More infro reported in 2016
Bismuth 2 1/2 @ 1400 fps 1 1/16 oz. - 9800 psi;
1 1/8 oz. - 10,000 psi
Tungsten Impact 2 3/4 @ 1400 fps, 1 1/4 oz. - 9900 psi;
1 3/8 oz. - 11400
1925 - 1954
2 1/2 & 2 5/8 12g maximum service load was reduced to 3 Dr. Eq. with 1 1/8 oz. shot with a mean pressure of 3 1/4 tons by LUP = 9,800 psi by Burrards conversion.
The 2 3/4 12g max. service load was 3 3/8 Dr. Eq. with 1 1/4 oz. shot with a mean pressure of 3 1/2 tons = 10,640 psi by Burrards conversion.
The conversion provided by the Birmingham Proof House in 2001
2 1/2 / 3 tons = 8,938 psi
2 3/4 / 3 1/4 tons = 9,682 psi
3 / 3 1/2 tons = 10,427 psi
