Ok, why the water and the salt to determine equivalent grains of Varget. Why not just leave the primer in and fill the case up with Varget and then measure the weight of the powder?

With my .308, I found Federal brass would load 2 grains or so less than Winchester or Remington brass.

good point Slim, a very good point indeed.

Doh

Thanks Fn!

When I found the wide variety of used brass I saw an opportunity to test the often quoted admonishment to always adjust loads for different brass and especially for "military" cases as they are "known" to have less capacity. Sharing my inexpert attempts to replicate experiments carried out by others I sized, trimmed and did the measurements. The water volume was a flop for a number of reasons, some that are mentioned by others above. I actually thought about using Varget but, as an extruded powder, it packs differently for every drop and the potential for spillage and waste was an issue. I chose fine salt because it packs more uniformly, who cares what you spill and I could easily verify if any was left in the case. These "salt" comparisons show maximum of 4% spread lowest to highest weight and an average weight of 33.38 grains. The standard deviation is 0.46 grains. Varget is 0.85 the weight by volume of the salt (28.7 grains fills the Hornady case.) This equates to a powder standard deviation of 0.39 grains approximately. The two definite military cases were the LC and IVI, both stamped with the NATO cross in a circle. These had the highest and third highest case capacities. My conclusions are:

1. The differences in cases is not as great as I thought but enough to confirm caution when loading at maximum published loads in different brass.

2. The case (pun intended) for lesser capacity in military cases was not proven for the two small samples of the military cases I tested.

3. I need to read more about water volumes.

4. I can use fiddling around with my reloading "stuff" as another excuse to avoid chores :-).

This is what makes hand loading so interesting to me and I think to others. If anyone wants to replicate my little experiment I will send them one of each case, all 10 of them, at my expense with the only stipulation that they make the same offer to others when they are finished with them.

Mac, I particularly like conclusion #4!

I like to try to understand all this stuff too and appreciate your efforts.

I find that brass is a first level contributor to group size and changes in POI. When I first started reloading, I mixed Winchester and Remington brass and couldn't figure out why my rifle wouldn't group consistently. Then one day I noticed a 5-shot group with 2 fliers was shot with 3 Rem and 2 Win cases. When I sorted the remaining shells by brass manufacturer, my group size and POI became consistent.

pump, I can't take credit this is listed in a sierra manual as an "accuracy" load what do you know they were right!