Your right, I used diameter and not radius. .766 pounds. Which make the pressures involved with wet news paper as wad in a blank even more of an eye opener.
The article says the 1971 crusher test results were used to create the N-SSA tables. The article states that prior to the 1971 crusher tests the rule was maximum safe loads allowed were 1/2 of service load for a given piece. Crusher tests are time consuming, so the test conducted in 1971 were limited in scope. In 1971 they did not have Cannon grade powder available to test. Those test in 1971 were the test that were used to develop the N-SSA Load. If you wish to learn how those tables were created from that test data, I suggest you contact Matt Switlik and question him.
In the mid 1980's Switlik acquired piezo electric testing equipment to do pressure testing and in 1986-87 testing was conducted. Cannon Grade powder was available then for testing. The results recorded with the piezo electric pressure equipment were compared with pressure tests conducted by the Manufacturers and the Military. Installing the transducer required required drilling a hole in the barrel over the chamber and installing the sensor. Switlik did not test a smooth bore as one wasn't available for installation of the sensor.
There is a lot to be learned from from this article and it will help you formulate your questions for when you contact Switlik and learn how the tables were formed. For 3 bucks what's to lose?
Victor, I really think you should contact Switlik with questions you have about the safety of N-SSA and AAA rules.
