[ Oda asking Bean about modern weaponry might be biting off more than he can chew, but... Bean sees no real reason not to indulge him. This whole situation is impossible, and while he's not sure he believes Oda about not being able to change history with the information, it's less about him bringing the intel back with him, and more about Bean not believing that it's even possible for him to go back at all. ]

Guns of one form or another have taken over most all modern warfare. No army relies on bladed weapons anymore. Guns come with either projectile or energy-based ammunition. Street level enforcers use magnetic whips for close quarters combat.

[ He won't tell Oda about the Little Doctor. No need to blow his tiny mind with a weapon that can take matter apart at a molecular level. ]