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Defender T3 Modification

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#1 koree



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Posted 09 July 2009 - 11:25 PM

The potential of the Defender T3 arrow blaster has not been explored extensively in the nerf internet community. Usually, the underslung side arm of the DT3 set has been sought after as a secondary but the top gun has usually been salvaged for the use of its spring.The goal of this project is to use very simple tools and very basic techniques to turn the DT3 arrow blaster into a primary worthy stefan firing blaster. To accomplish this, this write-up will include upgrades to the length of the plunger draw, the firing mechanism, and adding a 1/2” pvc coupler. Through the process, there will be no cuts to the shell to maintain the aesthetic of this blaster. This write-up will not include modification of the DT3 sidearm, as this has been explored by the nerf community and a write up and a video are available on how to do this.

Necessary equipment

DT3 set, both arrow blaster and underslung sidearm
Electrical tape
Plastic safe lubricant
Pipe cutter or hacksaw

Spring for firing mechanism
Hot glue with hot glue gun
Torsion Spring

Opening the DT3

Remove the side arm and all the screws. Also, using a knife or any other thin and sturdy object, remove the arrow holder on the top of the blaster.

Posted Image
Opened view

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Plunger draw extension

When experimenting with the DT3 arrow shooter, one will notice that in it’s stock state, the arrow blaster shoots farther when shot without using the trigger mechanism (by removing the side arm and holding the “scope” handle) This is because by not using the firing mechanism, one can provide more oomf to the arrow by pulling the plunger farther back than where it catches. We can improve the length of the plunger draw by adding another spot on the plunger rode for it to catch. First, remove the plunger from the plunger tube.


Proceed to disassemble it until all pieces are separated. This can be simply done with a bit of finesse and light tugging.


Now, take writing utensil such as a sharpie and draw in a catch point an inch closer to where the plunger tube was.


Now, taking a sharp knife, carefully chisel away at it. This can also be done with a dremel or other power tools, but considering the rarity of this gun, it would be best to simply be careful and take your time. With a good knife, it should only take about 10 minutes.


If done correctly, this will increase the travel of your plunger rod during firing by one inch.

Improving the plunger seal.

Put your plunger rod back together including the spring. Now it is time to improve the seal of the plunger head.

Take your electrical tape and wind it around the plunger head.


You should stop when you feel you have a good seal that is not too tight when placed into the plunger tube. Once you are certain you have a good girth for the plunger head, take your plastic safe lubricant and apply it to on top of the electrical tape. It should look like this.


Improving the trigger mechanism

The stock DT3 firing mechanism for the arrow blaster is very finicky. This is mostly due to how the catch is dependent on the side arm for catching the plunger rod. To alleviate this issue, we can add a spring to the arrow blaster’s firing mechanism, allowing it to catch on it’s own but still allowing the side arm’s trigger pull to fire it. Take a spring a spring like this one:


Which came from


and cut off the top 3 turns and hot glue it to the firing mechanism like so:


Add a dab of hot glue to the other end of the spring and then put the mechanism in it’s place. This will make the plunger catch both on the stock and newly made catch point very securely.

Coupler Addition

First, reassemble the blaster. Now cut the barrel of the arrow launcher so that there is 1.25” left on the original barrel.


Now take a 1/2” pvc T like this one


And cut off two branches of it


Believe it or not, this will slide over the existing barrel and form a perfect seal. Leaving you with a place to place 1/2” pvc on the end of it.


Now place your favorite barrel on it and your done.


And there you have it, currently it’s pushing 80+ feet. Fortunately, this gun can be upgraded further. I’ll be doing a spring replacement in the near future. (Hopefully before the contest ends.) It should also be noted, that when adding a spring to the firing mechanism, it can be replaced with a torsion spring (home depot didn't have any), possibly even discarding the need for hot glue. Even with the small dabs of hot glue required, this blaster is able to perform very well with very few tools and simple modifications. The blasters are linked on the same trigger on different pull lengths which are very easy to distinguish, leaving the side arm as a great second or counter rush shot. The blaster's stock appearance has been maintained and is extremely comfortable to hold.

Thank you very much reading,

Questions, comments, and criticisms are very welcome.

Edited by koree, 09 July 2009 - 11:28 PM.

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#2 BustaDartInYOurAss



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Posted 09 July 2009 - 11:27 PM

A very simple and clean modification, I like it. Although I noticed one thing, doesent the Defender T3 arrow shooter and a Big Bad Bow plunger look remarkably similar.

EDIT: Sorry I though there were the same because I though I used a BBB plunger in my crossbow, turned out it was a Defender T3 plunger. So it turns out that the Crossbow and Defender T3 plungers are identical in diameter and legnth and where the walls are placed.

Edited by BustaDartInYOurAss, 10 July 2009 - 12:34 AM.

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#3 CoasterDynamix757



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Posted 09 July 2009 - 11:34 PM

Nice mod, but one question. Why did you butcher a tee coupler, when you could have used a regular 1/2 inch PVC coupler?

Edited by CoasterDynamix757, 09 July 2009 - 11:38 PM.

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#4 Blue



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Posted 09 July 2009 - 11:44 PM

Awesome. I was hoping someone would figure out a trigger that worked for the top gun.
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#5 wingd man

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Posted 09 July 2009 - 11:54 PM

A very simple and clean modification, I like it. Although I noticed one thing, doesent the Defender T3 arrow shooter and a Big Bad Bow plunger look remarkably similar.

Just another sealing mech. That's like saying that the longshot and nitefinder are similar or that the strike fire and maverick are similar; just another sealing mech.
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#6 taerKitty



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Posted 09 July 2009 - 11:58 PM

Wonderful - it's easy, clean and effective. Looks great on the categories they provided.
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#7 koree



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Posted 10 July 2009 - 12:05 AM

Nice mod, but one question. Why did you butcher a tee coupler, when you could have used a regular 1/2 inch PVC coupler?

The 1/2 pvc couplers I have do not fit over the stock barrel very well. The 1/2" T however slipped over my stock barrel without needing any glue at all and formed a perfect seal, therefore i went with that.

Thank you for the comments everyone.

Edited by koree, 10 July 2009 - 12:05 AM.

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#8 Mehku



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Posted 10 July 2009 - 12:10 AM

Impressive modification. I have had bad luck hot gluing springs in. They always fall out. Have you had any similar troubles with the trigger spring?
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#9 white moonlight

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Posted 10 July 2009 - 07:10 AM

Very nicely done.

I never knew that DT3's got that kind of range.

Also at the end you said the sidearms stock appearance has been maintained, when you say appearance do
you mean it has been modified, and if so what are the ranges?
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#10 Hi Yah

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Posted 10 July 2009 - 08:04 AM

Nice job. This is the first mod I've seen on the arrow shooter.
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The yellow balls are also slightly smaller in diameter than the green ones.

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