Preston Garvey's Deathstar laser....

I can't currently check this myself as I'm at a point in the Minuteman quest line where all Preston keeps doing is checking if I'm ready for the Castle, so I can't currently make him my companion.

I understand that if you have a Laser Musket with the Neverending legendary title you will in one shot fire off ALL your Fusion cell ammo.

Is it possible to give Preston a Neverending Laser Musket. If so, what happens......