I've been looking at a tube gun Eliseo R5 in 6mmBR in my future. I was wondering if this could also be used as a 308 win rifle if I got a barrel for it. I know the Eliseo R5 is meant for the 6mmBR and comes with magazines and sled for the 6mmBR cartridge, but could one possible run it as a 308win single loading rifle with just a barrel swap? or would I need to get a sled made for the 308win?