The muzzel is the end of the sprear gun barrel, opposite the handle. Its where the spear goes through.
the wishbone is the piece of chord, wire, steel fixed tot he 2 ends of the gun rubber elastic. this is what attacheds the rubber to the spear.
a rail barrel is a barrel that has a grooved V in the top, upon which the spear lies. The rail keeps the spear running true down the barrwel upon firing. It prevents whipping of the spear and nmakes it more accurate.
go to sites like www.roballen.co.za por freedivers.co.za. they have info on there.