Of course it's an abrasive, it's just very, very fine. JB Bore compound or Bore Bright which are meant for bores will do the same, it removes very slight amounts of metal, not enough to cause harm when used properly, just smoothes the rough edges and generally makes the bore more bullet friendly and cleans easier.

If you go over to AR or Benchrest Central, there are threads on extended use of JB bore compound, there're shooters that have been using it for over 20yrs in the same bore with no degradation in accuracy and they swear by it.
I'd give you a bunch of links, but my cable modem is in limp mode, I'm getting less than dial-up connection speeds @ 5kbps, this page takes about a minute to load!!

Tim