NERF-compatible Grappling Hook remix with ring for string!!

update 04/12/2014: have now printed a test bit messy on the print but need to now test fire it to make sure it flys nicely this thing is a remix of http://www.thingiverse.com/thing:127124 I have added a little ring to the hook so you can attached a piece of string I haven't tried printing this just yet so its a work in progress hopefully it wont over balance the hook to much!!!