Weighing Unprimed Cases

M

Mad_Max

Inactive
I've been told to weigh my cases for consistency in groups. So I fire formed and neck sized and trimmed all the cases to the same length and de-burred them and cleaned the primer pockets and then cleaned the brass in RCBS corn cob media and then weighed them and here are the results of 57 casings with a 3.2 GR. difference from the lightest to the heaviest case.

.308 Win. Remington Case Weight

165.2 165.4 165.4 165.4 165.5

165.5 165.6 165.7 165.7 165.8

165.8 165.9 165.9 165.9 165.9

165.9 166.0 166.1 166.1 166.1

166.1 166.2 166.4 166.4 166.6

166.7 166.7 166.7 166.7 166.8

166.9 166.9 167.0 167.0 167.1

167.1 167.2 167.2 167.2 167.2

167.2 167.3 167.3 167.4 167.4

167.4 167.5 167.5 167.6 167.6

167.8 167.8 167.8 168.0 168.2

168.2 168.4
 
The reason to do this, I believe, is to check for volume. How much variance you accept, depends on how far you shoot.
 
Weighing Cases

I would think that the closer the cases weigh to each other the more consistency you'd have in shooting. I shoot as far as 600 yards. Never tried 1,000 yards.
 
I believe, the belief is if they weight more, they have more volume, which effects pressure. You want to be consistant. Filling with powder, then measuring powder would take forever. Some champion benchrest shooters might though.

Higher end brass like Laupa or Norma, is probably more consitant. I shoot lots of remington. I have seen a difference, but I am not shooting 600 yards. My home range is 100.
 
To see if it is worth the time take the 10 closest cases and load them and 5 of the lightest and 5 of the heaviest and shoot two 10 shot groups.

If one looks like a shotgun pattern and the other one hole then you'll know it's worth it, if you can't tell the difference don't waste the time in the future.
 
I believe, the belief is if they weight more, they have more volume, which effects pressure.
Click to expand...

If the mass of the material is the same and they have the same external dimensions, any additional weight would reduce internal dimensions/volume. Of course any difference in volume will effect pressure, dependent on variables.
 
If you read up on long range shooting, some folks want every round identical. Longrangehunting, is a good place to read up, and tons of articles too.
 
Weight Grouping

In my experience if I take 5 or 10 of the lightest or 5 or 10 of the heaviest, I will still get consistent groups. It's when I take some light cases and mix with heavy cases that groups spread. I have separated cases into one grain batches and shot over the chrono and got the average velocity for each group. The group size will be fairly equal, but average velocity will increase by about one percent for each one grain variance of the average group weight. In my experience what the case weight is is not as important as all being the same weight in that group.
 
MAD MAX: Do you currently weigh out & segregate your projectiles?
Do you currently reload only 1 case brand or multiple brands?
I would have a tendency to believe that you would see a difference in
accuracy & / or precision @ 600 yds weighing & segregating both the
jectile & the cases. pro
 
Weighing Cases

Yes I weigh my bullets also and I'm going to separate them and match them up & chronograph them and also check for group size.
 
MM, please post up the results. This should make for a very interesting & informative experiment. I'm thinking that at 600 yds it will make a noticeable difference.
 
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