The +Bow (PlusBow) Rev.2

Main Project Aim: Develop a homemade version of the Crossbow that has performance comparable to one modified to level 4. Due to increasing rarity and cost of obtaining them in decent condition, I will be making full construction plans available.

Secondary Project Aim: Include a rail attachment system to allow integrations to be mounted on the gun using adapter brackets and quick-release pins making the base weapon adaptable to the needs of different play types. Also work to reduce part count, simplify construction, reduce build cost, and make the +Bow as easy to service and repair as possible. The +Bow can easily and quickly be broken down into 3 or 4 subassemblies for shipping or transportation to wars.

Length: 36 inches (with 12-inch barrel attached)
Weight: 2lb
Plunger load: 18-32lb
Spring load maximum: 38lb
Optimal Barrel Length: 12 inches

Plunger rod has three notches affording different load rates which gives the user different range options.

Distances averaged
28lb Pull: 140 feet
22lb Pull: 110 feet
16lb Pull: 80 feet

Individual results will be dependent upon too many factors to list so take these only at face value.

Accuracy has been extremely good using only the iron sight designed into the rear frame piece.
I've been able to hit moving targets from 80 feet away without too much difficulty.
However it does help that I also have very accuract darts.

Nerfhaven Forum Thread

Video on Youtube

If you have any question you can contact me through:


Essential Tools
+ A Scroll Saw or both a Band Saw and a Jig Saw
+ PowerDrill or Drillpress
+ 1/2" & 9/16" flat-blade wood-boring drill bits (a.k.a. "spade bits") + Mitre Box & Mitre Saw or a power tool useful for cutting plastic rod or tube (such as a table saw, circular saw, or band saw)
+ #6-32 Tapping Bit
+ Screwdriver
+ Pliers or Wrench
+ Hobby Knife (to clean the edges of the sheets once cut)
+ Scissors
+ Inkjet printer
+ Packet of full-sheet label paper
+ Aluminum tape

Make the process easier
+ Table Saw
+ Band Saw
+ Scroll Saw
+ Drillpress
+ Sandpaper or Sanding Sponge

No other tools expressly needed. All tools listed are not easily substitutable. You can cut out the parts using a Scroll Saw, but a Jig Saw could be used to make the internal cuts and a Band Saw could be used to make the external cuts.

Part List
Download: plusbow2_partlist.txt

All items available through

Simply search for the part #s listed. Total cost of supplies listed is around $80 plus shipping. You will have enough excess of most materials to make atleast 2 or 3 more guns.

Step One

Download the cuttings template sheets: plusbow2_templates.doc (255kb)

Print them on full sheet label paper. If you ran out of color ink (like I did) make sure to use a colored pencil to mark the holes with the size you will need to drill them to based on the included legend.

Cut all of the individual templates apart using scissors. Set aside the template with the word "FRONT" on it.

Arainge the cutting templates on the thicknesses of polycarbonate sheet indicated on each template. It's quite easy to fit all of the needed parts onto each 12"x 12" sheet of polycarbonate.

Keep enough of a gap between the templates to allow the blade of the scrollsaw to cut inbetween the parts. Once you have them arrainged, remove their backing paper and apply them to the protective film on the sheets.

Step Two

Using a drillpress or power drill follow the color legend you printed or wrote on the labels to drill out all of the holes to the required sizes.

Also make sure to drill 5/32" diameter pilot holes in the center of the areas you will have cut out. Such as the pass-through holes in the frame pieces and catch plate, The slide tracks in the trigger and catch plate, the trigger wells in the sides of the grip, the center of the priming handle, and the optional decorative "+" signs on the body sides

Step Three

Use a scroll saw or jig saw to make the internal cut outs in the trigger catch and grip pieces before cutting them off of the rest of the sheet (unlike what's pictured). Start by feeding the blade through the pilot hole you drilled in Step Two then retensioning the blade.

Step Four

Use a scroll saw or band saw to make all of the external cuts needed to free and shape all of the parts out of the sheet.

Step Five

Use a scroll saw or band saw or hobby knife to round the corners on the trigger catch as shown. This will allow the trigger spring to fit over this peg.

Step Six

Using the side plates that they will eventually screw into as a guide, mark the edges of both sides of the frame pieces as shown.

Step Seven

Using a 7/64" bit in a drillpress or power drill drill to a depth of around 1/2 of an inch. Then tap the holes with a UNC #6-32 tapping bit.

Step Eight

Using a mitre saw with box, table saw, band saw, scroll saw or circular saw cut two 11-1/4" length sections, one 12" length section, and one 13" length section off of the 1/2" diameter plastic rod.

Mark the center of both ends of all of the rods.

Using a 7/64" bit in a drillpress or power drill drill to a depth of around 1/2 of an inch. Then tap the holes with a UNC #6-32 tapping bit.

Step Nine

Remove the cutting templates and protective film from the plastic sheet parts.

Deburr the edges of all of the sheets using a hobby knife To quickly remove the burrs simply orient the blade perpendicular against the edges of the sheet and run it along them. Any trouble spots and be cleaned with the hobby knife by manually cutting away the burrs.
Further smoothing can be done with sandpaper if desired. I would recommend doing so on the grip.

Step Ten

All of the holes that were drilled to 7/64" need to be threaded using a UNC #6-32 tapping bit.

Step Eleven

Assemble the center frame piece and catch plate together as shown using washers and 3/4" length screws.

Attach the 12" length section of 1/2" diameter rod to the center frame piece using a 3/8" length screw. Mark on it where the centerline of the catch plate is.

Remove the 12" rod and using a 7/64" bit in a drillpress or power drill drill through where marked. Then tap the hole with a UNC #6-32 tapping bit.

Attach the 12" length rod to the rear frame piece again using a 3/8" length screw. Install a set screw into the newly tapped hole by hand.

Install a 1" length spring (one with a load between one and five pounds) onto the catch plate and the set screw.

Step Twelve

Attach the 11-1/4" length sections of 1/2" diamter rod to the rear frame piece. Slide the rear frame piece onto the 12" length rod.

Step Thirteen

Attach the side panels using 3/8" length screws.

Step Fourteen

Follow the photograph labels for attaching the hardware to one of the grip pieces. You can use one or two 3/8" spacers for each grip half depending on how rigidly you want it to be attached.

Step Fifteen

Add a 3/8" spacer to the opposite grip piece mirroring the previous ones. Put a washer and a lock nut on the end of the 1-1/4" length screw, but only tighten them enough for it to lock or the trigger won't slide.

Step Sixteen

Use the assembled grip as a template to mark the edges on both sides of the rear frame piece where shown.

Using a 7/64" bit in a drillpress or power drill drill where marked to a depth of around 1/2 of an inch. Then tap the hole with a UNC #6-32 tapping bit.

Step Seventeen

Now use 3/8" length screws to attach the grip assembly to the catch and stock assembly.

Step Eighteen

Attach the forward side frames as shown.

Step Nineteen

Install the plunger cross and slide the plunger tube over it.

Step Twenty

Mark where shown on both sides of the plunger tube. Using a 5/32" bit in a drillpress or power drill drill where marked on both sides.

Step Twenty One

Insert the hex bushing adapter into the end of the plunger tube temporarily and mark it as shown on both sides.

You don't want to drill the holes in the hex bushing too far forward or it will prevent you from installing a barrel.

Using a 9/64" bit in a drillpress or power drill drill where marked on both sides of the hex bushing.

Wrap the hex bushing in 3 or 4 layers of aluminum tape or electrical tape then use a hobby knife or ice pick to poke through to where the drilled holes are in the bushing. Push it into the end of the plunger tube and line up both holes. Lightly hammer then hand screw the bolt all of the way through and affix it on the other side using a lock nut.

DO NOT OVERTIGHTEN THE HEX NUT AND SCREW. These do not need to be on extra tight. If they are they will distort the shape of the end of the plunger tube.

If you later have problems with the aluminum tape on the seam between the plunger tube and the bushing ballooning out over time, tightly wrap a rubber band around the aluminum tape on the bushing.

Step Twenty Two

Wrap the remaining cutting template around the plunger rod with the "FRONT" label pointing at one end. Try to apply this template as straight as possible.

Step Twenty Three

Using a mitre saw with box, band saw, or scroll saw cut the notches out by following the template.

When finished, remove the template and clean the burrs from the edges using a hobby knife

Step Twenty Four

Attach the plunger head parts onto the plunger rod as shown using a 3/4" length screw.

Step Twenty Five

Detach the plunger tube assembly from the rest of the blaster and spray a very generous amount of silicone lubricant into it. Then spray a light coat onto the plunger head itself.

It's the only lubricant that won't eat away or degrade plastics.

Step Twenty Six

Slide the plunger and spring into the plunger tube aseembly and slide it back into place while hlding down the trigger to allow the plunger rod to pass through the catch and frame.

Reattach the plunger assembly to the rest of the blaster.

Tie a rubber band to the standoff and the trigger as shown.

Make sure the align the notches on the plunger rod so that they are facing the top of the blaster.

Step Twenty Seven

Attach two 1-1/2" length standoffs to one of the plunger priming handle pieces using 3/8" length screws. Then attach the plunger priming handle piece to the plunger rod using a 3/8" length screw.

Step Twenty Eight

Prime the plunger to the first notch using the handle.
Loosen the screw on the priming handle piece that secures it to the plunger rod.

Rotate the plunger rod while pushing down on the top of the trigger catch plate to make sure the catch plate is sitting squarely in the notch on the plunger rod.
Make sure the priming handle is aligned with the stock rods.
Retighten the screw on the priming handle piece that secures it to the plunger rod.

Step Twenty Nine

Using 3/8" length screws attach the other plunger priming handle piece and the butt stock


Add your preferred barrel, and your +Bow is now complete. The process has taken anywhere from 4 to 9 hours from start to finish depending on the tools you were using.

Final Notes:
+ This gun is extremely durable, but in the rare event something does break it's not at all difficult to replace any of the parts.
+ This gun doens't involve any glue. Hot, cold, or otherwise. So it should be able to take heat, cold, or humidity without any problems.
+ The rubber band on the trigger isn't a vital part and the gun will still function if it were to break. It's only there to improve the feel of the trigger and could just as well be replaced with a short/weak extension spring. I didn't have any on hand.