I'll agree with woogie on this one, you should do some more research on how this is done before just starting a topic. However, IMO, I would shape it out of a dense foam since it's easy to work with. Cut it in half to shape the internal parts for the trigger group and then coat the exterior with a fiberglass or epoxy shell to hold it together. Is this a BASR or a gas?2 - If you want to tell someone to do a search, you must also provide an answer to their question. If you cannot, then do not post on the topic. Brief responses only saying to do a search will be deleted.