The first step to modding your Hyperfire is to open it up. There are 16 screws holding it together; 14 in the shell and 2 in the priming slide. All of the body screws are identical and the two in the priming slide are both unique. When you remove all the screws and open the shell, you should see this:
From Left to Right: Priming slide screw #1, Body Screw, Priming slide screw #2
This mod guide will cover removing the ARs and upgrading the spring. Set your tactical rail attachment aside and remove the turret. Unscrew the 5 screws from the back of the turret; they should look like this:
Open your turret and remove everything. Separate everything into two piles like so:
Dart Pegs on the left, Springs and ARs on the right
You only need the dart pegs on the left. Using a dremel, hobby knife, w/e, remove the center of each dart peg, like so. Make sure to keep the outside ring intact. You may wish to skip this step if you intend to only use stock darts.
Right: Before, Left: After
Place all the altered dart pegs back onto the turret barrels. Your turret is now done and ready to go back together.
To add a spring, remove the plunger assembly from the shell and slide out the plunger rod. You can slip the catch off the back to add another spring. I added what I believe is a barrel return spring for the Pistol Splat, but you can use whatever works for you. With this setup, I did not need to upgrade my catch.
Put everything back in the shell; it should look identical to the first picture. Screw everything back together and your done.
I saw no consistent range increases with stock darts, although I did eliminate the blaster's tendency to try and eject the darts beforehand. For an explanation, watch the video. With Stephans, I'm seeing ranges of 45-50'., which is a nice increase from the 25-30' it shoots stock. I would not recommend modding this blaster for use unless you intend to replace the internals.