I found a good load for my .308 175 smk, with fed. brass, and 43.7 varget. I decided to weigh the amount of h20 that fits in case. For new fed.brass I get average of 52.6 grains. I also weighed capacity for new winchester brass, the average is 54.5 grains. Almost 2 grain diff. Does this seem about right? Is this considered alot? Or can I throw in the same powder charge in the winchester brass as i did for the fed brass?
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H20 capacity diff. please help!
- Thread starter gregpo
- Start date
Re: H20 capacity diff. please help!
Winchester brass is thinner, therefore has more internal volume.
Winchester brass is thinner, therefore has more internal volume.
Re: H20 capacity diff. please help!
gregp,
No, not that much. Maybe 2 tenths of a grain. The rule of thumb is a tenth of a grain for every grain of case weight, for the same brand of case and a maximum weight difference of 10 grains. Increase charge for lighter cases, decrease it for heavier cases. This is for case weight, not internal volume weight.
Folks are better off starting low and working back up for different brands of cases. Besides weight and internal volume differences between brands; bullet neck tension and case head thickness differences will alter pressures.
HTH,
DocB
gregp,
No, not that much. Maybe 2 tenths of a grain. The rule of thumb is a tenth of a grain for every grain of case weight, for the same brand of case and a maximum weight difference of 10 grains. Increase charge for lighter cases, decrease it for heavier cases. This is for case weight, not internal volume weight.
Folks are better off starting low and working back up for different brands of cases. Besides weight and internal volume differences between brands; bullet neck tension and case head thickness differences will alter pressures.
HTH,
DocB
