Neck expander vs bushing for sizing?

[Ray B]

The sizing dies that I have are mostly the standard type where the die sizes the neck to smaller than spec then the expander button is pulled past the neck to size it to spec. The problem that I've read about and to some degree experienced is that the working of the brass causes it to harden and crack. Additionally, it tends to promote case stretching and encourage thinning of the brass near the web.

I'm wondering if these problems are avoided and a gain in case life is achieved by sizing with a bushing that reduces the neck to spec without as much working.

I can see that the bushing will be better from a theoretical explanation but I'm wondering in a practical sense if there is sufficient gain to justify purchase of bushing dies.

 

[nztimb]

Bushing is best as they are available in incremental sizes to get exactly the neck tension you want. I use them not only to reduce working the brass but alos to maintain the case concentricity at the neck/shoulder junction that aids accuracy. Anneal every 5th reloading cycle and brass lasts a very long time.

 

[bruce moulds]

bushing sizers can certainly reduce working of brass.
there is one caveat with them and it is that unless all case necks are the same thickness you will get variations in neck tension.
to solve this, either neckturn your brass or use an expander in conjunction with the bushing sizer.
bruce.

 

[Ray B]

unless all case necks are the same thickness you will get variations in neck tension.
bruce.

To avoid getting a lathe to turn the necks, since this is a small production situation (a few boxes of ammo per year) I am wondering if sorting the cases by neck thickness and then matching the thicknesses to a few bushings. In measuring the necks I find they vary from a thick of .0152" to a thin of .0135". The bullet is .308" which would indicate bushings of .335" to .338". should I expect reasonable results by sorting the cases into groups with necks .0135, .014, .0145, & .015" and using the bushing for that group?

 

[nztimb]

I tunred the necks for consistency but sorting the brass as you hsve noted is certinly a very practical solution. The bushes are cheap and as you are not volume loading would be the best way forward.

 

[bruce moulds]

if neck turning is a bore, just use an expander of appropriate size.
bruce.

 

[Ray B]

if neck turning is a bore, just use an expander of appropriate size.
bruce.

It isn't that neck turning is a bore - it's just that I am trying to avoid purchasing more equipment if it can be avoided since the amount of use wouldn't justify it.

I'm trying to avoid using an expander button as previously noted, using a bushing to resize the neck causes much less working of the brass.

 

[bruce moulds]

you use a bushing that only requires about 0.001" expansion on a correct expander to give good neck tension.
so you arte only sizing that much more than necessary, unlike the crappy sizing dies that factories make.
even if you expand 0.003" again, when you seat the bullet ,that is a total of 0.004", or 0.002" per side.
compared to 0.0015 per side without the expanding method.
1/2 of 1 thou will make no difference to case life, and avoid neck turning as well.
bruce.