trackOffset : Phaser.Point
The Track Offset is a Point object that allows you to specify a pixel offset that bullets usewhen launching from a tracked Sprite or Pointer. For example if you've got a bullet that is 2x2 pixelsin size, but you're tracking a Sprite that is 32x32, then you can set trackOffset.x = 16 to havethe bullet launched from the center of the Sprite.
Source code: plugins/weapon/WeaponPlugin.js (Line 360)