Posted by Drew Hause on November 27, 2014, 11:34 am, in reply to "20 in 12 Pressure"
Courtesy of Sherman Bell back in 2006 for GaugeMate
A Winchester 20-gauge A-A Sporting Clays factory load of 7/8 ounces of #7 1/2 lead shot, fired in a Silver adapter, gave a velocity of 1319 ft/second and developed a pressure of 7700 psi. The same 20-gauge load fired in a Go1d adapter gave a velocity of 1324 ft/second and developed a pressure of 7800 psi. With all 0-rings removed from the Gold adapter, per your request, the velocity was 1302 ft/second and the pressure was 7900 psi.