Have a chat with a local friendly engineer who will probably have some 'Helicoil' inserts or 'Dodge' plastic types. See here:
http://www.helicoil.in/
You should be able to repair/replace you thread with one of these. You will have to find a suitable sling stud bolt first and then fit the suitable thread insert to suit. There are loads of these types of inserts on the web or evilbay!
Some more here;
http://www.insertsdirect.com/
Hope this helps.
MS