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With .308 in my M14 I neck sized 6 or 7 times before I do a full length resize. I had a batch of hand-loads that on the 9th necksize gave me chambering issues. There was nothing visibly wrong with the rounds in terms of length or anything else that I could see, but the bolt wouldn't close. A full length resize fixed it.

Alpha1 wrote:

Just wondered if there was a number or some thing people used before full length sizing.

Like you, Alpha1, most people do not bother to count or lose count over time. All I can tell you that, to satisfy my couriosity, I carefully logged each reload and I managed 37 in 7.62X54R before the first neck split. I then anealed that batch and I am up to further 5 reloads and still counting. Load is exclusively cast bullets with moderate pressure to get me comfortably to 300yds. I do not use collet neck sizer (Lee) because it is designed for jacketed bullets and works the brass more than is needed. Instead, I have a die made by CH4D, which uses bushes made to special order. Basically, I measure the necks of loaded rounds and get a bush .002" smaller. When the cases begin to stick it is time to "partially full length resize", which I do by setting the F/L sizing die to bottom out on the case holder and then back off one full turn. With 303 it is case heads that separate before the necks split.

Alex

Full-length size everything - if you want accuracy and a gun that cycles easily. Why wouldn't you?

Fire-formed brass can improve accuracy.

The Gun Pimp wrote:Full-length size everything - if you want accuracy and a gun that cycles easily. Why wouldn't you?

What halodin said. The brass is perfectly sized to your chamber.

HALODIN wrote: Fire-formed brass can improve accuracy.

Are you sure? Any idea how it does that?

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Yes, although I haven't seen improvement in brass from all manufacturers. I haven't seen any improvement in Lapua, but I most definitely have seen an improvement with Federal. Why do you doubt it?

HALODIN wrote:Why do you doubt it?

Just have never heard a convincing argument or experience; one that is statistically significant & not based on marketing stories or rumour etc.

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I was surprised when I didn't see any benefit with the Lapua brass, I assumed it was an acknowledged fact and it applied across the board. I didn't test it far enough to see after X number of shots whether the Lapua brass would eventually benefit. There was no discernible improvement after a couple of neck sizings, so I left it at that.

Every shot might be considered fire forming to some degree, the place where it is truly significant is with wildcats where the original case may be significantly different to the chamber, examples being things like the .243 Win versus the .243 Ackley Improved with the more squared off shoulders and increased case capacity so first shot with standard sized brass is blowing the case out to the chamber. Some chambers will need a more drastic approach such as jamming the bullet in the lands to hold it off the chamber shoulder or forming false shoulders. Rimmed cases make life a bit easier however how many people are wildcatting rimmed brass these days?

The important part is the consistency of the loaded round and I see no issues with just neck sizing and bumping when required versus full length sizing as long as you do either one or the other every time to keep things consistent. If I was a BR shooter I would probably be running my brass through a FLS die every time so I can chamber a new round as quickly as possible whilst keeping any disturbance to the rifle position to an absolute minimum. Sale applies to straight pull rifles which I always FLS when I am shooting and reloading for one.

Personally I would say experiment and use what does work for you both at the reloading bench and on the range.