The Colt "E" size frame (as it is now called) remained essentially unchanged from 1908 until the early 2000s, and includes the Army Special, the Official Police, the Colt Officers Models, the .357, the first Trooper, and the Python. I don't know if the metallurgy changed over that period or not. Will an OP handle a +P load? No question about it. Some gunsmiths convert OPs and Troopers into (sort-of) .357 Pythons with a barrel change.