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Posted: 3/9/2009 8:14:08 AM EDT
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I purchased a bunch of once fired cases w/crimp and now I am resizing them. My reloading manual lists the max length of the case as 2.494. Most of the cases are measuring between 2.49 and 2.494 but some are measuring as short as 2.48. Now I realize that cases over 2.494 need to be trimmed but are the cases that measure a little short still ok to reload? At what point is short too short? thanks
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A little short means less neck to hold the bullet.
How much is too much? I wouldn't loose sleep over it........but, that's ME. Aloha, Mark PS............I don't have a book to tell me the min lengths of certain cartridge cases. My books show me the max. lengths. So, OK.........I've thought about it.........without getting into heavy math and statistical significance......."When would I loose sleep?" Given the max length for a .223 Rem is 1.760" And, trim to length is 1.750"............that's a .01" difference and look at the neck length of the .223 Rem. So........for the 30-06 the max length is 2.494" Now, if I were to reduce that measurement by .01"...........I'll get 2.484" and look at the neck length of a .30-06. What do you think? Then, I have shot .223 Rem brass as short as 1.74x" so.........whatever. |
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Humm........I never really thought about the question so hard. Much less, to put it into writing.
I guess.......a measurement of .01" shorter then the published max........might be a "fast rule of thumb." Then again.........what do I know? I could be all wrong about the entire thing. Someone with a book, might just quote the book and tell eveyone "I'm full of it." Aloha, Mark |
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Here's what I do. After I've collected several hundred rounds of good range brass and have cleaned them.
1. I next size them all. 2. I sort them into lots by Mfg. 3. I trim to length with LEE trimmer tool. Makes very uniform trim length. 4 I debur the flash hole w/ flash hole deburing tool. 5. I use a neck turning tool to uniform the necks. Most people don't do this step but it makes for much more uniform brass. Therefore more uniform crimp and minimal standard of deviation in velocity. 6. I sort by weight next. 30-06 brass can range from 185gr. to 206gr. I've found that a 15gr. variation can cause a group to change vertical point of impact by 2" at only 100yrds. You decide if this important to you by running your own test. Note step #5 helps to make weight range more uniform as well. Some will say the last 3 steps aren't necessary and are only needed for bench rest shooting. I've never shot bench rest. I just desire the most accurate ammo I can assemble! But to answer your question about cartridges that are shorter than minimum length by more than .002 I just use them for practice shooting offhand. Minimal use of these won't harm your chamber. |
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