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Posted: 3/11/2015 10:55:33 AM EDT
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I'm a bit of a noobie to reloading, and I've always just reloaded blasting 223 ammo for my AR, and I'm slightly confused.
Last night I worked up loads with my new Tikka T3 in 243 and found that 36.6 grs of 4064 works best with FL sized Winchester brass and a 87 gr Vmax. I have both a FL and neck sizer die and I'm unsure how to proceed from here? Should I neck size the fired brass and leave the unused brass FL and load it? Is there going to be a measurable difference between brass that has been FL sized or neck sized? Furthermore, will there be a noticeable difference between brass that has been fired once vs. twice? |
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I haven't had time to run an experiment on differences in results between full length and neck sizing, but there is some reason to believe that neck sizing only could improve accuracy (by setting effectively zero headspace). For an autoloader like your AR, you will always want to full-length resize to ensure proper function. I neck size my bolt gun brass with a collet neck size because you don't need to lube them, and it does less cold work on the brass. After a few firings with neck-sizing only, you will likely eventually need to full-length resize to set the shoulder back, because the fit in the chamber can get very tight.
The variables I'm interested in looking at with respect to FL vs. collet neck-sizing are accuracy, brass life, and brass growth (length), but I haven't had time to work up and execute an experiment on it. |
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After the case has been fired in the desired gun, it matches the chamber of that gun. You can now use the neck sizing die as long as the ammunition will only be fired in that gun (not a semi-automatic). This will give you longer case life and should/could give you better accuracy. There is a hell of a lot more than neck sizing involved in better accuracy but it is one part of the equation.
At some point it is likely the cases will start to be more difficult to chamber. Assuming you are trimming correctly and seating your bullets to the correct depth, you will need to do a full length resize and then go back to neck sizing again. |
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