Lead is hazardous to handle without proper safety equipment. While it may be 'safe' when fully contained, the process containing it will pose a hazard to you and your team mates. While you may sneak it past an inspector at competition, I would recommend against it.
If this is for ballast or mass, there are other dense metals that will be nearly as effective without the safety concerns of lead such as stainless and standard steels and some copper alloys such as brass and bronze.
A free online resource for searching materials based on specific properties is
www.matls.com.