Cybin,
If the rail is really epoxied to the barrel, then don't try to saw it off. Almost all epoxies (including the wonderful JB Weld) are simply resins and hardeners that will soften to a paste and come off easily if they are heated to about 250 degrees.
I have been told that applying this heat, and wiping off the epoxies, does not damage the bluing at all.
Please go to Board called Gunsmithing, and go back through the post subjects until you find a couple on JB Weld or other epoxies. Read up on them and go forth.
Hope this helps.
Mannyrock