So first you take a peice of 1" pvc and cut it down to about 3-4" sand around the outsides of the pvc and sand around the inside of the orange stock titan rocket barrel. Then add the epoxy around the pvc and then slide it into the orange barrel. It should be a perfect fit, if it is not then keep sanding.
Then take this peice from the end of your 1/2" pvc pipe.

now cut about and inch or so off.
sand that little baby evenly around the outsides untill it can fit snugly inside the 1" pvc pipe. Sand down the inside so this pvc ring can slide over 1/2" pvc pipe with little friction.
Now add some epoxy and pop that into place inside the 1" PVC at the very front.
It should now look like this.

This creates perfect stability. The barrel doesnt wobble around and is perfectly straight all the time. Even with a 2' barrel It is straight. Just slide the barrel through the stability piping and pop it into the coupler and your good to go.
None of this would have been possible without Ompas Titan mod. Thanks mate!