Linked Child Tracking

Is there a way to have a barrel on a vehicle track and fire at via mouse view?

Multiple ways, yes.

http://secondlife.com/badgeo/wakka.php?wakka=Vehicles
http://secondlife.com/badgeo/wakka.php?wakka=llMoveToTarget
http://secondlife.com/badgeo/wakka.php?wakka=llRotLookAt
http://secondlife.com/badgeo/wakka.php?wakka=llLookAt

Also, you can detect where someone is looking with Mouselook via a sensor and llDetectedRot.

err for thouse with no scripting knoledge please?

want it to track my mouse when sitting on the vehicle

Simply, do a sensor for the owner of the vehicle, or for whoever is driving it. Put the script into the cannon part. the script in pseudocode should:

set rotation to detected rotation * llGetRootRotation (or it is "/"?)
include a link message event so that when you take controls from the prim that takes controls, you can pass a link message to the firing prim.

Its pretty simple, and read up on the wiki too. If you havent done scripting before though, its going to be a pretty hard thing to accomplish without help

The simple version:

integer avatar = ""; // Avatar to track
default
{
    state_entry()
    {
         llSitTarget(<0,0,0.1>,<0,0,0,1>); // Non-zero target is needed to 
         // trigger llAvatarOnSitTarget();
    }

    changed(integer change)
    {
         if(change & CHANGED_LINK)
        {
             avatar = llAvatarOnSitTarget();
             if(avatar) llSensorRepeat("",avatar,AGENT,10,TWO_PI,0.3);
             else llSensorRemove();
        }
    }

    sensor(integer total_number)
    {
         // Note this may need "/ llGetRootRotation()" instead, or none at all.
         // I'm writing this out-of-world.
         llSetLocalRot(llDetectedRot(0) * llGetRootRotation());
    }    

    no_sensor()
    {
         // An error occured. Stop the sensor.
         llSensorRemove();
    }
}

Re, Imho: No controls need be taken for this operation. Yet.

Dont guess ya can make that script/s for me can ya

Addendum: For the record, we (the locals on this forum) are here to teach how these things work, TX. We're not here to create every script for you.

While I may be one of the few exceptions on "providing for free," we assume you will take this and go on to try to write the rest yourself. As such, this is a starter.

Thank you Jeffrey Gomez
I will have to test this later tonight after work.
And yes I do thank every scripter out there who has helped me with scripts sofar
I do try and learn from these and I have made modifycatons to sum in the past to add features that I learned to add
I just havent learned how to build one from the ground up yet
but I am slowly learning... and no I am not profiting off these scripts.
Most of these I request are things eather I use every day or the public can use
that and sum for self defence but thats a diffrent story... Friggen Mafia think they can controll the sandboxs and push me arround