[Wazz13]

The other day I was getting ready to build a new load for my Remington 700 in .223. I recently picked up some federal brass, and decided to give it a try. FL Sized, polished, trimed to 1.755", primed w/WSR, 23.0 g of Hodgdon 335, COL of 2.300".

I put 2 of these rounds together and steped out my back door to shoot them. Both loaded fine, no signs of pressure, but when I checked case length they had shrunk to 1.750. Is that normal? I have always re-loaded military brass, Lake City, and never had them shrink after being shot.

What are your guys thoughts?

Thanks

 

[Marshal Kane]

My thoughts are you should recheck case length again after FL resizing or was this the way you did it? If a case expands after firing and doesn't quite return to the FL sized dimensions, would expect a bit of shrinkage. Sizing should restore the case length back to the trimmed length and possibly a bit more.

 

[broom_jm]

Yup, what Marshal said....it isn't firing, so much as resizing, that causes case lengths to grow. I seem to remember Uncle Nick wrote a long post concerning the whys n' wherefores.

 

[fguffey]

wazz13, again I form cases, there are some cases that shorten .035 thousands from start to finish, this is the reason I have trouble taking some of the advice seriously on forms. It is said cases blow out, there thinking OUT means in the direction of the exiting bullet, my experience has shown when the case expands and fills the chamber the case blows out against the chamber wall and at the same time pulls the neck back when the case stretches OUT, and when sizing my cases the neck gets longer, when the ram is lowered and the sizer ball is pulled through the neck the neck expands, when the neck expands the neck shortens, the neck does not get thicker or thinner.

And the worst answer I have read, "the case is not fully grown until it is fired 5 times, at that time the case should be full length sized". If you fire the case in a chamber the neck expands, expanding the neck when firing and or sizing shortens the neck, but when I am sizing and forming cases I measure first, size and measure again then fire and measure again. MY 30 Gibbs, 338/06 and 35 Whelen start with 30/06 cases that are 2.496 long after necking the cases up all are as short as .2465, after fire forming the 30 Gibbs the case fill the chamber and form to the shoulder, it is not unusual for the cases to shorten an additional .010 thousands, after the cases are formed THEN I can expect the case to stretch?? or is that FLOW?

So if your cases shortened when fired it could be caused by the case filling the chamber, when the case stretches the brass must come from somewhere. the neck can pull back and shorten because of neck stretch.

F. Guffey

 

[fguffey]

Forgive, that is normal for me, my thoughts,

F. Guffey