Introduction: Fallout 3 Dart Gun Inspired Sling Shot

I have always been a big fan of the Fallout games, well to be specific: Fallout 3, New Vegas and 4. One of my favorite components of the game series is crafting. A standout iconic crafting item to the series is the dart gun from Fallout 3, a pistol grip crossbow that shoots poison dipped darts to cripple your enemies and the mutant creatures that roam the earth post a nuclear war. It consists of the following items combined to form a dart gun according to the schematic you find in the game:

-paint gun

-toy car

-surgical tubing

-radscoripion poison gland

All this being said I don't have a use for a poison dart gun (not sure what sane person would), but I do like the styling with the retro toy car and the idea of reusing items to make something useful. I also have a dog named Bunk (a small version of the dog companion Dogmeat) who loves to fetch orange ChuckIt balls. So combining these two things I made an instructable here to detailing the creation of a Fallout 3 Dart Gun inspired sling shot gun. This sling shot gun shoots small 2 inch diameter ChuckIt balls for your furry companion to retrieve.

Arguably not very useful but pretty fun to use.

Safety Note:

Don't aim this directly at friends or pets or other living creatures especially if you are loading this with something other than rubber pet or tennis balls.

Step 1: Collect Tools and Materials

Unlike the simple four component list from the game you will need the following to build the Fallout 3 Dart Gun Inspired Sling Shot:


Gun Frame

-Caulking gun (make sure that when the plunger of the gun is all the way to the front that the ratchet still moves forward when you pull the trigger otherwise it won't work for this, I used this one:

-Wood siding: 2 planks 2-1/2" Wide 3/4" Thick or a single 2x4 that can run the length of the caulking gun (minimum 8-13/16" Long)

-8 x 3/8"-16 bolts 2-1/2" long*

-7 x 3/8"-16 nut*

-8 x 3/8" washer*

-Cosmetics: wood stain and wood sealant

-1/4"-20 stud 2-3/4" Long*

-2 x 1/4"-20 bolts 1-1/2" Long*

-5 x 1/4"-20 nut*

-2 x 1/4" Washers*

-JB Weld

-4" Long 3/8" Spring

-2 x Brackets with 2 x 1/4" diameter mounting holes

-2 x Zip-ties

-4 x Elastics strands 5" long or rubber bands to hold extra ammunition

-Optional: Something to use as a stock, I used the handle of a old snow shovel

Toy Car

-Wood 2x4 about 19" long

-2 x 3/8"-16 Bolt 6" Long, or whatever you have around to support slingshot / act as uprights*

-4 x Wheels (Reused caster wheels)

-10 x 3/8"-16 nut*

-10 x 3/8" Washer*


-Wire frame bracket or something to use as foot hold with wood screws to attach it to the car

-2 x Deck screws 3-1/2" Long

-Alternatives to Toy Car: Skateboard, Retro/non inline roller skate, anything with two axles to support tight latex tubing and can be attached to the caulking gun


-Leather or sling fabric

-2 x zip-ties

-Small length of parachute cord, 6" long

-Latex tubing at least 3ft long, I used 1/2"OD 3/8"ID

*Note: You don't have to use these fasteners, I just used what I had laying around that felt sturdy enough to work


-Drill (drill press is helpful but optional)

-Hacksaw or Dremel with cutting wheel (faster option)

-Saw or Chopsaw (faster option)

-Sandpaper or Belt Sander (faster option)





-2" Hole Saw


-Sharp scissors or tin snips

-Philips screwdriver

Step 2: Wood Siding Part 1: Cut to Size

Wood Siding Description:

The purpose of the wood siding is both cosmetic and functional. It covers up the exposed metal plunger in the center and provides material for you to attach the toy car to with deck screws later on.

I used a two wood plank method, however, alternatively you could use a single piece of wood and place it in the center of the wire frame instead of on either side. If you did the single piece wood method you would pull back the plunger and then ratchet it on top of the wood creating a hard stop. The advantage of the single piece wood method would be that you can use the plunger axle as a gun stock. However, I thought the two strip method looked better and it also gave me access to the center of the frame to have some modularity options later on.

Anyways part 1:

1. Get your caulking gun and measure the opening distance between the where the solid part of the frame ends and where the plunger ends. The goal is to press in 2 planks of wood into the frame opening.

2. Cut your wood planks slightly longer than what you measure using a chop saw / miter saw or alternatively a hand saw with a miter box, you want to make sure you have a straight cross cut. Mine were cut to 8-13/16" long

You want the fit to be tight when pressing the wood into the caulk gun wire frame.

3. Test the fit, cut again if too large or sand slightly to get that tight fit.

Step 3: Wood Siding Part 2: Drill Holes for Connectors

In this step you will drill the holes through your wood siding planks that will be used later to bolt the 2 planks together around the caulking gun wire frame

1. First mark out the holes with a pencil, measuring instrument and straight edge. I put my holes 3/4" inwards from the plank perimeter with pairs at the center and 1-1/2" in from either end. Now I have marked out 6 holes, but I found that 3 holes with 3 x 3/8" bolts connecting the planks was plenty strong. I would make at least 3.

2. With the holes marked use a hammer and center punch to make indentions at the center of each hole marker. This will prevent your drill bit from traveling.

3. Get two clamps and fix your planks together, make sure they line up, there is no undo for drilling holes in the wrong place. By clamping the planks together you will ensure that the connecting holes line up to each other and it also means you only have to drill half as many holes.

4. Use a drill press or hand drill to drill through the planks at the hole markers. Start with a small diameter drill bit ( I started with 1/8") then increase the diameter up to slightly past your fastener OD. So if you are using 3/8" bolts like me then you will want to drill with a 25/64" or with whatever you have that is slightly larger. You want a loose enough fit so you push the bolts through from one plank to the other.

Step 4: Wood Siding Part 3: Ball Holders (Ammo Holder)

A nice way to use the additional wood material that it is not holding the toy car is to cut holes to hold additional ammo (fetching balls). This is completely optional, but it is always good to have extra balls in case your at the dog park and the ball flies over the fence.

1. Get your wood siding planks and remove the clamps.

2. Mark the centers between the center mounting holes and side mounting holes.

3. Use a hammer and center punch to indent the hole marker.

4. Get a hole saw with a diameter equal to the diameter of your fetching ball of choice. My dog is small so he fetches small balls, approximately 2" diameter, so I used a 2" hole saw. Drill out the pair of holes with the hole saw and hand drill.

Step 5: Wood Siding Part 5: Make It Pretty

Get your wood planks and wood stain of choice, I went with a dark roast color wipe on stain. You will also need a stirring stick and rag.

1. Stir the stain and mix until it is fully blended.

2. Dip the rag into the stain can.

3. Wipe on the stain until planks are fully covered, wearing gloves helps.

4. Let it dry.

Step 6: Toy Car Fabrication Part 1: Sketch It, Mark It

Toy Car Description:

The purpose of the toy car is to support the elastic latex tubing, to provide fixed points or anchor uprights as you pull the tubing back. I spent a lot of time at yard sales this summer looking for something like the blue racing car from the Fallout 3 game to use but didn't have any luck. So I thought I would just make one figuring that a homemade wood racing car is in the spirit of the game and a world before every kid toy was plastic.

Alternatively I was thinking you could use a skateboard or roller skate where you would use the trucks / axles as the uprights for the sling shot.

Part 1:

1. Get your 2x4, I used a 18" long piece.

2. Sketch out the outline of the car profile including a rectangular cockpit profile at the center of the car.

3. Measure out and mark the hole locations for the wheel axles. Then use a hammer and center punch to indent the holes. The wider the distance the more power you can create over a shorter pull back distance for the tubing.

4. Mark and indent the corners of the cockpit.

Step 7: Toy Car Fabrication Part 2: Hole Making

Using a hand drill or drill press drill out holes for the axles. Like before for the wood siding I stepped up the diameter from 1/8" to 25/64" to fit the 3/8" bolt to use as the axles.

Step 8: Toy Car Fabrication Part 3: Cut the Perimeter

1. Drill the holes at the corners of the cockpit.

2. Get a manual jigsaw and insert the blade through one of the corner holes at the cockpit. Then cut horizontally to the other corner hole.

3. Use a hand saw or electric jigsaw to make 2 vertical cuts to the cockpit creating a rectangular cut out in your 2x4. The cockpit will be used later to connect the toy car to the caulking gun and to mount the foot hold.

4. Clamp the 2x4 to the table or within a vice. Use your electric jigsaw to cut along the car profile you drew.

Alternatively you could use a handsaw but the electric jigsaw or a bandsaw will greatly speed this up for you.

Step 9: Toy Car Fabrication Part 4: Sand It

Sand the 2x4 down by hand or with a belt sander until smooth enough to paint.

Step 10: Toy Car Fabrication Part 5: Wheel Harvesting

I did not have any wheels for my car laying around so I took and reused caster wheels from an old ikea rolling shelf that I junked years ago. If you have some toy wheels or can think of something else go right ahead.

1. Push the pin / axle of the caster wheels outward to expose it beyond the bracket.

2. Use a hacksaw to cut the pin / axle then remove the cut pin and the wheel will be free.

3. Drill out the inner diameter of the wheel with hand drill or drill press to fit the axle size you are using. I am using 3/8" diameter bolts so I put a 25/64" hole into the center of my wheels.

Step 11: Toy Car Fabrication Part 6: Paint It

Paint your car or do whatever you want to make it pretty.

I kept it simple and painted it a royal blue like the car used in the game. Make sure you put a tarp or canvas cloth down before you make a mess. And check to make sure the wheels and axles are to your liking before you paint.

Step 12: Caulking Gun Modification Part 1: Trigger


The caulking gun is both your main support structure and trigger provider. Make sure when you are choosing the caulking gun that the plunger of the caulking gun when fully engaged to the end of the gun allows you to pull the trigger and have the mechanism return back from the spring sandwiched between the trigger and the frame.

The main benefit of using the caulking gun is that it has a nice frame for to you to build the sling shot around. The downside is the trigger is never locked. When you attach the latex tubing to the top of the trigger you need enough counteracting force from the spring to hold the trigger in position or else the trigger will move forward and release the ball prematurely. This is why you will see that I added an extra spring to the gun to increase the force keeping the trigger fixed. You need to make sure that the gun will only fire when you pull the trigger.

Alternatively you could reuse something else with a trigger. I used the caulking gun because I already had it and seemed like I could make it work. Maybe you could use a quick clamp or a paint gun like in the game. Ideally you would want something that stays fully locked until the trigger is pulled instead of the caulking gun where the trigger is unfixed and relies on you balancing counteracting forces.

Anyways Part 1:

You need to make a supporting structure to hold the slingshot pocket (the part that holds the ball) loop in place connected to the trigger.

1. The top part of the trigger for the caulking gun within the frame should be bent backwards providing a somewhat flat surface for you to modify. Mark and center punch the center of this flat surface of the trigger bracket. Drill a 1/4" hole into the center of this flat surface.

2. Acquire a 1/4"-20 threaded rod 2-3/4" long to insert into the 1/4" hole you made. If you find that your slingshot paracord loop at the end of the satchel tends to slip off this rod then use a Dremel or hack saw to cut the sides off the head of a 1/4"-20 bolt with a button head to create a threaded rod with essentially a hook on the end to provide a stronger hold on the loop.

Step 13: Caulking Gun Modification Part 2: Extra Spring Force


You will most likely need extra spring force so you can make a sling shot with sufficient firing power to be fun, without modifiying it mine would only shoot about five feet before the trigger would just be pulled forward by the tension I was putting on the trigger with the stretched latex tubing.

To increase the amount of spring force that pushes the trigger backwards you can either swap out the original spring with something stiffer or do what I did and add a spring to the bottom of the trigger handle. By adding it to the bottom of the trigger handle you will increase the amount of leverage from adding an extra spring. The further from the pivot point you put the second spring the stronger the force will be pushing the trigger back. Just make sure that it is a manageable amount of force, you need to be able pull the trigger still with your hand to fire.

Part 2 A, Extra Spring Trigger Handle Mounting:

1. Clamp the caulking gun in a somewhat vertical position so the trigger handle is accessible.

2. Mark about 3/4" up from the end of the handle at the center of the curved trigger handle.

3. If possible see center punch the center marker so your drill bit does not travel.

4. Drill out the center hole stepping up drill bits until you can fit your 3/8" bolt.

5. Test the fit and adjust as needed.

Alternatively you could JB Weld a long bolt onto the trigger handle or bolt on a bracket to move the spring even further down away from your hand / original trigger handle to increase your force even more and thereby increase your maximum firing force / potential energy limit.

Part 2 B, Extra Spring Forward Frame Mounting:

1. Mount your spring onto the trigger with your 3/8" bolt and nut plus two washers.

2. See how far you can stretch the spring towards the front of the gun then mark distance on the frame. This will be your forward mounting point.

3. Clamp the gun in a vice or on a table with bottom facing up.

4. Center punch the center of the mark you made on the frame.

5. Drill a 1/4" hole.

6. Mount your L bracket onto that single hole with a 1/4"-20 bolt and nut.

7. Mark the location of the second hole for the bracket using the bracket's existing hole as a guide, this will ensure that holes on the frame will line up with the holes on the bracket you are using.

8. Center punch and drill out this second hole location.

9. Mount the L bracket and the second L bracket in reverse orientation on top of it to check the fit using 2 x 1/4"-20 bolts, 2 x 1/4" washers and 2 x 1/4"-20 nuts.

10. Pull the spring forward and make sure you reach at least one of the verticals of the L bracket.

11. Adjust as needed to make it fit.

Step 14: Stock Fabrication Part 1: Find It and Cut It

Find something to use as a gun stock, an old yard tool works well. I used an old beat up snow shovel.

1. Put your calking gun next to the shovel and estimate about what looks like a good size for you and mark that point with a sharpie (I cut mine at 12-1/4" long).

2. Use a saw to cut it at the point you marked. I would recommend airing on the long side because you can always cut it shorter later.

Step 15: Stock Fabrication Part 2: Protect It

This part is optional. Most likely you will be using this slingshot outside and it will be exposed to the elements. I recommend you put on a protective wood coating to help the components last longer and it also provides that pretty wood shine.

1. Get yourself some rags, gloves and a container of your wood water seal of choice (I picked up some discontinued Thompson Water Seal at Home Depot).

2. Stir / mix your water seal thoroughly.

3. Pour some of the sealant onto your rag and wipe down you wood pieces: the previous wood siding planks and the stock.

4. Let it dry.

5. Repeat the coating process, you want at least 2-3 coats usually but refer to water / wood seal directions.

Step 16: Stock Fabrication Part 3: Add Mounting Features

1. Place caulking gun within the vice or clamp it down to a table.

2. Use a hacksaw or dremel with a cutting wheel to remove the curve portion of the hexagonal plunger rod at the rear of the caulking gun, cut it right where the curve starts in order to maximize the length that will be a part of the wood.

3. Bring your stock piece over to the caulking gun so you can get a feel for how much metal will need to be inserted into the end of the wooden stock. Then measure if you like but the mounting hole depth does not need to be precise, just needs to be deeper than the metal piece.

4. Measure the diameter of the hexagonal plunger rod across the diagonal, I measured slightly larger than 3/8".

5. Mount the snow shovel handle length onto the metal stub of the cut of plunger rod.

6. Check the fit and check the length with the stock pressed to the shoulder. If the stock is too long then cut it shorter and repeat the process.

Step 17: Sling Fabrication Part 1: the Pocket

Originally I tried to use a tennis ball to make a pocket to hold my projectiles (the small ChuckIt balls) but it didn't quite work. The tennis ball perfectly held the small ChuckIt ball but the tennis ball eventually came apart where the zip ties attached to the latex tubing. My second attempt using the traditional slingshot leather pocket worked much better.

1. Trace out a 4.75" x 2.5" rectangular region on the leather sheet.

2. Mark the centerline of the leather sheet along the horizontal.

3. Then mark the center of the center line and 3/4" from either end.

4. Use a cutting punch or an exact-o knife to cut holes at each of the marks you made.

5. Install zip ties at each of the holes you made on either end of the centerline / center hole.

6. Cut a 6" long length of paracord and press each end through the center of the leather patch. Then tie a knot on both sides of the leather pocket center hole so the loop never separates from the pocket

Step 18: Sling Fabrication Part 2: Attach the Tubing to the Pocket

1. String the latex tubing through each end of the zip ties on either end of the pocket.

2. Tie a knot so the length of latex tubing measures approximately 18" long folded / when the loop is folded to make 2 parallel strands.

3. Mount the pocket to test fit.

4. Snip the extra tubing length when you are satisfied with the fit.

Step 19: Assembly Part 1: Check the Fit

Before you put the slingshot together permanently assemble it together loosely to make sure everything works properly and fits.

1. Press the wood siding planks onto each side of the frame.

2. Bolt the planks together with the 3/8" bolts sandwiching the caulking gun in between.

3. Attach the spring from rear bolt on the trigger handle to a 3/8" bolt mounted with zip ties on the front bracket.

4. Insert the 3/8" bolt axles into the toy car and secure it with nuts leaving wheels on the bottom and exposed threads on top.

5. Use quick clamps to attach the toy car to the wood siding planks.

6. Put together the sling. I mocked up one with the latex tubing and a tennis ball I cut in half with zip ties tied to the sides of the tennis ball. Originally I thought the tennis ball would work well for the sling but the traditional leather works much better. In any case this is just to mock up the slingshot crossbow.

7. Mount the sling onto the slingshot by tying the ends tubing together in between the spring. Then pull the sling forward and wrap them around the axles. Then pull backward to attach the sling to the trigger threaded rod.

8. Check the fit of everything, make sure it feels sturdy, put it to your shoulder and pull the trigger.

Step 20: Assembly Part 2: Attach the Car

1. Get your foot holder bracket and place it against the cockpit. Then mark the location of the mounting holes. Centerpunch the marks.

2. Predrill the holes (pilot holes) for the mounting holes of the bracket.

3. Mark the centerline between the axles of the car.

4. Ratchet the plunger all the way to the front. Press in the wood siding planks to the caulking gun frame then install the 3/8" bolts to fasten the planks and frame together.

5. Line up the centerline of the car to the center of the caulking gun frame.

6. Clamp the toy car level and in center to the caulking gun frame. Make sure the clamp leaves one side open to drill into wood siding planks.

7. Ensure that toy car is in the correct location.

8. Predrill a hole/ make pilot hole to the right of the center of the cockpit into the center thickness of the wood siding planks.

9. Use a hand drill to drive in a deck screw into the predrill hole.

10. Repeat this process on the left side and make sure the toy car is level / perpendicular to the gun before you install the second deck screw.

Step 21: Assembly Part 3: Foot Grip

1. Place the foot hold bracket against the toy car.

2. Install the bracket fasteners: wood screw plus 2 washers.

3. Start driving in the wood screw by hand with the phillips screw driver then finish driving with the hand drill.

The foot hold will allow you to put your foot on the bracket while you draw the tubing back to load up the sling shot cross bow.

Step 22: Assembly Part 4: Bond the Front Bracket

Get JB Weld, a plastic stirring dish, stirring stick, a pair of gloves, the spring, 3/8" bolt, front bracket and a pair of zip ties.

1. Put the spring over the 3/8" bolt.

2. Squeeze in equal parts of JB welding into the plastic / disposable stirring dish / surface then stir and mix completely.

3. Applicate the JB weld to the 3/8" bolt along the length that will touch the bracket.

4. Zip tie the bolt to the bracket.

5. Put aside to cure for 15-24 hours.

Step 23: Assembly Part 5: Bond the Stock

Get JB Weld, a plastic stirring dish, stirring stick, a pair of gloves, the caulking gun frame, shovel gun stock and four clamps.

1. Squeeze in equal parts of JB welding into the plastic / disposable stirring dish / surface then stir and mix completely.

2. Applicate the JB weld to the metal plunger end.

3. Press the shovel gun stock over the plunger end.

4. Use clamps to secure the stock even with the frame by clamping the sides then use clamps to pull together lengthwise the shovel stock to the frame.

5. Set aside and let cure for 15-24 hours.

Step 24: Assembly Part 6: Attach Wheel Axles

1. Put a caster wheel onto the long 3/8" bolt then thread on a nut to secure the wheel.

2. Thread on a second nut and washer past the center of the threaded bolt.

3. Insert the axle into the toy car then thread on a second nut to secure the axle onto the toy car.

4. Repeat this process for second axle.

5. Add on the remaining wheels later if you so choose for appearance.

Step 25: Assembly Part 7: Ammo Strapping


You may need to add straps to keep the extra ammo within the ammo holders

Part 7

1. Install the remaining 3 bolts

2. Tie elastic strapping to form loops or use rubber bands which are already loops

3. Attach strapping in diagonal patterns to form an X over the center of each of the extra ammunition ball holders

4. Install nuts/washers over the strapping. I used flanged nuts here to save on washers / I had them laying around.

5. Test fit and adjust as needed.

*If you only made three holes then you can get away with a single strap loop placed across the ammo holder holes instead of the X pattern I made

Step 26: Assembly Part 8: Finish Extra Spring Assembly

1. Snip the zip tie extra lengths.

2. Attach the L brackets to the caulking gun frames using 2 x 1/4"-20 bolts, 2 x 1/4" washers and 2 x 1/4"-20 steps to the frame. You may need a pair of tweezers to help hole the bolt when you tighten the nut over the brackets.

Step 27: Assembly Part : Install the Sling

Load up the sling onto the gun.

1. Place the knotted end of the loop on the L bracket vertical closest to the center of the frame

2. Pull the sling forward and wrap each end around the axle above the top surface of the toy car

3. Pull back the extra spring and hook it onto the 3/8" bolt attached to the trigger

You are now ready to load and fire. I would add on the two remaining wheels now if you have them over the surgical tubing on the uprights.

Step 28: Conclusion: Fire and Play

Your Fallout 3 Dart Gun styled Sling Shot is now ready to use.

If you are satisfied with the position of all your components then I would go ahead and apply Loctite thread locker to all the threaded connections so nothing loosens up on you over time.

I hope this makes fetching with your dog even more fun, but this is even fun to shoot without a furry guy to bring the ball back for you.

Good luck building,


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