cal30_sniper
Member
One also needs to take into account the shear stresses involved, defined as one half the difference between the principle stresses. In this case, the principle stresses are the hoop stress and the radial stress. The Shear Yield Stress (SYS) is approximately 75% of the Tensile Yield Stress (TYS), and the Ultimate Shear Strength (USS) is approximately 58% of the Ultimate Tensile Strength (UTS).
Given those conversions, the SYS and USS of the steel in question should be about:
SYS: 43.5ksi
USS: 82.5ksi
Given the hoop and radial stresses I already calculated, below are the shear stresses for each rifle at each location:
Inner Region:
7.62x54R Mosin: 57.1ksi (70% of ultimate)
M2 Bannerman: 61.9ksi (75% of ultimate, 108% of Mosin)
.30-06 Bannerman: 74.3ksi (90% of ultimate, 130% of Mosin)
Middle Region:
7.62x54R Mosin: 12.1ksi
M2 Bannerman: 23.0ksi (190% of Mosin)
.30-06 Bannerman: 27.5ksi (230% of Mosin)
Outer Region:
7.62x54R Mosin: 5.1ksi
M2 Bannerman: 11.9ksi (233% of Mosin)
.30-06 Bannerman: 14.3ksi (276% of Mosin)
So, in the inner region of the .30-06 Bannerman, not only are you dangerously close to the Ultimate Tensile Strength, you are dangerously close to the Ultimate Shear Strength as well. And that's under perfect conditions without imperfections or stress risers.
Given those conversions, the SYS and USS of the steel in question should be about:
SYS: 43.5ksi
USS: 82.5ksi
Given the hoop and radial stresses I already calculated, below are the shear stresses for each rifle at each location:
Inner Region:
7.62x54R Mosin: 57.1ksi (70% of ultimate)
M2 Bannerman: 61.9ksi (75% of ultimate, 108% of Mosin)
.30-06 Bannerman: 74.3ksi (90% of ultimate, 130% of Mosin)
Middle Region:
7.62x54R Mosin: 12.1ksi
M2 Bannerman: 23.0ksi (190% of Mosin)
.30-06 Bannerman: 27.5ksi (230% of Mosin)
Outer Region:
7.62x54R Mosin: 5.1ksi
M2 Bannerman: 11.9ksi (233% of Mosin)
.30-06 Bannerman: 14.3ksi (276% of Mosin)
So, in the inner region of the .30-06 Bannerman, not only are you dangerously close to the Ultimate Tensile Strength, you are dangerously close to the Ultimate Shear Strength as well. And that's under perfect conditions without imperfections or stress risers.