weighing LC virgin brass
- Thread starter rebs
- Start date
Size and trim first. Does'nt take much of a neck trim to make
one grain of chips. Being LC brass, it would'nt be uncommon
to have neck lengths all over the place and skewing your weight's.
As it is, wet weighing is more accurate, but for general use and
scale weighing, I use a 1/2 grain spread after the brass has been
processed and ready to be primed.
one grain of chips. Being LC brass, it would'nt be uncommon
to have neck lengths all over the place and skewing your weight's.
As it is, wet weighing is more accurate, but for general use and
scale weighing, I use a 1/2 grain spread after the brass has been
processed and ready to be primed.
jepp2
Gold $$ Contributor
When I weight sort brass, I weigh some to get an idea of the high and low I will end up with. Then I take masking tape an put it on a yardstick. Starting on one end, I mark the lowest case weight, and every inch mark 0.1 gr heavier. Then I start weighing my brass and stack them behind the mark reflecting their weight. When I finish, I have all the brass stacked in a "bell curve" fashion. I can fill my containers (normally MTM 50 round case guards) with brass starting at one end and working toward the other.
This give me a sort that best matches my brass weight. If I am weighing a much larger quantity, like 1K or above, I just mark containers in 1.0 gr increments and weigh and toss them in the container marked with their weight.
ronemus
Gold $$ Contributor
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 .223 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. I also shoot .284, and because the brass is twice as heavy I batch in 1 gr lots.
AckleymanII
Gold $$ Contributor
I put a heavy chamfer on the case mouth after a neck sizing, but prior to doing that, I grab them by the hand full, case head up, cull out the pieces with off center flash holes! Some years are very bad with off center flash holes and these end up breaking de capping pins.
Wow. I've never noticed LC flash holes being too bad. Now GFL/Fiochi brass? Terrible.
AckleymanII
Gold $$ Contributor
Assume nothing on those off center flash holes, best to be under good light, and possibly a large magnifying glass. Also, inspect for LARGE burrs inside the case around the flash hole!
Weight sorting .223/5.56 brass?
How many times do people claim that deburring/trimming removes a bunch of weight?
Take a piece of brass. Weigh it. Then trim off 1 grain of weight. How much did you trim?
I took one piece, 1.758" OAL that weighed 101.653 grains, trimmed off about 0.010" and lost 0.188 grains.
Trimmed another 0.010" (now 1.738" OAL) and lost another 0.185 grains.
Try it. One grain is probably going to be a trim of over 0.050"
Another thing you hear a lot is to wet weigh twice or third fired brass since it will hold more water after each firing until fully expanded.
Try it. Virgin brass water weight, once fired (keep track of the same case
), twice fired, 3rd fired water weight trimmed to same length, and resized for each measurement?
How much water capacity is gained?
How many times do people claim that deburring/trimming removes a bunch of weight?
Take a piece of brass. Weigh it. Then trim off 1 grain of weight. How much did you trim?
I took one piece, 1.758" OAL that weighed 101.653 grains, trimmed off about 0.010" and lost 0.188 grains.
Trimmed another 0.010" (now 1.738" OAL) and lost another 0.185 grains.
Try it. One grain is probably going to be a trim of over 0.050"
Another thing you hear a lot is to wet weigh twice or third fired brass since it will hold more water after each firing until fully expanded.
Try it. Virgin brass water weight, once fired (keep track of the same case
), twice fired, 3rd fired water weight trimmed to same length, and resized for each measurement? How much water capacity is gained?
Ned Ludd
Silver $$ Contributor
Weigh as many cases as you feel comfortable doing, but 50 to 100 cases should be plenty. After recording the weight for each case, put it [in order] into a reloading tray so you which case weighed how much. Next, look at the recorded case weight values. Find the total range of all the weighed cases and choose a couple likely points to use as cut-offs. Divide the cases into three groups; light, medium, and heavy. This will almost always result in less case volume variance per weight group than if the cases were not sorted at all.
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