And, now I'm doing really tiny details. At this point I figured that this ship will take 2-3 weeks of work. In this tutorial I covered maybe 2 hours or so.

Now create turret. I made it from three objects. All shall be parented under base.

Change the pivot point, so gun will pivot nicely. (move tool, than press insert, move pivot, and press insert again)

Create locator object.

Select locator, and than select the base of the turret.

Go to animation mode and go to constraints/Aim. In my case base is aiming with -Z axis. So I put -1 in Z field.

Also base is pivoting only around Y axis.

Then select locator, and than the gun and do another Aim constraint. In this case change axis to Gun Pivoting axis. In my case it's X.

Set limits for gun rotation.

Now you have gun that's aiming to locator.

Go to dynamics mode and create particle emitter with default options. Move it to the gun's top.

Rotate it to match the rotation of the gun.

Set mode to directional and set axis to -Z (-1 for Z), also change the speed to 15 or more.

Select the locator and right click in channel box. Go to add attribute. Set the name to "Rate", and the type to float. Click Add.

This attribute will control the rate of gun's fire.

Go to connection editor, and on left side load locator, and on the right load emitter. Connect locator1.rate to emmiter1.rate

In particle shape attribute change render mode to streaks. These are hardware shaded particles so compositing is needed. If you want to use software particles change mode to Tubes, and lower the numbers for radius1 and 2. Note, if radius is smaller than 0.1 particles won't render so you might need to change scene scale. At this point I'm not very worried about particle shading.

To add color click color button.

You will get three new attributes. Change them to get color you desire.

So, the gun is ready for firing.

By using locator you can control multiple turrets with single locator. This will be very handy later...