Introduction: Convert a Spring Airsoft Gun to Full Auto
For suprisingly little money and effort, you can convert a single shot airsoft gun into a rapid fire BB hose with an insane rate of fire.
The concept is simple: put a constant supply of high preassure air through the gun, and bbs will simply follow the airflow out the barrel. This means that this gun will fire as fast as the magazine can feed.
I recommend you get the highest capacity magazine you can find for your gun. Mine goes through its 30 rnd mag in about half a second (no exageration).
Step 1: Selecting a Gun
The airsoft gun you choose for this build should have a 'T' style hopup unit. This type of hopup unit is internally shaped like intersecting tubing in the shape of a 'T' . Many spring shotguns and some low-end electric guns have them
Step 2: Open It Up, and Gut It.
Its up to you how to figure out how to open your gun, as this could be done with any number of guns, which open in as many different ways.
After you have it open, take out any part that is not related to the hopup, barrel, or magazine This means you should leave in the magazine catch (the part that holds the magazine in), anything that helps to hold the barrel or hopup in place, and any levers or slides used to adjust the hopup.
Step 3: Aquire or Create an Air Source.
If you have access to an air compressor, that is ideal, but for those of you without one, an air supply of sufficient power can be made or aquired relatively inexpensivly. Our objective here is to have a large supply of air behind a 'momentary' valve, (meaning a valve that will only release air when it is held down). The air source can be attached to the valve in any way that is convinient. I would suggest that you go to your local hard ware store, and look at what you have available to you. You could even dry fit the various parts in the store to find out what would fit.
An easy valve to use would be an air compressor specific 'blowgun', but any momentary valve will do. I used an preassure washer handle and enclosed valve, because it had a nice trigger system ready to go.
For an improvise airsource, you could use 2 inch pvc pipe with a cap at one end, and reducer fitting on the other, which would attach to a blowgun. (explained below)
You could also use a bike tire co2 quick inflator, but you would spend a fortune on 12g co2 cartriges.
Step 4: Airsouce to Hopup
Now you need to find a way to put the air from the momentary valve through your hopup. I used .25" flexible tubing glued in the back where the air nozzle used to be, but you could similarly use something like a pen tube. Be sure not to obtsruct the opening through which BBs come from the magazine. The other end of whatever tube like ogject you used needs to be attached to the output end of your valve in a reasonably airtight manner.
Step 5: Load and Shoot.
Now just mount your valve and gun together in whatever manner is convinient, charge up your airsource, load the gun, and open the valve. If you did it right, you should hear a fart like noise as you send your entire magazine worth of BBs down range faster that you thought possible.
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19 Comments
Question 1 year ago on Step 1
I was wondering if a FNS-9 would work?
11 years ago on Introduction
How fast do you think my 10 round clip will go through? No joke, I have a TEN ROUND pistol clip from Japan. Don't laugh at me, I am an expert at pistol marksmanship.
Reply 10 years ago on Introduction
if your an expert at it why are you on an airsoft gun thread isntead of a real gun one?
Reply 10 years ago on Introduction
My air soft pistol was notoriously inaccurate. I actually don't even have a gun anymore. Threw it out in favor of building lethal versions of tear gas grenades. But the pistol, I knew every way to score a hit with it. Until it got hit by a BB from my friend's gun. That made it more inaccurate and at that point I just threw it out. As for actual guns, I go with my girlfriend to a range every weekend. There is where I honed my skills with a pistol. More accurately with a .44 magnum revolver. Thing has some kick to it. So, yes, I am a pistol marksman, no I don't have an air soft gun anymore, and have a great day, Hornbadoing.
Bendog38
Reply 11 years ago on Introduction
I'm not sure this would work with pistol mags, but i would guess it would take about a sixth of a second to dump ten rounds.
Reply 11 years ago on Introduction
any one who has played quantum of solace in the Wii will know about the 'bomber' character that can be selected in multiplayer. his gun fires 2 shots the instant you pull the trigger and has to be slowly reloaded after that.
seems fimiliar? if you are using this you shouldl play defense. keep your gun hooked up to the pump and have a bucket of bbs nearby.
PS. this is a good idea but i think i will stick with my more controllable spring gun.
due to the pump i can squeeze out an accurate 2 rds per second.
Reply 11 years ago on Introduction
The purpose is more novelty than anything. If you were to actually use it, you would probably get the most out of it as a masterkey mounted shotgun. Each "shot" would require a mag change, but it could probably clear a small room.
Reply 11 years ago on Introduction
well yours should take about a tenth of a second to empty. i have made things like this that empty a full 2000 round can of bbs in like thirty seconds.
11 years ago on Introduction
Do you think you could make it only semi auto so you don't blow through a mag that fast?
Reply 11 years ago on Introduction
I'm afraid not. That would require a much more complex system, perhaps with some combination of 3-way valves, QEVs, and perhaps a spool valve.
11 years ago on Step 3
thanks so much molybdenum, your idea helped me alot in a project im thinking of!
12 years ago on Introduction
Oh oops. I thought you meant put the air in front of the bbs and when the gas flows out, the bbs will follow the air like a magnet.
12 years ago on Introduction
Nice job but won't it be simpler to put the air force behind the bbs?
Reply 12 years ago on Introduction
um, this does put the air force behind the BBs. this is about the simplest possible design for an airgun.
12 years ago on Introduction
Like a gas gun?
12 years ago on Introduction
how did u paint the stock.
Reply 12 years ago on Introduction
White spraypaint base with acrilic paint over it, followed by a clear coat.
12 years ago on Introduction
how much fps does this shoot
Reply 12 years ago on Introduction
Depends on how much preassure you put trough it. Strangely, I found that at preassures above about 50psi, Hicaps dont feed right, but spring mags feed fine, meaning that If you want to use something like 100psi and get a higher muzzle velocity, you would have to use low/midcap mags.