Full Length Resizing

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ekp

Guest
I have read that a lot of competitors full length re-size. I always thought that after initial firing that neck sizing would give you a more accurate load. My question is ..is there any value to firing the brass first and then full length re-sizing or is there really no difference in using new brass and full length re-sizing.
 
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Typically, a FL die will be larger than unfired brass. If this is the case, little is accomplished by running unfired brass through one, unless it is the type that has an expander, which may be useful for making necks more uniform for their first loading, and if that is what is wanted, IMO an expander die and mandrel will do a better job. It should also probably be pointed out that much of the neck vs. FL lore came about from the use of very bad dies, which of course no competition shooter would use. Apples and oranges...What kind of dies are you using?
 
Boyd Allen said:
Typically, a FL die will be larger than unfired brass. If this is the case, little is accomplished by running unfired brass through one, unless it is the type that has an expander, which may be useful for making necks more uniform for their first loading, and if that is what is wanted, IMO an expander die and mandrel will do a better job. It should also probably be pointed out that much of the neck vs. FL lore came about from the use of very bad dies, which of course no competition shooter would use. Apples and oranges...What kind of dies are you using?
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I hate to admit it but since I do not compete I use Lee dies. Both full length and neck collet dies.
 
If the FL sizer is matched to the chamber (meaning slightly undersized by 0.005 - 0.001"), there's no reason not to. The old myth is case life is better if you only run the necks. We played this scenario out with our 6mm BR. Built in the 80's, we first only neck sized, then later cut a FL die. And guess what? Brass life improved and accuracy wasn't impacted.

And with a high pressure round like the PPC, you're much better off squeezing the whole shell.

-Lee
www.singleactions.com
 
Those lee dies will take the case back to factory specs which means your gun will work good and smooth. Neck sizing doesnt do that. So for not competing if your gun chambers the shell well dont change unless youre going to a redding set of fl dies. Going to the next step with custom barrels get a custom die made with it. A factory chamber factory gun will not gain anything by neck sizing itll only make your life harder since the chamber is not perfect. Save your money for ammo.
 
ekp said:
I have read that a lot of competitors full length re-size. I always thought that after initial firing that neck sizing would give you a more accurate load.
Click to expand...

Commenting on your first sentence, this is generally true for factory chamberings. Factory chambering are based on an industry accepted set of dimension standards set by the Sporting Arms and Ammunition Manufacturing Institute-SAAMI. Within these dimensions are 4 limits-maximum cartridge, minimum cartridge, maximum chamber and minimum chamber. From maximum chamber size to minimum cartridge size in some standards are about 0.010". Whereas on the other factory extremes of minimum chamber size to maximum cartridge size is generally about 0.002". Understanding this fit/misfit just neck sizing after the first firing will give a better fit, and accuracy, for subsequent firings.

This is not the situation at all in benchrest cartridges and chamberings where the desired fit, after resizing, is about 0.0003"to 0.0006". Therefore the fit of the f/l die, if done properly, will resize the entire cartridge body only just enough to allow the cartridge to reenter the chamber smoothly.

In the BR world several years ago, simply neck sizing every 2-4 reloadings, then f/l sizing only when the brass got too tight from work hardening and spring-back. Today, with the extremely high chamber pressures most BR shooters loadings generate, a vast majority of BR shooters f/l size each time. This is why, in benchrest chamberings, it is very important to have a precise match of the f/l die used. A common mistake of many new BR shooters is not having that precise fit. Selecting a quality gunsmith who understands this situation is very important if you have your work done by someone other than your self. Doing the chambering work yourself, you will quickly discover the tribulations caused by a reamer/sizing die mismatch.
 
JerrySharrett said:
Commenting on your first sentence, this is generally true for factory chamberings. Factory chambering are based on an industry accepted set of dimension standards set by the Sporting Arms and Ammunition Manufacturing Institute-SAAMI. Within these dimensions are 4 limits-maximum cartridge, minimum cartridge, maximum chamber and minimum chamber. From maximum chamber size to minimum cartridge size in some standards are about 0.010". Whereas on the other factory extremes of minimum chamber size to maximum cartridge size is generally about 0.002". Understanding this fit/misfit just neck sizing after the first firing will give a better fit, and accuracy, for subsequent firings.

Years ago I had a push feed Model 70. I could not understand why I would get consistent 3/4 groups at 100 with new brass but after neck sizing with a Belding and Mull straightline reloading tool the groups would open up significantly. Then I noticed the brass once fired was out of round at the base. I took it to a gunsmith and he told me that the chamber was actually oversized and the extractor was probably pushing the cartridge off center for firing. The only way to solve the problem was to index the rounds which I did not want to do. He told me it was probably with in the specs from the factory. I never pursued it and now the rifle is my sons. Reloading for him the once fired brass would get stuck in my F/L die. Of course I never saw this because back then all I had to reload with was that Belding and Mull tool.
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