750 
= bh = 
After the shot a dial depth gauge is used to measure the depressions 
in the diaphragms. Because the edges of the thin diaphragms assume a twist 
after deformation, a means must be used to hold these edges flat, 
Since the plates are not of uniform thickness, a correction factor is 
applied to the depressions. Diaphragms of lh-gauge thickness are corrected 
to 0,.085-in,. thiekness and 20-gauge diaphragms to 0,038—in. thiclmess. 
