck when making 30br brass?

[P1ZombieKiller]

Ever wondered how much of the shoulder actually becomes part of the neck when you are necking up brass. I decided to document this in easy to see photos (is this a "photo-definition")
Below you will see 1 unaltered Lapua 6br case. Then I turned the neck to .009" so you can easily see the difference between the shoulder and the neck. I tried to turn it right down to the junction of the case when the shoulder begins. Then I necked up the case and now you can easily see that it's alot.

This also answers the question "turn then expand" or "expand and then turn"?

 

[Terry]

Interesting!

I would have been wrong.

 

[tonyb]

Very good info, thanks for taking the time to explain that!

Tony.

 

[Eddie Harren]

P1ZK, now include a photo of a fire formed case. Thanks.

 

[mikecr]

Is this now your false shoulder?
Seems like the reamer print would show this.

 

[Eddie Harren]

"Is this your false shoulder?" There is no need for a false shoulder when fire forming necked up 30BR brass.

 

[Judd]

Thanks, that is interesting. I would've been wrong on my suspecisions also.

 

[P1ZombieKiller]

P1ZK, now include a photo of a fire formed case. Thanks.

I only would have a pic of a case that has been turned first, and then fire formed. I don't have a pic of a case that was only fire formed and not turned.

 

[Shynloco]

P1ZK, now include a photo of a fire formed case. Thanks.

I only would have a pic of a case that has been turned first, and then fire formed. I don't have a pic of a case that was only fire formed and not turned.

QUESTION: After fireforming, will that piece of brass also need to be trimmed or did it need trimming when the case was necked up (before fireforming) to it's last pictured state? Just curious. Thx

 

[P1ZombieKiller]

The case as pictured in the last picture, when loaded with a bullet (assuming the bullet will load deep enough into the case to interact with the non turned portion of the newly formed neck), would not chamber in my chamber to be fire formed as this would be thicker than the .330 chamber my gun has.

 

[Shynloco]

Sorry...I meant in length/case length, not brass thickness as that would depend on the reamer profile to allow for chambering.

 

[Judd]

Sorry...I meant in length/case length, not brass thickness as that would depend on the reamer profile to allow for chambering.

Always trim to length prior to turning necks or your depth on the neck turning pilot will be different for every case.

To make 30BR brass, I normally expand then trim then turn the necks. Zombie used this to prove the point that you expand then turn the necks and not turn the neck first or it will look like this one and still need turned again due to the shoulder becoming part of the neck.

 

[pikespeakgoat]

As they say, a picture is worth a thousand words, thanks.

 

[M-61]

As they say, a picture is worth a thousand words, thanks.

+1.....I would have lost if I bet on the results