I'm revamping a project boat on a budget, and I enjoy home gun crafting, so when gathering of all the required/necessary equipment & saw the ridiculous prices wanted for flare guns (also dearth of availability: finding a lot of "sold out's") and their being such a simple build, I started looking around for plans online.

Plans aplenty, but they didn't answer some of the most basic questions:

1.   If it's possible to fit a 12 gauge shell into the flare gun, does that make it a pistol shotgun, and thereby classified as a firearm?

2.   Is it legal to have a pistol 12 gauge shotgun?  Although it is my intention to build a flare gun and use it for distress signaling, it wouldn't bother me to be able to chamber a 12 gauge shotgun shell.   As long as it's legal, that would be the simplest way to go.

That would be so much easier than trying to figure out how to put in denial features to prevent a 12 gauge round from being put into the flare gun.  

It would also make producing rounds for the flare gun easier. I began my reloading career back during high school decades ago, and I would be quite comfortable loading up 12 gauge shells with flare accouterments.

3.   So far as I've been able to learn, "powers that be" are in process changing rules to where you can't build your own firearms, but as for now, it's legal building a flare gun?

There are 12 ga adaptors for 37mm flare guns. But unknown if you can fire shot shells from them.

Digging through YouTube videos, I did find out there is such a thing as a 12-gauge pistol... But it doesn't look like it would be anything pleasant to shoot ... https://www.youtube.com/watch?v=fQR21EcH8Rs

Research indicates can register 12 gauge pistol as a "short-barrel shotgun" or "any other weapon" under NFA, but you do have to pay a $200 tax for SBS or AOW (if making from scratch as a pistol), and wait typically 6 months for approval, before beginning constructing 12 gauge pistol.

It looks like most practical legal work around for constructing a flare pistol, would necessitate denial features making it impossible to insert a 12 gauge shell into flare gun.

One method that immediately comes to mind, would be having a pin sticking out barrel breech which would fit into a matching hole in breach face.

By constructing 12 gauge flares with a notch in rim to accommodate barrel breech pin, you could make 12 gauge flares which would fit, but you would not be able to chamber a 12 gauge round, which lacks notch for aforementioned denial breach pin.

Whether or not this would be enough to make flare gun legal,  avoiding issues of becoming a 12-gauge pistol firearm? IDK  Depends on politics?

12 Guage Flare Gun

You can find the same item in Walmart for about 46 bucks, and occasionally you'll catch one on clearance for $10.  $10 bargains get snatched up quickly! lol

https://www.walmart.com/ip/Orion-12-Gauge-Alerter-Basic-4/16326927

Since I enjoy DIY home guncraft, part of the fun is learning, designing, constructing, and testing.

As far as I can tell, it's legal to go ahead with construction of a 12-gauge flare gun, as long as having denial features and cannot accept 12 gauge shotgun shells.

Our State has no prohibitions against flare guns, and the only State I know classifying flare guns as firearms would be California, go figure.

A few hardware store ingredients, some scrap metal, Dremel, grinding, sanding, welding and hacksaw work, and "Bada bing, bada bang" There You Go! ... one flare gun for the project boat.  :-)   What's not to like?

I can't speak to the legalities in the US, as this was in Africa, but a 12ga handgun was a hoot to shoot.  Local built single shot derringer that was sketchy as all hell but fun to hunt doves with .  Design and construction can be pretty simple.  If you need to add a denial pin that would be simple enough.

The commercial 12ga. flare guns avoid being NFA items in two ways:

----- #1 = The flare gun is built of weeker materials such that firing normal pressure 12ga. shotgun ammo in them will blow them up in your face.  But are strong enough for the 12ga. flare rounds which opperate at a lower pressure.
----- #2 = The chamber and 12ga. flares that go in it are shorter full shell diameter and the flare part that is shot out that is long steps down to barrel diameter such that a normal 2-3/4" 12ga. shotgun shell will not fit in the chamber.  It's just like 38-spl. & 357-mag.  It's supposed to be one way compatible so that you can shoot 12ga. flares out of a 12ga. shotgun but you cannot shoot 12ga. shotgun shells out of a 12ga. flare gun.  Just like you can shoot 38-spl. out of a 357-mag gun but if you try it the other way around it won't work.  Of course the little shorty 12ga. shotgun shells are an exception and will fit in a flare gun but will blow it up (see #1 above).

Although I cannot guarantee that if you followed the same two points that the commercial 12ga. flare guns do you would be good to go if I were to attempt this project that is what I would do.  3D printed plastic and/or aluminum would be my materials of choice to get that right strength level where it's strong enough for the flares but weak enough to blow up if real 12ga. ammo was attempted (shorty shells of course because I would also cut a short flare length chamber = buy a box of flare loads and measure them and cut chamber depth accordingly).

Good information that you've brought up, & good to know :-)

Since I'm contemplating building a one-off prototype that's going to sit in a flotation box inside my fish ski boat (and hopefully never have to get used (!), I may not have to go as far as commercial flare gun manufacturers mentioned, who need to concern themselves with civil liabilities & that sort of thing?

The simplest and easiest way I can see going forward with the basic concept is to purchase a box of cheap 12-gauge target loads, dump out lead shot (save shot for casting fishing weights and/or bullets), purchase affordable, readily-available red road flare, then cut chunks out of flare to put into 12-gauge shells in place of lead shot removed.

These 12-gauge rounds would need to be modified to work with whatever denial features chosen for prototype/experimental one-off flare gun.

Being thrifty, admiring reuse/recycle and making clever use of scrap materials, I looked around to see what's on hand.  It looks like an old piece of sheet metal would work pretty good for outer sides, & can't see any reason why inner core shouldn't be a piece of plywood as a spacer, some old bed rail chunks left from a folding ladder project for the metal trigger/hammer and components.

Handle/grips could best be made with silicon?   Red Rit Dye in the silicon mix (or red rtv silicone) would match up with red paint for remainder of flare gun.  3/4" O.D. black iron pipe nipple (smaller I.D.) and hardware springs/ screws would complete needed materials.

If your going to cobble together your own flare rounds as well not just use the commercial 12ga flare rounds then you miz-well just go full muzzle loader and be absolutely safe from NFA item classification and also be able to legally load shot, buck, ball, & slug as well.

Just buy a length of appropriate 12ga internal diameter tubing and cut a bunch of like 4" lengths and turn some base plugs with 209 size primer holes in the middle and weld them into one end of your 4" lengths of tubing and then make up a batch of like 3" long lengths of 3/16" by 1" flat stock and punch 1/4" holes in each end all the same and weld them to what will be the bottom of each barrel.

That will give you a whole batch of quick change muzzle loading barrels that you can legally stuff with whatever you want.

Then use some aluminum flat stock to build yourself a pistol grip frame with a milspec AR-15 fire control group and firing pin and two captured pull pins in it for barrel mounting.  And you just swap in a fresh barrel unit for a reload just like you would mount an AR upper with the two pins only mounted 2-1/2" or so appart to match the 3" long bottom mounting rib welded to the quick swappable 4" muzzleloading barrel units that you have mass produced in a small batch and have a bag of pre-loaded!

My two cent two thoughts.


A rim oriented denial device where you have to match the round orientation is slow, awkward and only you will know about it.  Think fumbly with cold wet hands,...a tilting deck or you’re standing in the upside down boat.  Keep it simple, you will be using this when your life is in danger.

Make your own shells? pffft.   What is your life worth?  You want them to be somewhat water resistant.   I have shotgun reloaded, you will be hard pressed for a crimp that will be water resistant......the real threat is water vapor over time,....that fusee phosphorous will be sucking water out of the air.  I have tossed dozens of them that lived in patrol,cars that got a bit too much rain moisture.


Free third thought.   Your home made shells won’t be USCG. approved.  They won’t count for a boarding inspection if it is a required item on your size vessel.   That said as a long time boat operator, I kept the minimum up to date USCG flares and shotshells AND I KEPT THE EXPIRED ONES ON BOARD IF THEY WERE STILL IN GOOD CONDITION.  More is better!  I had a whole .50 cal can of out of date shells and hand flares for training or real emergencies.  And use the out of date stuff first if you got time and are safe to consider them.  

Oh and the regular hand USCG hand held flares do swell up if they get wet and fall apart.  

I believe I will follow along with the route I've contemplated and chosen, however, you bring up a lot of salient and interesting points :-)

If you ever make one of these builds like you're describing, I hope you post with pictures :-)  

Lot of folks would be intrigued seeing what you've come up with.

Good thinking :-)

Seems kind of a silly lot of effort to go through, taking a home-grown flare gun for one boat, and having to get Coast Guard approval? idk

I would guess that if flare gun is built such that looks like a cloned, well known commercial product?  "If it looks like a duck and quacks like a duck"

You would be amazed at the number of people, when expecting to see something, they'll see exactly what's anticipated LOL

Kind of hard to perceive, but Lake Perry Kansas actually has a Coast Guard auxiliary presence.  I became aware, when taking a sailing course they offered.  

At the time, I don't recall whether they were doing inspections, but I believe they had voluntary inspections, which weren't official, but would help you get up to snuff, so you would be all up to speed and legal, if you were to have an official inspection.

Revewing requirements for my fish/ski sized boat, found required Kansas equipment here: https://ksoutdoors.com/Boating/Required-Equipment-Checklist#title

Here's an interesting thought: could you build a 12-gauge flare gun pistol with a denial pin, keep on your boat for safety gear, and apply for a $200 AOW designation?  

If this is legal, you'd have use of flare gun in your emergency kit, while waiting out typical 6-month ATF approval process, then remove denial features, once approval has been granted? idk

12-gauge flare guns have a barrel that won't take a 12 gauge shotgun shell. The flares are narrower at the end that goes in the gun.

Why would a 12 gauge be any different from 410? They sell a lot of Taurus Judges Which are 410 gauge shotgun pistols?

It's the same $200 to make an AOW as an SBS not $5. $5 is the transfer tax on an existing AOW.

Wonder if a mini shell will chamber in a flare gun. That could be a big deal.

@PursuitSS Thought the top one was some weird concept that didn't even function as an actual shotgun. Where can one buy the top one?

The Judge is a 45 Colt pistol that also chambers 410 shotshells and has a rifled barrel.  If it were smoothbore it would be a different story.

.729 in (18.5 mm)

Why not make a .729 AFCOM express?

What? .729 is either a DD or AOW

Taurus did have a 28 gauge pistol that they wanted to inroduce a few years ago but fell victim to the 1/2" max bore rule by a hair and it disappeared.

Well then I guess you have never heard of a .700 Nitro Express or the .950 JDJ (24.1x70mm)

The J. D. Jones rifle is chambered for  0.950 (24.1 mm). SSK received a "Sporting Use Exception" to de-regulate the rifle. Thus, in the United States, they can be owned like any other Title 1 rifle. The rifle has a McMillan stock and thick Krieger barrel bearing an 18 llb muzzle brake

They had to apply for and receive the exemption before building them.

Yes, the Agula mini shells will drop right into the plastic/aluminum commercial flare gun pistols since their primary denial means is a short chamber.  However, that is where their secondary denial means kick in, they blow the heck up and can't take the pressure.  (No I didn't try it myself, YouTube has videos).

Yes, the primary denial method of the commercial flare guns is that they have a chamber which is cut shorter then a 2-3/4" shell when crimped which is normally the shortest shotgun shell commonly available.  However, they also have a secondary denial feature, they don't make them out of plastic and thin aluminum just for cost & weight reasons they are also built just strong enough to handle a flare load but weak enough to blow up in your face if you fire a real shotgun shell in them.

You can fire the 12ga flare rounds from a normal shotgun (although not all pump/auto actions can handle their length, break action guns they work in fine).  It's supposed to be that way, one way compatible.  You can fire the 12ga flares in a 12ga shotgun but can't successfully fire 12ga shotgun shells in a 12ga flare gun.

Found one. That's about what I expected.

Live shell is loaded at 5:00 mark if anyone just wants to see that happen

From my researches on different DIY builds, as far as the construction goes (leaving aside for now detailed legalities), this is about all that you would have to have for a functioning DIY flare pistol:

Don't know if this will come through, unless you have Pinterest?

Photos come from this DIY book.  Again, don't know if link will work unless you have Scribid?  idk

Would need to adapt basic idea to 12 gauge flare gun, and meet legal requirements...

I've built most of those....they're fun in a stupid giggles sort of way.

HHHHhhhmmmmm... Addressing these very real concerns you've mentioned...  

Perhaps the best "work around" to "rim oriented" denial devices, would utilize shot shells which had been resized in reloading die to slightly smaller than standard 12-gauge rounds.

This would come with the advantage being able to use standard 12 gauge reloading gear, needing only to insert a "reducing collet" into standard die, to control "smaller than standard" 12 gauge resizing.

A "smaller than standard size" 12 gauge chamber would make it impossible to insert a standard 12 gauge shotshell, satisfying legal "denial device" necessities, and avoiding fumbling with "rim oriented" denial device concept.

In a similar manner to putting a reducing collet into a standard-sized reloading die, a piece of 3/4 inch outside diameter black iron pipe could have a reducing collet sweated into pipe; creating a "smaller than standard" size chamber, which could not accept standard 12 gauge shotshells.

As far as waterproofing?  Keeping out moisture phosphorus flare would suck out of the atmosphere?  That is an interesting and intriguing problem to solve.  

A couple of thoughts come to mind: wax poured over crimp to seal out moisture or other form of sealer/silicone/shellac, etc.

For example, rounds loaded for military have a form of sealer around where primer fits into shells. I wonder what's used, and if such presents some possibilities?

Waterfowlers and others working in wet environments must have run into this issue before, and doubtless could suggest some good DIY solutions that have worked out for them?

I went into Wally World Sporting Goods Department today and there was not even one box of ammunition on the shelf.

They were sold out of flare guns and flares as well, go figure?

Managed to purchase a new starting battery for my fish ski boat (some Walmart's were completely out of marine batteries last week) and other accouterments, but appears I'm stuck with DIY scratch build, if I want flare gun for boat's safety gear tomorrow.

For $8.20 worth of hardware store ingredients, scrap metal and silicon sealer on hand, hopefully I'll be able to finish up a flare gun for the boats safety Locker ASAP?  idk, depends on if there's any pesky interruptions! lol :-P

Means of 12 gauge shotshell denial chosen to pursue: making chamber too small to fit a 12 gauge round.  

I'll see if can document build with series of pictures and accompanying explanations.

Was hoping to be finished with the one-off experimental prototype 12-gauge flare gun for fish ski boat, but that was not to be.

I got started with cardboard, making cutouts for trigger and Hammer and positioning springs because I have found making mistakes on cardboards is quite easily remedied and cheap, when I discovered that the entire sack of hardware store ingredients needed to go further, had gone AWOL.

Well, that was a pretty funny one... found the missing hardware items to build flare gun for fish ski boat... I noticed that the cat was lying on something that was sticking out from underneath her... I didn't want to disturb the cat, she's "disturbed" enough already LOL ??

Usually it's the dog ate the homework, but this time the cat was sleeping on the parts that I was looking for ... I found this out after I'd already went back through the trash thinking it might have been thrown out with empty bags LOL??

On that note, my interest and enthusiasm for completing the flare gun today seems to have waned and I believe I will start again tomorrow after work  :-)

Just a note, did you do know they make aerial marine flares that don't require a pistol launcher?



Pocket Rocket

took the words out of my fingers.

I understand wanting a project and all.   A friend’s father built himself a single shot .22 target pistol out of an old pellet gun.  He even licensed it as required.  The project made no sense other than it was a project.

You are quite correct in describing a project as worthwhile in and of itself, for the fun of learning, designing, building and testing.

I'm working on concepts for different types of aerial flares, and I can see the potential in building parachute flares.

Somewhat along the lines of an Estes rocket, using 12 gauge lifting charge igniting a delay charge (to get flare far enough away from flare gun), before sugar rocket motor ignites, taking flare up a thousand feet or so, when ejection charge deploys parachute.

Length of experimental parachute flares will most likely be majorly deciding factor of barrel length for flare gun pistol, I think.

Yesterday we got rained out of work, so I decided to do some more on the flare gun project.

I am taking pictures but I've been having a few issues trying to figure out the web hosting for where to park pictures and decided that imgur.com is probably the best place to go.

Started out by laying the piece of rigid conduit on a clipboard with notebook paper, & drawing the outline of barrel, adding features to the barrel and going from there.

As far as figuring out the arcs and swings of pieces like the trigger and Hammer, I placed the drawing on an old Cheez-Its box (I'm thrifty, I will save a few boxes for making gaskets and such:-), held in place by push pins.

Where the pivot point is for the Hammer as example, a strip of cardboard was held in place with a push pin and a hole punched in the cardboard at necessary distance such that I could use a mechanical pencil and swing the cardboard in an arc from the push pin pivot to get the correct clearances for the hammer.  

I couldn't remember what I had done with my compass for drawing arcs, so I used this poor man's version, which worked fairly well.  When I can get picture posting sorted out, I'm sure it will be much easier to see what I'm describing lol.

After grinding away burr on the end of rigid conduit, I was surprised finding out 12 gauge round fits inside, so now I'm back to figuring out denial features.

The path I'm contemplating following, would be to cut a piece of rigid conduit, split lengthwise, then squish split closed, such that I can use this as an insert into conduit barrel.  Then there would be no way 12 gauge round could possibly fit into this barrel :-)

One way to go about this task: Heat conduit barrel to expand, while freeze insert to shrink it. Hopefully, this would provide necessary clearance to be able to drive insert into barrel, and if needs be, I could always braze or solder insert into the barrel for permanency. idk, have to see what works out.

If your not a member you might want to checkout Weapons guild. You will find a more helpful crowd there.

I hope you don't plan on using the conduit for the barrel. I know it's a flare gun but there is no reason to over build it.

I'm one of those kind of people that always over builds and over-engineers anything created for myself lol.  I prefer for things that are built to last.

I'm pretty much comfortable with three levels of back up, because I've had primary, secondary and backup systems fail before :-)

I am a member over at weapons guild, but I haven't posted much over there, because John Q Public can't see posts unless they're a weapons guild member.

ar15.com build-it-yourself forum, anybody can see anything posted, if they're curious and want to know.

Besides, signal flare gun's a tool, not weapon.  Flare meant for use in case of distress on a fish ski boat like mine, although I'm considering adaptations that would allow to be a life line thrower as well  :-)

I've "way lot" of restoration to fish ski boat before going on the water, when I'll need flare gun for safety gear.

Subject doesn't engender too much forum interest, so no hurries regards posting progress reports lol

Since no hurry getting flare gun project put together, I'll post with pictures/explanations when job's completed.  

Doesn't every boat need a 1 7/8" (diameter of a golf ball) signalling cannon?

1. If a 12 ga shell fits it becomes an AOW.
2. If registered as an AOW

12 ga flares are shorter than 12 ga shotshells, about a 1/4 inch.  If the chamber is made to flare dimensions a shotshell will not fit and it is a flare-gun.