This is a riser / Handle for a takedown bow with fiberglass limbs. It is modeled to receive the pair of bow limbs which I have, which I inherited from my Grandpa. Its slots are 1/4" by 1.5" and are 2" deep. I believe that plastic will take the strain just fine, especially with how thick I made it.

Want this 3D printed in steel? Look here: https://www.shapeways.com/product/6SNXGKV3B/bow-handle-1?optionId=121178777