Measuring Case Capacity

[Grump]

I've been fiddling around with comparing brass types and found that my guesstimate of H2O capacity by filling the case and dumping the water into the scale's pan is just not even close enough.

Weighing the .308 case empty, then again when filled with water, yielded 2.5 more grains of water capacity. So, my LC86 M852 brass, sized and trimmed to 2.01 (and fired three times) holds 55.0 grains of H20.

FA63 MATCH cases prepared the same way are 6.2 grains heavier empty, but hold only 0.2 grains less water at 54.8 grains.

What case capacities are youse guyz getting with Winchester, Remmie, FGMM, and Lapua?

Thanks!

 

[Unsichtbar]

Re: Measuring Case Capacity

Winchester - 56.9gr
IMI Match - 54.1gr
Federal - 54.4gr
Lapua - 54.5gr
LC 1991 - 54.5gr
Water Volume .308 Cases

 

[DocB]

Re: Measuring Case Capacity

Grump,

Measure the case capacity after you've fired the case in your rifle. It will be different from new cases since it will depend on how the chamber is cut. The fired brass data gives me better results in QL. I use a clean case with fired primer, weighed empty; then with water. The water meniscus should bow up over the top edge of the neck, not level with the top edge.

HTH,
DocB

 

[memilanuk]

Re: Measuring Case Capacity

Winchester ~57.1gr
Lapua ~55.7-55.8gr

As we've discussed before, Grump, I put a drop of dish soap in the water I use, which lets me get a fairly flat meniscus.

Another place I've asked about this yielded a suggestion to use wooden golf tees in the flash hole rather than a spent primer due to variations in the volume the internals (and residue) of said primers renders. Haven't tried it yet, but it makes a certain degree of sense. After you water weigh a few cases you'll see how when chasing the meniscus trying to get it consistent just a very small amount of water makes a noticeable change in the water weight.

 

[KQguy]

Re: Measuring Case Capacity

I have literally drove myself crazy weighing brass,checking h2o capacity,and all the other methods of sorting brass.In my opinion,the best way to sort brass,is at the range.Whenever I shoot,I keep track of every shot.I put fliers in a pile,ones that were 3/4-1 moa high in a pile,and and rest that were spot on in a pile.I can keep track of my brass out to 500 yds.,that's about as far as I can see bullet holes on target with my scope.This is the best method I have found to sort brass,"the target tells the tale".