Brass shrinkage?

[craigyboy]

Up at the loading table last night, noticed again that for some reason my brass is shrinking, I trimmed my brass when I first got it to 1.743, after the second firing its down to 1.741 and in some cases 1.738 came up, what the hell is that all about? I thought it might have been the neck die as I dont lube but do use redding ti- nitrade bushings, but I checked a few before and after sizing and if anything they were coming out of the wilson neck sizer longer by 1-2 thou, anyone shed some light on this one? Cases are supposed to stretch after firing not shrink

[Alycidon]

Some of my Lapua PPC cases did that but they still shot OK.

 

A

[silentsoulsleave308holes]

can be two things

 

1) was it warm when you measured first? brass may have got warm from working it or just holding in your hands whilst cutting then when cooled just shrunk back

 

2) when you fire it, the brass expands to the chamber and will never spring back 100% so because the brass has changed it shape width ways it will shorten length ways for a firing or two before it starts to the grow forward

 

say you neck sized for a few shots to expand the brass and trimmed, the case grows closer to the chamber size.

 

when it has done this the only place the brass can grow is then forward

 

 

 

the saying freeze the balls of a brass monkey comes from old wooden "pirate oooaarrrr me ansum" type ships where the cannon balls were stacked in a brass triangle stacked vertically.

 

the brass triangles (monkey) were made slightly tight so the balls could be stacked upright

 

on very very cold nights the balls would cool right down reducing in size an drop out of the monkey hense the saying

 

or some that which promotes growth and vigour like that

 

 

ja

[Guest varmartin]

craigyboy...I gave it some thought but Silentsoles got me thinking lateraly....so I posted a new topic.

 

Martin