the rules say 16 OZ
1.4.7. Javelins must conform to all of the following:
1.4.7.1. Must also pass as a Class 3 Weapon.
1.4.7.2. The maximum weight is sixteen (16) ounces.
1.4.7.3. The minimum length is four (4) feet.
1.4.7.4. The maximum length is seven (7) feet.
1.4.7.5. Padded along the entire length.
1.4.7.6. Must flex less than 90°. This is an exception to Appendix A, 1.3.5.
1.4.7.7. Must have a yellow cover.
the PDF says 24 oz which is right ?