This proofing must assuredly have been done with black powder. With charges running from about 8 drams & 2 oz of shot to over 10 drams with more than 3 oz of shot it is simply inconceivable that Smokeless would have been used in these amounts. Particularly if the double or triple proof were used one might think this would have been adequate for the 3" chambered gun.

Miller/TN
I Didn't Say Everything I Said, Yogi Berra