No way I would shoot those loads in a 2 1/2 inch damascus gun. I'll bet the pressure they generate is above what most consider to be reasonable. The short chamber only makes it higher. The problem is that Federal doesn't publish pressures. We only know that it's below the 11,500 SAMMI standard. That sharp recoil is bad for the wood on your old hammergun. Clean them up with steel wool and shoot them in the 870. 
B&P makes 1 oz. and 7/8 oz. loads called Competition One that are about 6,500 psi and are readily available on the internet
Last edited by Hammergun; 11/02/25 06:54 PM.