new vs. fired cases

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varmint22man

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If you take a fired case and a new case and resize both of them , will they be the * exact same diameter ?
Thanks
 
Assuming you size them in the same die they should be so close as to not be able to measure the difference in diameter, assuming the fired case is not work hardened.

Something to consider:

New cases will be dead soft. Fired cases become increasingly harder (springy) as they are worked each time. After enough firings they can become work hardened enough that they will spring back and measure differently than a new soft case being sized. This is especially evident in how far the shoulder will be pushed back more so than diameter. It takes a very work hardened case that resists sizing to the point the diameter becomes a problem, although it can happen.
 
Now thats a poser, for sure thay'll be exact enough for reloading.

Here's another question, after seating the bullet will they both be the exact same diameter?
 
If you take a fired case and a new case and resize both of them , will they be the * exact same diameter ?
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Depends upon the chamber the fired case was fired in. Some people don't realize that you may need a small base die to get a fired case back to new factory brass dimensions right out of the box. If you fire your brass in a "generous" chamber, then many standard FL dies will not size the web portion of the brass enough to bring it back to factory spec's. This is a real PITA with machinegun fired brass, and a small base die is the only way to do it.

Don
 
This is a real PITA with machinegun fired brass, and a small base die is the only way to do it.
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I have yet to use a small base die reloading for my 1919. I don't even use U dies reloading for SMG's that really blow out the case. If the round fits a case gauge thats all you need.
 
???

Where? What diameter are you asking about? And why?

With more information we'd be able to answer you question more completely.
 
"resize both of them , will they be the * exact same diameter ?"

Nope.

And neither will once fired cases be the exact same sized diameter. Brass has a bit of difference in springback even in cases from the same lot and fired the same number of times. Reloading isn't a truely precise activity, no matter how hard we try to make it so.

It's not uncommon for virgin cases to be slightly under most die dimensions, just as it is with new factory ammo.
 
I have yet to use a small base die reloading for my 1919. I don't even use U dies reloading for SMG's that really blow out the case.
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Jmorris,

You're loading for a machinegun. I'm talking about taking machinegun fired brass with the web area of the brass blown out, and getting them to fit a tightly chambered boltgun.

Don
 
If you're trying to resize brass that is blown larger ie; machinegun brass, resize it with a full length resizing die and a hammer "nylon mallet" and no shell holder. Then use a punch to drive the case out of the sizing die. I've done this with 30/06 mil. brass that had been fired in a fully auto something that someone gave me. PITA yes, but it works, and it also was a PITA to swedge out the primer pocket.

If you use the shell holder it leaves some of the case still blown out at the end of the case.
 
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