No experience with the 9mm convertibles.
One time I loaded up some 9mm 115gr FMJ in 38 Special cases. I shot them through a 4" GP100. The accuracy was off a little. I managed about 5=6" at 25 yards, where I was closer to 3" at 25 yards with the .357" bullets.
I was not shooting off a bag or anything, just standing, mod-weaver.
