How to align weapon rotation

Align in hand weapon direction

If you align like this by default you will get a good result:

Item Aim Rotation Center Align

Is an essential component to assist with hand position and rotation during Fire Mode, it is automatically created in the JU Character Controller setup.

The Item Aim Rotation Center has the item wielding positions, and this will affect the direction of the weapon.

This rotation will not affect the trajectory of the bullet, adjust it so that the rotation is closer to aiming at the center of the camera. You may need to adjust the weapon rotation as well to get it to look good.

Aim Mode Align

If you want to use "Aim Mode" you will have to adjust the rotation of the weapon in this mode.

First, change your JU Character Controller's setting to "One Press To Aim" mode to adjust properly:

Place the Game and Scene windows side by side, press play and aim, press the Esc key and click on the weapon in the Hierarchy. Then just adjust the rotation so that the weapon's crosshairs align correctly with the center of the screen crosshair:

Note: if you are not seeing this green crosshair on the screen activate Gizmos

After aligning, just copy the rotation of the weapon, exit Play Mode and paste the rotation into Transform Component.