I know there are alot of cockers out there using S.S. hammers, and the bonebrake and some upgraded angels, but read the bad...
We all know that the stock brass hammers sometimes start to leave little snowflakes of brass in the hammer bore, and so lots of us switch to an SS hammer that won't wear out. But that's BAD!
I've been told that the hammer in an angel does not rely on the interior wall of the hammer bore for guidance- the ram shaft keeps it as straight as it needs to be. The hammer will only brush against the inner walls of the hammer bore on rare occasions (and sustained rapid firing), or when there is a problem with ram alignment/wear. An overpressurized LPR will also cause the brass hammer to wear out due to a mushrooming effect that will cause the end of the hammer to expand (flatten out) and thus rub on the inner walls.
If your brass hammer is wearing out fast have the LPR and ram checked out. Switching to a SS hammer is treating the symptoms not the problem. "He's Bleeding! Get a bucket".
Furthermore, if you do have an alignment/pressure problem that new stainless steel hammer CERTAINLY won't wear out from rubbing on the hammer bore interior- but it will chew up the aluminum bore quite nicely. And let's not forget that brass-aluminum has a substancially lower coefficient of friction than SS-aluminum.
I don't think it changes any performace, and like i said its used alot, but also if your getting brass shavings, then theres somin wrong.