Not to rush or hurry things but I’ve just cut-up an exceptional pair of Oryx (gemsbok) horns while taking a brake, not sure why though. Anybody knows if it would work as backing? It sure feels like it (strips about 2” wide over 41” long.) If possible I’ll only try it after I created my first “shooter”.

Horn is usually used on the belly of the bow limbs and the limbs are backed with sinew to make a composite bow. Horn is much better on the compression side of the limbs than on the tension side. This site will give you a fair explanation.http://www.primitiveways.com/pt-composite_bow.html

If it's like most types of horn then it's composed of a protein called keratin , and it's probably too brittle for backing material . How about some hippo rawhide ? That would be some tough stuff .