Increase in uressure for any one round as reoordecl on test copper. Pressure previously recorded on teet copper, Mean pressure recorded on uncompressed coppers, v. In plots 2 and ll, only positive v~-;lues of pt1 - Pm are used, Discussion. From plots No. 1 and No, 2 it appears that when loose mediUI!I CHliber gp_uges, h<-ving the nresent ...