Did you scape away the coating to see the rust, or are you just seeing a rust-like texture underneath it? Rust converters do nothing to change the pockmarked look of the piece.
As for getting the coating off, the MSDS says it's a vinyliden-acrylic copolymer which will thermally degrade at about 350 F, so the smell will be so bad you better don't get caught by your significant other doing it in the kitchen range.
My recommendation would be bead blasting followed by reblue.
I used to love being able to hit hard at 1000 yards. As I get older I find hitting a mini ram at 200 yards with the 22 oddly more satisfying.