Originally Posted by j_unzicker
No I haven't compared...shouldn't they be about the same? they are same brand. Is there a tool that you use to compare them? What's the proceedure?
You can simply weigh the brass either with primers in or out and see if they are within a couple of grains, or, the more accurate method, is to weigh the brass empty and record, then fill with water and weigh again. Subtract the empty case from the filled case and that will give you the case capacity in grains of H20. Brass of even the same brand can often be different weights, thus having different capacities. It would make sense that plated brass would have slightly less case capacity than not plated, although, that by itself shouldn't make a significant difference since the plating is so thin. Another possible pressure problem could be excessive case length causing pressure as the bullet leaves the case mouth into the throat. Check you case lengths. Neck thickness can also cause the same pressure problems if excessive, but that is unlikely if it is factory brass in a factory chamber. I am assuming that your pressure difference is occuring when all the other loading variables are the same? i.e. bullet seating depth etc............Rich