"The Elastic Strength of Guns" 1916, Alger, as used by the USNA in class, p28-- for a simple hollow cylinder, R=outer radius,r=inner radius, maximum internal pressure allowable=P.Then P= 3 times the quanity of(R squared-r squared)divided by (4 times R squared +2 times r squared).All then multiplied by the elastic limit of the material under tension.