Introduction: DIY Airsoft Cap-gun

Picture of DIY Airsoft Cap-gun

This will show you how to make a cheap airsoft gun out of a cap gun. This is not to be relied on in an actual airsoft battle. It's just a fun project to try.
Please Rate!!
7-31-09: Today I found that 12hippos posted the same project as me, but about 6 months earlier. Please note that I did not copy him, as I did not know the instructable existed. If you really want to see heres the link.

Step 1: Get Your Supplies

Picture of Get Your Supplies

You will need a cap gun revolver. I got this one at Albertsons for 2 bucks
You also need caps. I got a pack of 24 cap rings for a buck at Albertsons
You need airsoft bb's (of course). You can get these at wal-mart or any sporting goods store.

Step 2: Widen the Barrel

Picture of Widen the Barrel

Use a knife or a pair of scissors to widen the barrel so a bb can pass through. Make sure it's wide enough by dropping a bb into it. The bb should pass right through.

Step 3: Insert the BB's

Picture of Insert the BB's

The gun I have has a removable cylinder, which makes it easier to put in the bb's. Check the picture to see where to insert the BB's. After you have put the bb's in, you need to push them down as far as they will go. I used a screwdriver.

Step 4: Reassemble the Gun

Picture of Reassemble the Gun

Put the cylinder back in (if you removed it) and put the cap ring in,

Step 5: Use Your New Airsoft Gun!

Picture of Use Your New Airsoft Gun!

Your airsoft capgun is now ready to fire. Always use eye protection when firing the gun, the bb's are prone to ricochet.

Step 6: Improving Accuracy(optional)

Picture of Improving Accuracy(optional)

I managed to increase the accuracy of the gun by hot gluing part of a pen tube to the barrel. Another section of the pen tube is placed inside the gun, as seen in the picture.


tyeo098 (author)2011-04-14

This is a firearm.

"any weapon (including a starter gun) which will or is designed to or may readily be converted to expel a projectile by the action of any explosive;"
-18 USC 921

The projectile that is expelled is the .12g plastic BB, the explosive is the cap.

Its not illegal (unless you love in NY or Cali, or IL w/o a foid card) but you need to be over 18 to even possess it.

All firearm rules apply to this.

In some states, the construction of this w/o a gunsmithing license is a felony, and ill land you in jail for more than 5 years, and remove your right to vote, own a firearm, etc.

usarmymp223 (author)tyeo0982016-09-30
via ATF's Q&A sectionDoes an individual need a license to make a firearm for personal use?

No, a license is not required to make a firearm solely for personal use. However, a license is required to manufacture firearms for sale or distribution. The law prohibits a person from assembling a non–sporting semiautomatic rifle or shotgun from 10 or more imported parts, as well as firearms that cannot be detected by metal detectors or x–ray machines. In addition, the making of an NFA firearm requires a tax payment and advance approval by ATF.

[18 U.S.C. 922(o), (p) and (r); 26 U.S.C. 5822; 27 CFR 478.39, 479.62 and 479.105]

LancerD1 (author)usarmymp2232016-10-02

I'm just merely interested, what if someone in Canada was to do this?

Gozzo (author)LancerD12016-10-23

Buy liberal amounts of KY Jelly for your going to prison bag. Although here in Australia some Prisons will Issue you with Rubbers and water Based Lube, When asked by your cellmate if you wish to play " Mummies and Daddy's " ALWAYS ask to be Daddy. However most of the time in these situations Mummy will be a Pre - Op Trannie.

Sorry couldn't help myself, seriously though, most countries in the Commonwealth mere possession, will almost certainly attract stiff penalties. Manufacturing will certainly get you in the deep end. I believe Australia and Canada have similar Gun Control Laws. Here in Australia you can expect SERIOUS Jail Time, and Deportation if your not a Citizen.

LancerD1 (author)tyeo0982016-10-02

I'm just merely interested, what if someone in Canada was to do this?

dzm_d (author)2017-07-23


Javin007 (author)2009-07-01

How hard will this launch the BBs? My experience with plastic ring cap guns is limited. I'm curious as to how much gas they will produce.

chocowubbles (author)Javin0072009-07-01

I managed to dent an aluminum can from about 15 feet. It packs a pretty good punch, and only hurts as much as a regular airsoft gun. The tricky part is aiming, because this thing is pretty inaccurate.

~Aeronous~ (author)chocowubbles2009-07-25

well is there any way to make it more accurate? o and what size are the bb's?

chocowubbles (author)~Aeronous~2009-07-25

Well, adding the pen tube is the only way to make it more accurate that I have tried. Also, I use 6mm bb's .12 grams. The biggest problem is that the gun itself is extremely low quality. Mine is starting to fall apart, and I've only fired about 50 bb's. The fact is, this is just a cool project to try with your old capguns, not a reliable weapon to go airsoft with.

zimmemic25 (author)chocowubbles2009-08-06

there would be another way for improving aiming: just add 2 BBs instead of 1, so you have something like a small shotgun. i didn't try, but i think it could work

Gozzo (author)zimmemic252016-10-23

To much weight, friction, and resistance. Remember it's a novelty project not a real gun so don't expect that kind of performance, as that is just a plain silly expectation.

Scar16 (author)zimmemic252009-11-10

they just shoot off in different directions

Gozzo (author)chocowubbles2016-10-23

However if you were to paint it black or silver and a cop see's/hears you fire it expect to be shot when you turn around, unless you drop it and raise your hands palms open before turning to face a LEO, from his perspective it went BANG and there was a Muzzle Flash remember the poor guy only has SECONDS to react.

airsoftman559 (author)~Aeronous~2009-07-28

normal 6mm

Javin007 (author)chocowubbles2009-07-01

LOL! Still, pretty cool. Is it still as inaccurate with the pen casing inserted? I would think that would help with the accuracy somewhat.

chocowubbles (author)Javin0072009-07-01

It does, but I have yet to develop an aiming system that goes beyond point-and-shoot.

zimmemic25 (author)chocowubbles2009-08-06

if this one goes 15ft, i would say its a very-short-range secondary/sidearm, so i think its ok if its not so accurate.

Gozzo (author)zimmemic252016-10-23

I used to own a .32 Calibre S&W snub nose from 5 feet it only dented a fairly lightweight 44 Gallon drum. it's the Nature of a snub nose.

Gozzo (author)chocowubbles2016-10-23

You will find the same problem with a REAL snub nose, thats why they are nick named " Gut Busters " as they are generally a close quarters weapon and often pressed hard against the assailant.

ilpug (author)chocowubbles2010-05-31

i have made these before. I was actually using mine in airsoft. I looked around and found a nicer cap gun for about six bucks. THen i want and got some 6mm brass tubing at the hardware store and put it in for the barrel. active accurate range is now about twenty feet. As far as realism goes, it fits pretty good for a revolver, except the eight shot cylinder. I would like to try and do this with paper caps. I am trying to make an airsoft gun that operates exactly like a real fire arm (cartridges, firing pin, explosive propellant, etc) but shoots airsoft bbs. its in the works.

chubby8 (author)2010-07-05

it also works with air rifle pelets but they only shot a few meters.

Gozzo (author)chubby82016-10-23

which is why you want plastic BB's lead etc is WAY to heavy.

bombmaker2 (author)2010-10-31

I might try the concept but with a .22 starter pistol. That would probably be one of the most powerful airsoft guns ever!

Gozzo (author)bombmaker22016-10-23

I am told with a handle made to hold back the safety mechanism on a Ramset or similar type nail gun might work if you want to go that extreme. However consider that you are going way deeper than mere Novelty Power when using that kind of Primer.

skyfaller (author)2010-10-01

Mine doesn't work , sometimes a bb will fall out of the barrell, other ones get stuck, or fall into the spinning part. The spinning part's hole isn't alligned to the barrel . I don't know how to fix that, so please help.

chocowubbles (author)skyfaller2010-10-02

Well it sounds like a problem with the brand of cap gun your using. I would reccomend just getting a different one. Check out the barrel-cylinder alignment before purchasing. Also keep in mind that these aren't built to fire projectiles, so they lack features that would say, hold the projectile in. I'm sorry I can't be more helpful.

Gozzo (author)chocowubbles2016-10-23

wrap a cigarette paper around the BB, increasing it's diameter but very little weight. Then wet it with Saliva as an adhesive.

skyfaller (author)chocowubbles2010-11-29

by it falling out, i meant that when i pull the trigger the bb doesnt fly out, but it rolls out.

Gozzo (author)skyfaller2016-10-23

See my comment on the directly above post.

prop master (author)2010-12-11

i think this is in genius good work i cant wait to make mine hey and you could just use it like a daringer for last resort i mean come on this cost u 3 bucks it shoots beter than some of the 17 doler ones
ive seen.

prop master (author)prop master2010-12-12

ok i went and bought my gun but mines difernt its smallerand the cilender is more of an open shell but im going to try to make it work wish me luck

Gozzo (author)prop master2016-10-23

I heard somewhere ( wink wink ) you can use air hose from fish tank pumps, to reduce the loss of gas pressure from the cylinder to the barrel to close the gap then muzzle load it.

bbot2000729 (author)2011-07-28

I SOOOO wish i had brought more cash than for fireworks at my street fair a few weeks ago. I saw this EXACT cap gun, and the guy selling didn't feel like bartering any fireworks for it.

Gozzo (author)bbot20007292016-10-23

Mate they cost about $1.00aud from EBay

~Aeronous~ (author)2009-08-01

hey, I just notiiced but its not an airsoft gun, its powered by gunpowder.

chocowubbles (author)~Aeronous~2009-08-01

Well, gunpowder still fires by using gas generated by a small explosion, so in a way, it is. But you are correct in that it is not a true airsoft gun.

zimmemic25 (author)chocowubbles2009-08-06

it is an airsoft gun. because it uses air pressure to fire the BBs. the fact that the air pressure is generated by an explosion doesn't say it's no air pressure. there are airsoft guns powered by methane too, thats also pressure by explosion.

Gozzo (author)zimmemic252016-10-23

Sorry but you are incorrect, it is NOT powered by air pressure. Rather it's powered by rapid expansion of the Gases produced by ignition.

Not methane, propane. And they just use the pressure of the gas, they do not combust it.

aseaheru (author)zimmemic252009-08-16

co2 as well

sharlston (author)chocowubbles2010-03-24

it also not gunpowder its the stff they use on matchheads

2hot2hack (author)2011-04-25

can you use ordinary metal BBs ornot? cos in australia we cant get airsoft.

sanagol (author)2hot2hack2011-09-17

it wont fit in the revolver because a metal bb is 4,5 mm and a plastic is 6mm

2hot2hack (author)sanagol2011-09-18

so wat if i find a metal bb thats 6mm not 4.5??

Gozzo (author)2hot2hack2016-10-23

To Heavy mate.

Gozzo (author)2hot2hack2016-10-23

You can import the plastic BB's without restriction. However you may draw unwanted attention to yourself.

MacGyver1124 (author)2hot2hack2011-07-20

You can try to order them online

chocowubbles (author)2hot2hack2011-04-25

Sorry, metal bb's don't fit snugly so the most of the force goes around and they just fall out.

sswartz2 (author)2011-10-19

arent there plastic things that sit behind the cap? inbox me the answer please. :)

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