Ok, so it seems there's no way to export or import a *.nif for this build of Blender *bangs head on desk*, but I did get the bow nicely rigged to a custom skeleton. Only downside is I don't know if an extra bone will be needed in each limb to prevent mesh distortion, using two per limb atm. Thanks Ghosu, that weighting guide was very useful for fixing the issues caused by the auto-weighting! Next job, working on the UV map unwrapping of the mesh, been holding off on that in case I had to make mesh alterations. Edit: Found a handy forum post that helped me get the mesh out of 2.6 and into 2.4, also got the UV map nicely laid out now too. Now to get the bones in from a stock bow and work out how to weight paint in 2.4 ^.^ Edit 2: As of about 10 minutes ago, I got her in-game and seems to be only a slight rigging issue where the limbs have a slight buckle in them when the bow is fully draw. She's a monster though, may have to look into a mob that changes the bow's position on the back slightly as the bottom of the bow is nearly scraping the floor! Still need to make a new texture as I altered the mesh somewhat to fix a few flaws and have also learned never to trust auto face gen, half the faces were backwards >.< but thanks again for the advice, it got me on the right track!