Well, I'm an old TC shooter, so I've got to add my $.02. I've had a lot of them (mostly in rimmed calibers) that were excessive on the headspace, that or I had brass that had thinner rims than they should have. Anyways I used to get a lot of backed out primers on the first firing of a virgin case. However, where I have to disagree with a few on this thread is on the practice of neck sizing brass in a single shot "topper" style rifle. This might work for one or two firings, but once the case fills out a little you won't get the action to close. Here's what I would do... Partial full length sizing, and there's a couple of approached here.
1) The Hilbilly Method. Back out the sizing die 1/2 turn, size the case (preferably with the expander plug out) and then see if action locks up smoothly without undue effort. If it doesn't, turn the die in another 1/16th turn and repeat the process. Keep this up until you win. The problem with this method is that its very hard to control EXACTLY how much headspace you have, which brings us to method #2.
2) The "I Spend Way Too Much Time and Money Reloading" Method. First, you aquire a headspace gauge (like the RCBS precision headspace mic) and measure a fired case to determine how much its growing. Then you screw your die in fulsh to the top of the shellholder. Then you select the correct Redding Competition shellholder that will bump the shoulder back .002" to .003" These come in a box that gives you headspace anywhere from .002" to .010" long depending on which one you use. Still, start with at least the next shellholder bigger (if your math says to use the +.006" shellholder, use the +.008" one first.)
On a side note. I've always loaded better ammo with less total indicated runout with that method than I have just neck sizing. It stands to reason that you will achieve less runout sizing the upper part of the case and the neck at the same time in the same die that you will just sizing the neck. Also, those Redding Competition Shellholders are a good investment, being that most of us avid riflemen have lots more than one caliber with the same head diameter. I mean I've got 11 different calibers that I load with .473" head diameter.
1) The Hilbilly Method. Back out the sizing die 1/2 turn, size the case (preferably with the expander plug out) and then see if action locks up smoothly without undue effort. If it doesn't, turn the die in another 1/16th turn and repeat the process. Keep this up until you win. The problem with this method is that its very hard to control EXACTLY how much headspace you have, which brings us to method #2.
2) The "I Spend Way Too Much Time and Money Reloading" Method. First, you aquire a headspace gauge (like the RCBS precision headspace mic) and measure a fired case to determine how much its growing. Then you screw your die in fulsh to the top of the shellholder. Then you select the correct Redding Competition shellholder that will bump the shoulder back .002" to .003" These come in a box that gives you headspace anywhere from .002" to .010" long depending on which one you use. Still, start with at least the next shellholder bigger (if your math says to use the +.006" shellholder, use the +.008" one first.)
On a side note. I've always loaded better ammo with less total indicated runout with that method than I have just neck sizing. It stands to reason that you will achieve less runout sizing the upper part of the case and the neck at the same time in the same die that you will just sizing the neck. Also, those Redding Competition Shellholders are a good investment, being that most of us avid riflemen have lots more than one caliber with the same head diameter. I mean I've got 11 different calibers that I load with .473" head diameter.
