I have about 1k lapua .308 brass for my Sako TRG.

Anyways i have shot it all once.  I processed a few hundred of them my normal way full length size with out the expander button, trimmed, ran it through a Sinclair neck expanding mandrel die.  I did this a year ago when i was processing a bunch of another batch of .308 for my Scar.

I was thinking about neck sizing the rest.  Would i still need to use my Sinclair neck expanding mandrel die to get proper neck tension?  All the brass has only been fired through my Sako.  What about chamfering? Like i said I haven't done it so i dont know if doing neck sizing rather than full length makes any other steps not needed.

Im not really sure if i should just full length size all of it this time and then neck size it next time, or start the process on what i haven't processed yet.

There are bushing dies that will just neck size or Fl size.  Then there is the Lee collet neck size die.   Some use a Redding body die (fl size) with the Lee collet die.

I use the Redding Type S Fl bushing die in 243 win..  This die gives you the choice to use the expand or not.  Most times more than 1 bushing is needed. I have 3.   Works well for me.

To answer your direct question, if you run them through a neck sizer (sans expander), you would still need to expand them with a mandrel.

That said, I'd recommend setting up your existing FL die to only bump shoulders .002-.003 back from their fired size. You get the chambering benefits of FL sizing, and are hardly working the brass (i.e. the benefits of neck sizing).

The only way you can get around not using an expander is if you have a custom ground die, or if you're using bushing dies.

Ive got a lee collet sizer that ive had unopened for years.

The collet sizer wouldn't need to be expanded afterwards; it's got a mandrel inside there to set neck tension.

That said, if it were me I'd still prefer bumping shoulders with an expanderless FL die.

Edit: But if you've got a ton of brass, I could understand the appeal of neck sizing it, and not having to lube it.

If any of this brass is going to be shot in the SCAR, you may be forced to FL size it. The case body area on the TRG is probably tighter, but you'd need to check the shoulder on fired cases from the TRG and SCAR to determine if you absolutely must bump them.

I keep the scar and trg brass seperate but will often process them one after the other since things are set up for .308.  I will only be FL sizing the scar brass.

On my precision stuff I separate each operation down so I can better control the results...

So these are the dies I use in order left to right..
Attached File


1)universal de-cap die
2) Redding comp shoulder die
3) Redding comp neck bushing die
4)Sinclair mandrel die
5) forester comp seater die

OP, depending on how sized they have been you may need to trim the brass after sizing, you may need to anneal the brass before/after sizing..lots of ifs...

I've always had and still do have great results using regular neck only sizing dies. I have some Redding and some RCBS. Set up is straight forward just like a full length die except it isn't necessary to cam over.

You can back them off if you wish to size less of the neck as well. They use the same expander as the full length die set.

There are of course many other types of dies for neck only sizing. The ones I mentioned are the most basic and easiest to use.

Using these dies and periodical annealing I have had brass life extend towards 20 cycles all while maintaining sub MOA accuracy in heavy barreled bolt action rifles.

Motor

If you're using a bushing neck sizing die you do not need to use another expanding die.

You set the neck tension with a bushing die by choosing the correct size bushing.

So you do bullet diameter + (2 x brass thickness). Subtract whatever neck tension you want and that's your bushing size.

So take 0.015" brass wall thickness. You take 0.308" + 0.030" = 0.338" - 0.002" neck tension = 0.336" bushing to set the proper neck tension.