I might be wrong (usually am) but I don't think those replaceable forcing cones are really any harder to wear out, they are just "replaceable". The cost to get them replaced is no cheaper than a new barrel. They are not even offered as an option anymore.
When my problems first started, my discussions with FA centered around the bullets I was using. I was told my both John Carey and Bob Baker that was the problem. My second barrel was fired only with FA bullets or CPC, both of which I was told would be OK in my gun. When the forcing cone was shot out of it too, in a very short time, that was when we started to look at the powder, which was Lil Gun.
Still, you DO need to use bullets of sound construction and hard cores to drive them at 454 pressures. That is why you will see much hotter loads listed in Hodgdon's manual for the FA jacketed bullet than you will for...say a Sierra 240 grainer.
Bob's advice to me, and it is good advice, is to load only to levels suggested by and for the actual bullet you are using. Do not substitute bullets of same weight/different manufacturer. That is why Hornady developed the XTP MAG.
They (Bob and John) say that the forcing cone will wear out much sooner if you use bullets that are not up to the pressures.
