Case shrinkage after fireforming. How short is too short?

[Despotes]

I fireformed some 338 Lapua ammo today in my 338 Lapua Improved (Langley) and noticed the cases had shrunk in length.
Unfired 338 Lapua case length @ 2.716" shrank down to an average of 2.688" after fireforming.
How much shrinkage is acceptable? No Constanza jokes. lol
Here's the reamer print if it helps

 

[Despotes]

Also, can I use a regular 338 Lapua headspace gage for my fireformed rounds?
Ex; L.E. Wilson Case Length Headspace Gage 338 Lapua Mag

 

[PackersFanboy]

tried cambering fire formed brass with new rounds. I would be wondering where that brass was pushed into thicker neck or shoulders.

 

[ShtrRdy]

I don't know if there's an absolute answer, but it seems to me that shorter is probably okay as long as there's enough to hold the bullet. If it were too long then that creates serious problems.

 

[MagnumManiac]

ALL cases shrink in length when fireformed in a larger chamber, the brass has to come from somewhere, and this somewhere is the neck and shoulder.
It will generally grow some the next time you size it, a few firings and it will be back to normal length.
My brass generally shortens, .020"-.040", depending on how much it is blown out from the parent case.
It poses no problem to function.

Cheers.
gun)

 

[RockyMtnMT]

ALL cases shrink in length when fireformed in a larger chamber, the brass has to come from somewhere, and this somewhere is the neck and shoulder.
It will generally grow some the next time you size it, a few firings and it will be back to normal length.
My brass generally shortens, .020"-.040", depending on how much it is blown out from the parent case.
It poses no problem to function.

Cheers.
gun)

Yep! For me and my Lapua based cartridges I generally never have to trim case length. They never get back to spec. The only trimming I have done is to uniform them all to the same length after fire forming.

Steve

 

[Despotes]

OK good. Thanks for the help guys.

 

[Despotes]

Another question. I should be able to use the Hornady Lock N Load modified 338 Lapua case (w/Hornady Lock N Load Overall Length Gauge) since they both use, according to the reamer specs, the same 338 Lapua Go-.004 gauge. I'm assuming both versions, Langley and Lapua, headspace off the same datum line on the shoulder.