choosing dies and bushings for PTG .308 Win Tac Match Chamber

[treetux]

Question... If I buy a full length sizing die with bushings for neck sizing... will that be all I need for reloading dies? If I understand right, with the correct neck bushing installed and the die "all the way down" this will full length size my brass and knock the shoulder back. If I remove the neck die, then it will act like a body die. By lifting the die up with the proper bushing installed then it will act like a neck die. Am I thinking about this correctly? Then if Redding cuts all their dies to minimum SAAMI specs and my new reamer is minimum SAAMI specs, is their a necessity for ordering custom dies? If I am approaching this correctly all I will need is a full length sizing/bushing dies a couple of bushing inserts and a Redding competition seating die and I should be set. My reamer has a .343 neck and with Lapua brass and 175 gr Sierra Match king bullets the outside measurement of the neck is .338 so how do I sellect the bushing size/sizes. I know this topic has probably been talked into the ground so help finding the information would be appreciated.

 

[RonAKA]

This may depend on the die. I don't believe the Forster Bump/Bushing die actually sizes the body. It only bumps the shoulder back, and sizes the neck as determined by the bushing you choose. Not sure about Redding.

On choosing bushing size, the chamber or fired case size is not of concern. If your loaded neck OD is 0.338, normal practice for bench shooting is to have the brass OD 0.001" smaller before bullet seating, or 0.337. To get it to that size you normally pick a bushing diameter 0.001" smaller than that to compensate for spring back after sizing. So in your case a 0.336 bushing should be about right.

 

[dreever]

If you are going to load for a magazine .003 smaller bushing would be better since light neck tension could allow the remaining bullets in the magazine to move out during recoil.
I load all my .308's this way using a .335 bushing for my no turn Lapua brass.
I prefer the Redding Competition die set with a micrometer seater and neck die and a body die to bump the shoulder.

Danny

 

[Laurie]

By lifting the die up with the proper bushing installed then it will act like a neck die. Am I thinking about this correctly?

treetux,

you're correct on your first two die-setting assumptions, but your third (above) may or may not work out. It usually does, but depends on how much the die sizes the body diameter down, that of course depending on both die and rifle chamber (hence fired case) dimensions.

If the die only kisses the case body, you're OK. If it reduces it substantially, the case lengthens since the displaced brass has to go somewhere. This moves the shoulder forward in relation to the case-head and bolt-face reducing headspace clearance, and will give hard chambering, or in extreme cases stop you chambering the round. When the die is screwed down fully, it pushes the shoulder back to the 'proper position'. So, you have to try this method out first and ensure cases still chamber easily. If so, you can use the die as a neck-die, or in practice a partial full-length sizer + neck-die.

In a tactical rifle or one used for any other type of shooting that needs easy chambering and bolt closure, the usual advice is to full-length resize, but if loads and pressures are moderate, neck sizing is fine. The Forster Bushing-Bump sizer is a really good model in such applications as it's a neck-sizer that also allows you to set the shoulder back - or not in which case, it becomes a neck only die.

In this, as with any die that moves the shoulder, you should adjust the setting in the press or use a non-standard thickness Redding 'Competition' shellholder so that the shoulder is only moved back a thou' or two from the fully fireformed position giving easy bolt-closure, but without creating the excess headspace that often results from using the die adjusted to the 'default position' hard against a standard shellholder.

Laurie,
York, England

 

[RonAKA]

If you are going to load for a magazine .003 smaller bushing would be better since light neck tension could allow the remaining bullets in the magazine to move out during recoil.

I agree 100%. If the round is going to sit in a magazine or be used for hunting you want more neck tension. Better to use the loaded round od minus 0.003" to get your bushing size. Also consider that your brass may thin over time and you may need to check this and go to a tighter bushing to compensate.