Thursday, April 30, 2009

Buzz Bee Tommy 20 Mod - Increase Rate-of-Fire!

As you all know, the new Buzz Bee Tommy 20 can now fire in full-auto mode! It does this via a motorised rotating drum magazine and dart pusher mechanism which automatically push foam darts forward in sequence into its 2 fly-wheels.

There are a total of 3 electric motors:
1 x Drum Rotator/Dart Pusher motor
2 x Fly-Wheel motors

As the speed of its motors are voltage dependent, increasing the voltage feed should be able to yield quicker drum magazine rotation and dart pushing, resulting in increased rate-of-fire (RoF).

In addition, the faster spinning of its fly-wheels should also "throw" the foam darts out at a higher velocity, thereby possibly increasing the firing distance.

Here is how i tested it with some simple components:

Step 1: Get the following items from an electrical supply store.
(Nerf Vulcan modders should be familiar with such items by now!)

1 x Battery Holder (holds 8 x AA Batteries)
1 x Battery Holder Snap-on Adapter
2 x Insulated Wire Leads (Red + Black w/ Crocodile Clips)

Step 2:
Attach everything together and install the AA Batteries (in this example, i used 8 x 1.5V AA Batteries which provide 12 Volt power in total). Once again, please take note of the Positive (Red) and Negative (Black) wire leads, do not let them short-circuit!

Final Step: Remove the Buzz Bee Tommy 20's battery cover and clip the Red and Black wire leads onto the connection points (clip properly and note the wire lead colours!).

Okay, time to test it out!

Here are the Test Fire Videos of my stock vs. upgraded Buzz Bee Tommy 20s:

Buzz Bee Tommy 20 RoF - Stock 4.5 Volt Power

Buzz Bee Tommy 20 RoF - Upgraded 12 Volt Power

The stock unit had a RoF of approx. 2 rounds per second, while the upgrade unit generated a RoF of approx. 3 rounds per second. Therefore there was a 50% increase in RoF.

In the upgraded unit, the foam darts also got "thrown" out of the 2 fly-wheels at a higher velocity too, with an average increased firing distance of around 6-7 feet.

If you are confident, you can try increasing the voltage further to increase the RoF and range even more, or use other power sources such as rechargable RC car li-po batteries to do the upgrade.

Just be careful not to burn out your blaster's motors! :)

An additional note for those of you looking to get into more detail in the modding of the new Tommy 20:

The front 2 motors powering the fly-wheels are seperated from the main body unit by a pair of electrical contacts (you can see them when you flip up the front barrel unit), therefore with additional mods, it is possible to power the drum magazine/dart pusher motor and the fly-wheel motors seperately with different power sources and voltages.

Hope we can see more mods done on the new Tommy 20! :)


  1. i cut part of my tommy buzz bee so it worked with nerf darts it was cool after that. the voltage just kind of makes you run out of ammo to fast

  2. Can you mod this gun to go further?

  3. Since the Tommy 20 is a fly-wheel powered blaster, the main method to increase range is simply by getting the 2 motors to spin faster (either increasing voltage and/or changing to higher speed motors).

    Be careful not to overheat the motors though. :)

  4. I used two 9v batteries to individually power the fly wheels and the magazine. I've dry-fired consistently for 5 minutes and nothing happened. These guns are very reliable.

  5. i removed the fly wheel motor and replaced them with ones from rc helicopters and then took my video camera battery for the front and for the back did the mod demonstrated here

  6. I tried this with 9.6 volt battery. It jams because the darts aren't push forward into the flywheel. Do you have any suggestions? I have a first generation Tommy 20, so maybe that's the problem. It still works, however, with 4.5 volts.

  7. WillBill,

    Well, i don't have a first-generation Tommy 20, so i can't really comment on that.

    Perhaps the first-generation Tommy 20 that you have tends to have issues when there is faster motor speed from higher battery voltage.

    Guess you'll just have to tinker with it to troubleshoot further.

  8. Is there a way to make the front motors better attached the power source so as to prevent the power cutting off from the gun shaking.

  9. k,

    Power should not be cut off during firing.

    Perhaps your unit has some loose electrical contacts between the main unit and the front unit? Just check and see if you can make them more secure.

  10. Do you know if a full barrel/turret removal mod would work on this gun? It mould make reloading mch faster to just put a nother turret in!

  11. sirhazza,

    Its possible, just requires some additional modding work... and more Tommy 20 sets to "donate" their turrets for such a project.

  12. I tried doing this with my Tommy20 using 8x 1.5V AA batteries. Almost cooked the thing. The ROF was FAR FAR higher than his 3/sec. Scary. The fly-wheels feel like they're about to fall out at that voltage. I tried it with a 9V battery as well. Same result. Almost cooked the thing.

  13. {obrigado} anks for the tip. was difficult to find your site ...
    another technique known to leave more quickly, using batteries?

  14. willian,

    Yes, you can use more batteries to increase the voltage, which would increase the motor speed to help propel the foam darts further.

  15. i just bought one at walmart yesterday, how do you tell the generations apart?

    wont the 12volts burn the motors?

    i tried using this gun with stephans(darts) and its works horribly, any tips on that?

  16. Gabriel,

    The earlier yellow versions were semi-auto while the newer green versions are full-auto.

    12V seems to work okay, but i've not tested them extensively to determine how long the motors can last with that voltage though.

    You'll need to increase the thickness of the flywheels to narrow the gap between the them, so that they can grip and propel the foam darts (ie. stefans) with narrow tips better.

  17. I've tried this mod with 9v batteries and my clip stopped rotating and just started clicking as if it were trying to turn but couldn't, but will work as normal on 4.5v. Also some darts fly out sideways of the barrel. Any ideas??

  18. willowcheese,

    Perhaps the 9V batteries you used happen to be abit low on power? 'cos 9V alkaline batteries have very low mAh capacity so they tend to run out of power very quickly.

    Foam darts flying out sideways in Tommy 20s is a common issue, this is due to its horizontally positioned dual-flywheel design. If one of the flywheels is spinning just slightly slower than the other, or if the foam dart tips are not straight, then the foam darts would tend to get propelled at odd angles.

  19. how do you connect the positive clip to the positive in the battery box?

  20. anthony,

    Just clip it onto the + contact plate.

  21. Will the same volt mod work for this gun that you did for the nerf barricade?

  22. Could you do the same TrustFire voltage mod on the Auto Tommy 20 as you do on the Nerf Barricade?

  23. Troy and Dieyuppiescum91,

    Yes, the voltage mod can also work on the Tommy 20.

  24. i put a 9 volt in mine and now it sends almost all of the power to the one motor the wires are directly conected to it and hardly any to the other one...What should i do?

  25. jlama,

    Not too sure why you experience that effect, perhaps your unit's circuit needs to be re-wired or something.

  26. Does anyone know the wire gauge used in the gun?

  27. I...don't like 'buzzbee'.D:

  28. because of yellow circular electrical devices directly off the battery case on the interior, more voltage will occasionaly mean less per formance, and I personaly have had this problem.

  29. Are we able to just put TrustFires in them?

  30. So I tried this with my tommy and the barrel spins super fast but the darts dont shoot... only the first dart shoots and there is a clear smell.... i literally used the exact same parts, any ideas?