Need Help with first person shoting game(shoots)

Hi guys, i am new in creation games, but for now i know some bluprint stuff, and want to test my self by try do my shooter game demo with guns and shots, but i’m don’t know what better to use for bullets --projectiles or single line traces? i think for grenades and rocket launchers and other slow rate weapons i need better use projectiles(and in this projectile BP i can create all damage VFX, logic, and other)but if i have fast rate weapon, is normal for spawn hundreds of projectiles(bullets), or for this stuff all developers using raycast(single line trace), or something else?

Also try to ask about animation, for example in official first person shooter game demo all hand animations without weapon(only hands), maybe better create animation with hands and weapon like a single animation file?

Sorry for bad English