Armory Sponsor
Posted: 10/29/2008 9:36:34 AM EDT
|
Getting ready to load up some 223 for a OCW run and wondering how close the cases need to be to the same weight.
In a perfect world they would all be the same, but that just ain't gonna happen given the budget and standard manufacturing tolerances. Another factor - should the three-rounds-each of the different powder charges be loaded into the same weight cases or spread out over the entire range? Thanks for your time, OFG |
|
Quoted:
Getting ready to load up some 223 for a OCW run and wondering how close the cases need to be to the same weight. In a perfect world they would all be the same, but that just ain't gonna happen given the budget and standard manufacturing tolerances. Another factor - should the three-rounds-each of the different powder charges be loaded into the same weight cases or spread out over the entire range? Thanks for your time, OFG I sorted cases a few times and ran accuracy tests on sorted vs non-sorted and didn't notice any gains. I have since given up on weight sorting and focus more on shooting technique to improve my groups. |
|
I used to sort by weight. But, sorting by weight without going through a bunch of prior steps is a waste of time.
1. Clean/polish the brass. 2. Resize your brass (full length the first time anyway, even if your rifle won't need it every time. 3. trim the cases to the same length. 4. I even turned the necks down to a uniform thickness. After the four steps above the brass has the same OD from neck down, the same length and the neck walls are the same thickness. Therefore any difference in weight is case wall thickness which translates into a volume difference which would be a pressure difference on firing. Seemed to work for me years ago but I have not done it lately, I just sort by headstamp. |
| I did an experiment several years ago to determine just how much effect brass weight has on .223 loads. I used WW brass (sized, trimmed and deburred, primer pockets uniformed, flash holes deburred, and neck turned) , WSR primers, charges of RL-15 or N-550 powder weighed to 0.1 gr, and 75 gr A-Max bullets. Using the lightest and heaviest cases (sorted from 1000 once-fired I had on hand), I had two lots of 10 cases with a 3 gr difference in weight. The average muzzle velocity difference was 16 fps, just a bit more than the 12 fps due to 0.1 gr of powder. I choose to sort 0.5 gr lots of brass for my long range loads, but the effect will only matter at 800-1000 yards - the vertical displacement on the target from such a small velocity change is negligible at shorter distances. Unless you control all other sources of variation, the effect of brass weight is negligible. |
|
Thanks for all the feedback. This is my first experience with reloading. Lots of learning going on and this board has been a big help.
I am starting an OCW run and want to get all the variables out of the mix to the best of my limited abilities. Hopefully a good basic load will show up. Using new WW 223 brass, Varget, Rem 7 1/2 primers, and Sierra 69 grn HPBT. So far have done all the prep work tho I only turned the necks till they are running +/- .0005, not completely cleaned up all the way around, but better then out-of-the-bag. I imagine that the new will wear off pretty quick and case weighing won't seem as important down the road. OFG |
|
Quoted:
I did an experiment several years ago to determine just how much effect brass weight has on .223 loads. I used WW brass (sized, trimmed and deburred, primer pockets uniformed, flash holes deburred, and neck turned) , WSR primers, charges of RL-15 or N-550 powder weighed to 0.1 gr, and 75 gr A-Max bullets. Using the lightest and heaviest cases (sorted from 1000 once-fired I had on hand), I had two lots of 10 cases with a 3 gr difference in weight. The average muzzle velocity difference was 16 fps, just a bit more than the 12 fps due to 0.1 gr of powder. I choose to sort 0.5 gr lots of brass for my long range loads, but the effect will only matter at 800-1000 yards - the vertical displacement on the target from such a small velocity change is negligible at shorter distances. Unless you control all other sources of variation, the effect of brass weight is negligible. Great test! To clarify to the casual observer, however: this is all brass from the same manufacturer. These same results would NOT apply to an assortment of random headstamp brass, as internal case volume would vary much more significantly than in the test performed above. |
Armory Sponsor