Introduction: 25MM Pneumatic Sniper Rifle

Picture of 25MM Pneumatic Sniper Rifle
***Disclaimer*** The following is for informational purposes only, i take no responsibility for what you do with this knowledge. i can not be held responsible for any property or medical damages caused by this weapon. i would advise you to check your local laws. These types of guns are illegal in some areas, and i would highly advise you against building one of these in said areas. Pneumatic rifles can be very powerful and should never be pointed at a person or animal. Lastly when dealing with pneumatics never over pressurize them and always use NFS-PW pipe (as apposed to DWV)

well before we begin i must state a few things...

-PVC can only be used at half or less than half the pressure rating stamped on the pipe when pressurized gases are used in the pipe
-i would suggest never pressurizing this cannon above 150 psi, remember its only plastic
-never store any type of PVC pneumatic with pressure still in it
-always allow a full 24hours for PVC glue to dry before pressurizing
-when building pneumatics always use metal or PVC pipe (never ABS)
-PVC is shock sensitive meaning if its dropped on a hard its very likely it will be damaged and it would be very dangerous to pressurize after damaged
-PVC becomes very brittle below 32 degrees (Fahrenheit) and is very likely to explode if pressured in such conditions
-when building pneumatics pressure rated pipe should always be used (none of that cell core or DWV crap)
-the most important part of any pneumatic are the PVC welds AND I HIGHLY SUGGEST YOU READ THIS TUTORIAL before you even think about starting this.
-when you are dealing with high velocity projectiles always remember you safety glasses
-always be sure of your back stop when shooting any form of rifle, pistol, gun, bow.... anything that can fire some vague form of projectile
-and use common sense!
-do not use un-regulated HPA or CO2 in a PVC cannon ever they are stored at to high of pressures to be safe in PVC, but if you have a properly regulated setup they can be used ( if you lower the pressure to about 100psi)

Now onto the good part...

this is my entry for the launch it challenge, it is a 25MM Pneumatic Cannon. it has 2.5 foot long one inch diameter barrel with a custom bolt action mechinism, of course we have the 3-9X40 sniper scope, and a 1" modified sprinkler valve as the primary firing valve.

The Video...

invalid movie:

remember always wear safety goggles, you never know where or when something will ricochet especially when its traveling at 300+FPS

Fun Fact: PVC shards can't be picked up by X-Rays (this is a safety tip! don't rush or you'll get a PVC shard in you and you probably wont get it out. im not saying you should sneak one of these into your luggage and go threw airport security. it would be way to big any way)

better video coming soon

If you like this instructable please register and vote for it in the launch it challenge (by click the plus icon next to the title)


power source------------------compressed air
power source pressure-----100psi
chamber volume--------------45 ci (approx.)
barrel volume------------------25 ci (approx.)
c/b ratio--------------------------1.8 to 1(approx.)
firing valve----------------------pneumatically actuated sprinkler valve (a "modded sprinkler" valve)
pilot valve-----------------------blow gun valve
fill valve--------------------------female quick disconnect
fire rate--------------------------single shot, bolt action
caliber---------------------------25MM ( one inch)
projectile velocity-------------unknown (coming soon)
effective range----------------unknown (coming soon)
maximum range-------------unknown (coming soon)
optics---------------------------3-9X40MM rifle scope
primary material used------PVC pipe



Step 1: The Parts...

Picture of The Parts...

we will be making this particular pneumatic out of mostly PVC so it is relatively inexpensive to make. here is what your going to need.


( 1x ) 2" PVC cap
( 1x ) 2" PVC coupling
( 1x ) 2" to 1" PVC bushing
( 2x ) 1.5" PVC couplings
( 2x ) 1.5" to 1" PVC bushings
( 1x ) 1" PVC tee
( 2x ) 1" PVC 90 degree elbows
( 2x ) 1" PVC male threaded adapters
( 1x ) 1" to .75" bushing
( 1x ) .75" PVC cap
( 1x ) .75" PVC tee
( 3x ) .75" PVC 45 degree elbows
( 2x ) .75" PVC 90 degree elbows
( 1x ) female quick disconnect 1/4"
( 2x ) 3/8" by 1/4" compression fittings
( 1x ) blowgun valve
( 1x ) 1" sprinkler vlave
a few inches of 1/4" ID flexible tubbing
assorted bits of 2", 1.5", 1", and .75" pipe


a dremel
a band saw
a drill (preferably a drill press)
PVC primer (make sure its primer and not cleaner or it could end badly)
PVC glue

Step 2: The Chamber...

Picture of The Chamber...


The chamber in a pneumatic cannon is a buffer zone between the valve and the bike pump/ compressor. It allows a large amount of air to be stored and exhausted very quickly when fired.

this is my chamber, it is a 12 inch long piece of 2" PVC pipe with a 2" cap on one side and a 2" coupling on the other, attached to the 2" coupling is a 2" to 1" reducing bushing. After the chamber was glued i let it sit for an hour (so the glue could partially cure) then i drilled a 1/2" hole in the side of the 2" cap so i could thread in the brass quick disconnect. do not use any Teflon tape on this fitting, if it starts leaking put some epoxy putty or JB weld on the section where the threads meet the chamber.

Step 3: Gun Body...

Picture of Gun Body...

the gun body connect the chamber to the valve and all the other parts of the gun (trigger, stock, ect)

first cut a piece of PVC double the length of a 1" socket and glue it into one of the 1" PVC elbows. then insert a a long piece of 1" pipe into the 1" elbow and the 1" tee( but don't glue it) this will help you get the joint between the 1" elbow and 1" tee perfectly straight. now glue the short piece of pipe sticking out of the the 1" elbow into the base of the 1" tee, use the long pieces of pipe to make the joint as straight as possible or the barrel will be off to the left or right of the gun. next is a rather odd step listen closely, i want you to glue the outside of the 3/4" end cap into the the back of the 1" tee. there are two things you want to remember here not all end caps will work do a dry test before you glue it and this is the part where the stock is connected to the body so make sure you insert the cap the right way (so the socket part is facing outwards making it possible to insert a piece of 3/4" pipe). next cut 7" piece of 1" pipe and glue it into the remaining socket of the 1" cut a short piece of pipe and connect one of the male adapters to the remaining socket of the 1" Tee. the last piece your going to need a dremel for you need to modify one of the 1" 90 degree elbows to it can slid along a 1" piece of pipe relatively easy. sadly there is no trick to doing this your just going to need to take of a little material at a time until you get it just right. once the elbow has been modified glue the 1" to 3/4" reducing bushing into its unmodified socket then slide it onto the 7" long piece of pipe which is now glued in place. then glue the other side of the 7" long pipe to the chamber. you have now finished the body of the gun.

Step 4: The Stock and the Valve

Picture of The Stock and the Valve

now build the stock, you should be able to figure it out using the pictures, i don't have any specific length measures becuase i just kinda guessed. the stock is one of the few thing that do not need to be glued although it would be a good idea to do so. also you can use whatever design you want be creative find a combination that looks cool. in case you wonder this is what you needed the ( 1x ) .75" PVC tee,( 3x ) .75" PVC 45 degree elbows, ( 2x ) .75" PVC 90 degree elbows were for...

onto the valve, my valve is an orbit jar top that i have modded. normally it would be triggered by an electronic pulse but this does not allow the valve to open quickly so i modified to to run completely pneumatically , there are many tutorials on how to do this for example here is one here is another. if you cant figure out how to mod the valve i suppose you can buy one from here, i know the guy who runs that place hes not going to scam you and his work is very good quality. anyway to install a sprinkler valve on this particular cannon aply a good amount of Teflon tape to the 1" threaded adapter then remove the top of the valve and screw on the valve itself.then go ahead and put back on the top. do not put on the blowgun as of yet.

side note: be sure to put the sprinkler valve on the right way, becuase it will only work in one direction. there should be an arrow some where on it indication the direction of flow, remember the air is going to be flowing from the chamber to the barrel

Step 5: The Bolt and Barrel Assembly

Picture of The Bolt and Barrel Assembly

in this particular bolt assembly the barrel moves with the bolt which could cause accuracy problems if the bushing is not modified correctly. but anyway its a modified version of THIS. the first thing you need to do is attach a 14 inch long piece of 1.5", then use epoxy putty to attach it to a piece of wood. This will make it a lot easier to cut, then you need draw a box that is about 10 inches long (refer to the pictures if you are confused). this will be the line you cut along with the band saw after the box has been cut out you will need to cut off the last inch on each side where the epoxy was holding the pipe to the wood. after the excess has been cut off each side attach a 1.5" coupling to each side. next you will need to modify the 1.5" to 1" bushings so that a piece of pipe can be slide completely through them with relative ease. in a stock bushing there is a stopper at the end off the bushing that prevents pipe from going all the way through. this will need to be ground off with a dremel, you might also have to also slightly enlarge the 1" socket of the bushing also. after the bushing have been modified glue them into the 1.5" bushings. then take a1.5inch long piece of 1" PVC and glue it into the 1" male threaded adapter and insert it into one of the bushings (it doesn't matter which). then cut a small notch into one side off the end of the bolt assembly (this doesn't make much sense so just look at the picture)

now we must build the the actual bolt handle; it's one of the simpler pieces. it is a hose clamp with a hole drilled through it and a dowel held in place with a wood screw. it does take a bit a measuring and test fitting to get the hole in the right place, but its worth the time to get it right. after you have screwed the handle onto the clamp insert the barrel into the bushing then put the hose clamp on it loosely. now force the barrel as far back as it can go, you should notice that it can actually go into the other bushing and it is very important that it does. once this is complete, tighten the clamp onto the barrel very tightly.

note : you can make the barrel pretty much however long as you want it. mine was 2 and a half feet of 1" pipe

Step 6: Scope Mount and Other Add-ons

Picture of Scope Mount and Other Add-ons

in this step i will discuss the additional parts that are not necessarily required but add a nice touch. my biggest recommendation is paint it makes the cannon look so much better, it makes it look truly intimidating. if you do decide to paint it i would suggest using Krylon Fusion for plastic it gives a terrific finish. i went with ultra flat black but i bet a sweet camo paint job would look really nice on this. when you do paint i would suggest protecting the first 12inches of the barrel other wise the paint will make the bolt very hard to operate (found out the hard way so don't get any paint on it)

barrel supports are small pieces of wood (in most cases) cut to the profile of the pipe, they add stability to the launcher when fired and take a great deal of stress off the joints. i would highly recommend you make some for you own safety. i traced the outline of the pipes onto card board then transfered that to a piece of pine that was cut by my band saw to make mine.

next up is the scope, my particular scope was made for an airsoft gun (almost identical replicas of real guns ) and it used an RIS mounting system. this meant i needed a RIS rail to put on the body of the rifle. for me RIS rails are very common and easy to find becuase i happen to have about 10 semi working airsoft guns (i got them in trade for a piston valve). if you don't have any buy a crappy gun for $10-$20 off or a similar supplier. the RIS rail was attached to the gun using 2 hose clamps it took a bit off adjusting but eventually i could shoot the gun pretty accurately.

additional items to consider...

a "noise reducing barrel extension" *cough* silencer *cough* but if your caught with that your screwed and that is exactly why im not telling you how to make one.

a bi-pod, i have one from an AK support type gun but cant find a good way to mount it

laser sight, well it would only be useful at night

Step 7: Trigger Assemlby

Picture of Trigger Assemlby

the trigger assembly consists of only a few parts but ti requires heavy modification. the first step is modifying a short 4 inch long piece of 3/4" pipe. you need to cut two slots in it length wise so a blow gun valve can be inserted into it. it is rather hard to describe so just look at the pictures. the next part is the 3/4" 45 degree elbow, you need to make a hole in it so you can connect a hose to the blow gun. once again refer to the pictures of this piece also but before you cut the hole remember to glue in a short piece of PVC into th elbow. after the pieces have been modified connect the elbow up to the rest of the gun (using the 90 degree 1" elbow that was modified earlier) and hold in in place with a screw of some sorts (so the trigger doesn't twist to the side as your firing). once the elbow is secured on the gun feed the hose through the hole in it and connect up the blow gun valve. then your pretty much done, congratulation's you have a 25MM sniper capable of doing some serious damage

If you liked my instructable be sure to vote for it in the instructables launch it challenge


rikkebobbie007 (author)2017-03-28

Could I use black iron pipe?

jeven123 (author)2016-10-01

what is the video called? i could not get it to work.

luismuñoz (author)2015-12-13

man, that was amazing, can you send me the file by email please? i cant download cuz i need a Pro membership. LOBOPLATEADO3131@GMAIL.COM.

Depechemodian (author)2015-05-26

Hello, first of all, congratulations for this great work, is impressive. I would like to ask if you think you could give pressure with a hand pump for bicycles. Thank you.

mtempest1 (author)Depechemodian2015-08-26

I use a bike pump for mine and get to 100 psi easy.

mtempest1 (author)Depechemodian2015-08-26

I use a bike pump for mine and get to 100 psi easily.

EpicMinecrafter870 (author)2015-08-22

One small step for man one giant leap for homemade nerd weaponry.

dannuer (author)2015-05-31

Hello I would like constuir this rifle but do not understand much because my language is Spanish and some material names I get distorted in the translator , if possible please thank me send everything about the respect to my mail as I do not have I could not download the pdf of this good stuff, as this page will not let me thank you for your collaboration , greetings from Venezuela

BronsonA (author)2015-05-13

I got fined 50$ for just walking around and shooting it at targets and a cop thought it was a real riffle

rich.schnippel made it! (author)2015-03-23

This is the airgun that my 13 year old son built for the Science Fair...he won his school division, city division and regional division...we went to the state level this weekend, but he did not win. His project was determining which style of handmade nail-dart was the most accurate based on the fin design. Nice project...he did a great job!

WilmerV1 (author)2015-03-14


DanX1 (author)2015-03-12

This is great! Thanks!

PandoodleR (author)2015-02-24

The video is unnavailable!!

glmitchelljr22 (author)2014-12-07

I just made one similar to this one but used a momentary switch as a trigger.

runamazondry (author)2014-11-04

That's so awesome i am going to try this.

I thought these were the best cheap airsoft snipers but wow..

But for a home-made airsoft rifle this is so awesome!

How much did that cost? I would guess around $45?

mrzaden.kirk (author)2014-10-27

can someone make me one I'll pay 50$ to 65$ for one kik me at kikzaden or snapchat me at zadenk plz reply if u can thx.

Master_Pollo (author)2014-08-01

how did you mod the sprinkler valve ?

Managinis (author)2014-05-13

can u move the trigger up????

Managinis (author)2014-05-12

hay how much dose it cost????

ikhan26 (author)2014-04-18

hello there I Hv gathered all parts and before I start making it a few questions..... how do you calculate air pressure in chamber. there is no psi meter. also can I attach psi metre on the left of quick disconnect valve?......

Grold (author)2014-03-03

I just wanted to ask is it possible that i could modify it to a paintball gun?

ikhan26 (author)2014-02-22

Finally after a long search i ordered sprinkler valve online store. it is of Rainbird brand. it has one solenoid on top at one end. it is black in colour. i hope it will work,....

ikhan26 (author)2014-02-05

hello irwinner I Hv been looking and reading all this info here. it's greatly helpful. much better than other air rifles made from pvc. so far I Hv tried hard in and around my area to find Sprinkler valve but no luck. I recently found Sprinkler valve online store in USA. before I place an order I want to confirm that it is orbit open jar online valve with two sides open like in pic. but it has some black part attached on top. so if could just clarify then really I would go ahead. now I am just waiting for reply from you ..... till then I'll keep my fingers crossed.

keyondre (author)2014-02-03

Is the sprinkler system a: "orbit 1 in. NPT green jar top valve"?
because thats the closest one i found i think it may be the same one.
Other than that i built it today and spent 75$ on everything, although i
had an air chamber built for a previous one i made, the valve was
already in it. So i re-used it because, it was the same exact design.So
if someone wanted to go make this now, id say depending where you live
it may differ( but im in PA) if ur buying the air chamber id say its
roughly $85 overall. Assuming (4-5$ for tubing, 4$ for fittings, and the
rest is tax).Ill post a pic once i finish it and paint it, im waiting
on the stupid orbit bulls#!% to hook stuff up, and test it.

nhstillman (author)2014-01-17

Do you think I could modify the barrel to shoot crossbow bolts?

nhstillman (author)2014-01-17

Can you provide a working link for the video? The pictures are great and all but I am more a visual person because I like to build my projects along with "someone" (in this case, the video). If not, that is ok. Either way, this is a great build!

MadBomber12 (author)2012-03-04

This is ganna sound stupid, but what's the best ammo for this rifle?

smehta6 (author)MadBomber122013-12-19

Marbles or Nerf Darts, worked for me

hanelyp (author)MadBomber122012-12-27

I'm thinking marshmallows would work well.

zelback1 (author)hanelyp2013-07-28

I think that they would explode on the way out. lol.

crazypilot008 (author)2013-11-04

irwinner its wonderful work you have done can i change the barrel size to use it for paintball ammo

philip1982 (author)2013-08-05

THIS PROJECT IS AWESOME!!!!!!!!!! Thanks @irwinner!

ychin2 (author)2013-05-24

hi there! this is an awesome intructable! i was hoping to build it for a physics project.
but i was wondering if it were possible for me to connect the gas reservoir to the blowgun and subsequently connect it to the bolt assembly directly, and bypass the sprinkler valve? would it post any safety hazards, or reduce its power?
it is my first time building a pneumatic cannon, and i dont really know how these stuff works.

jaykay007 (author)2013-01-18

About to make this model, Upload images after its completion

Denasdc (author)2012-11-22

And also: Why do u need coupling in the bolt action?

Denasdc (author)2012-11-22

Hello all. I'm planning to build this one with few little changes to it. But i have only one problem considering this: When the bolt action is set up: the barrel itself will move up, or it will stay and the other piece with same diameter will move to the barrel? I just can't get it. Will you help me this?

cade nielson (author)2012-11-19

i im thinking of making this about how much did it cost you?

MakarovII (author)2012-11-02

This is a good airgun what is the projectile of this stuff reply me cause i made one and i appreciate your work good job...

fr05ty911 (author)2009-11-19

instead of gluing the chamber in could you use a quick disconnect so you wouldn't have to keep refilling it and just swap chambers???

djzadjza (author)fr05ty9112010-01-02

thats a god idea but the disconnect might be two small so you would have to use some reducers.
but that would be a very good idea if you were using the gun away from an aircompressor... infact i might try that

deobomb (author)djzadjza2011-08-28

yeah you could make it snap on and off to make a fast change air tank

shaclonts (author)deobomb2011-11-20

Wouldn't that not work because the whole idea of the compression chamber is to quickly release the air? If you could do it that way you might as well keep it attached to the compressor and forgo making the compression chamber altogether.

Syn7 (author)shaclonts2012-10-15

or use a real tank and have multiple shots. It's not the same. The whole concept here is a complete release in one shot. Hooking it to a direct infinite source requires a slightly different design. There are lots on here, just search.

Syn7 (author)Syn72012-10-15

Although, you could just carry a pressurized tank with a scrader valve filler attachment and use that to refill your pvc canister while in the field. Prolly a good idea to have a guage handy if you don't have one built in with the valve.

popcannon (author)djzadjza2011-12-09

maybe u could hav a hwhole second tank with a female disconect at one end and a male discnnect at the other, so u could fill it at the commpresser and then when u wanted to use the cannon away from the commpresser u could fill from that

hunter1125 (author)2012-07-04

So if you pressurize the tank to 100 psi does it shoot well, and does tank size have a factor besides amount of shots?

mamajr96 (author)2012-05-29

Couple questions, do you have to use an air compressor to fill the tank each time can't you mount and second tank filled with air and leak it into the other tank to re-fil the main tank. This is a dumb one but I'm guessing you have to re-fill the tank each show right

jumpup_dnb_dj (author)2012-05-11

The term 'rifle' is not meant to be taken in the literal sense. The term 'rifle' has been used to describe a variety of weapons that use a stock and is to be shouldered before one fires it.

This is a fun instructable and I don't believe the accuracy of what you speak of here is required.

So the owner of this instructables use of the term of 'rifle' is more than acceptable.

Zach the Man (author)2012-04-09

and is it only one shot?

Zach the Man (author)2012-04-09

i think my jaw just fell off my face when i saw that thing

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