sizing once fired brass with bushings

[GSPV]

OK. Thanks! That makes sense. I thought it was 1 thou *larger* than a *fired* case. Whew.

That's why I always try to ask.

 

[timeout]

Not saying my way is the correct - or only way - but, I prefer to measure neck thickness and take that dimension times two, add bullet diameter, and subtract .003" to determine bushing size.

Which, if you accurately measure both the neck thickness and the bullet diameter, gives you the same thing as a loaded round minus 3 thou.

We all tend to say "3 thou neck tension", but that's just a stand in for it. The real neck tension is that minus the springback. As we all know, springback changes as the neck work hardens. Till it is annealed, that is. Provided that it is correctly annealed

I am figuring for the springback, not saying 3 thou tension, and I anneal every firing. May not be the proper way, but it's my way. ;D

 

[Fellas]

very good input thanks
guys

 

[steve-o]

check outer diameter and thickness of neck then .308 see what the difference is after you have full length resized. it's the inner diameter that tells you how much neck tension you have, not outer. if you have military brass they are a bit thick and would give you more neck tension if you don't have the expander in the fl die.
so .308 bullet the mouth of the brass id should read .305 if you want .003 tension. if it is military brass, recheck OD, you may have to trim. (and probably should based on measured thickness run out).

 

[CatShooter]

if it is military brass, recheck OD, you may have to trim. (and probably should based on measured thickness run out).

What does checking the OD (Outside diameter) have to do with trimming???

 

[steve-o]

Well Catshooter, military chambers are a little loose and the brass is for 7.62 nato are thicker due to the pressures they run at. After FL resizing some military brass on standard rcbs or hornady dies will not chamber in a bolt action rifle with a standard saami chamber or will be really tight because the OD is greater than saami spec for the neck due to the thickness. 7.62 brass is definitely different than .308 brass, thicker, heavier and holds less volume. The nice thing about some military brass is it has been annealed.
This is just for military brass like lake city that was fired in a full or semi auto military rifle.
That's been my experience with it, after fl resize it may read .346 or so on a loaded round, that don't fit in a saami chamber.

 

[CatShooter]

Well Catshooter, military chambers are a little loose and the brass is for 7.62 nato are thicker due to the pressures they run at. After FL resizing some military brass on standard rcbs or hornady dies will not chamber in a bolt action rifle with a standard saami chamber or will be really tight because the OD is greater than saami spec for the neck due to the thickness. 7.62 brass is definitely different than .308 brass, thicker, heavier and holds less volume. The nice thing about some military brass is it has been annealed.
This is just for military brass like lake city that was fired in a full or semi auto military rifle.
That's been my experience with it, after fl resize it may read .346 or so on a loaded round, that don't fit in a saami chamber.

I load 308 commercially, and use tons (literally) of LC brass. I have not found the brass to be thicker (the weight is in the range of commercial brass), or more difficult to size... or any of the other complaints about it. It is very good brass.