You did good! That is a really nice gun. With minimum wall thickness of .28/.30 I stay under 7500 psi and usually target 65 to 7000 psi. My Edward Whistler back action hammer gun with minimum of .34 is a great shooter with 1 oz shot at these pressures. RST or hand loads with Clays, WST or American Select work well for me.
I presume you meant to out a 0 in front of those numbers as .028,.030 & .034. A barrel with a minimum wall of .28" would truly be a Bear.
The actual max pressure has little affect on the barrel down where the minimum thickness is found. In fact if you shoot the same amount of shot to the same velocity in lkoads with varying max pressures the pressure will be a bit lower "Down the Barrel" a ways with the higher max pressure load. Pressure in a gun barrel is always in the form of a Curve & the max is hit inside the chamber & falls off quite rapidly.
