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Posted: 1/19/2010 3:28:27 AM EDT
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After about a year of reloading 223& 556 I have begun to weigh some cases after triming and sizing to 1.751.
I just finished 200 Win 223 cases and have weights from 91.7 grains to 94.1 grains without primers. Im using 23.5 grains of Varget and WSR primers and shooting five round groups. Using 77 grain Nosler CCs Using the lightest cases im getting 3/4 groups but as I go to the heavier brass the groups grow. I know testing, testing and more testing will find the answer, but there has to be a curve where less powder or more powder will work. Im going to load all of the cases this week. Does any one have any suggestions on loading the heavier cases such as when does the amount of powder and weight of case catch up with each other? Thanks because math was tough on me in school with writing skills a close second. Dave |
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If you're using one charge weight, that is the source of your problem. The weights of those cases are close enough for practically any application.
How many groups have you shot to determine the light cases are more accurate? One or two groups is insufficient to come to your conclusion. Take the lightest case and the heaviest case from your batch. Weigh them empty, then fill them with water and weigh again. Calculate the weight of water each case will hold. This will give you a good measure of the internal capacity of these cases, better than weighing empty cases. |
When I weigh the cases without the primers the water runs out J/K
I have only tried this thinking at the range three times and it has worked out the same. I have measured the web thickness and the lite case web was 0.188 thick and the heavy one was 0.195 thick. I guess im over thinking pressure inside the case. I will move powder weight around and test it out. Thanks. |
| 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. |
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