I'm converting a squad of Grey Knights from various Space Marine parts, using the Scout Heavy Bolter to make a psycannon. The main change I'm making to it is detaching the clip and reattaching it on the side. It's an unusually large cut and I'm wondering if anyone thinks that there's a better tool for the job out there than just a hobby knife (I'm not sure if it's large enough of a cut to warrant the GW hobby saw). (I do have a picture of just the uncut heavy bolter if someone wants to see it, but I don't think it will be necessary.)
Any help would be appreciated.