Annealed brass opinion
- Reloading Depot
- 121 Replies
Yes, quite a few people have done so actually, and I'm just one of them. It can be very obvious when comparing the likes of Winchester .308 brass to LC .308 brass. Winchester brass is quite a bit lighter with much more case volume than other brass. For example, when I weighted 10 random Winchester .308 brass I have, the average was 158 grs with 57.3 grs H2O of volume. For 10 of my Lapua .308 brass, the average was 172 grs in weight with a an average case volume of 55.9 grs H2O. If one takes the individual weights and volumes and graphs them, you can see the correlation, though there not a direct correlation from case to case given variations in web thickness. The same relationship for weight and case volume can be seen even from one lot of brass to another as can be see in data that came from Peterson Cartridge Co. here:Has anyone actually tested and documented heavier cases having lower H20 capacity? It would make sense and the expected result, but I just haven't ever seen anyone post having done so. I have checked a few cases when I was making custom 9mm sabot ammo that went 2,417fps a few years ago since that's a ugh, not well documented process... But haven't seen anyone pull say 20-30 cases that are close in weight and of the same brand and caliber etc. and then another 20-30 that are heavy by comparison and H20 capacity test them to actually see what the statistically relevant results are.
In my own testing I've seen enough difference within a single lot for weight and volume where I weighed my Lapua brass (see below) and took 5 of the heaviest and 5 of the lightest and compared case volume, loaded and fired them to see the difference in velocities. Interesting to me, there was enough difference in velocity between the two sets to make a significant difference in vertical dispersion at distance. When I fired the other cases of the same weight, I got really good SD's and ES's and groups on target were excellent. . . and each of those two sets of outliers were different, they too performed well. Though those two sets were only 5 shots each, they were loaded and shot a second time to get a little more confirmation on the results.
So, based on what other's have found for sorting cases and what I've found in my own experience, that it does pay to weigh cases and cull out the outliers. AND. . . BTW, I also found this to be helpful for weighing primers when I did the same kind of test.