Type 4 Explosives Magazine

[NightHawkInLight]

This spring I have set my sights on building an outdoor type 4 magazine. I'm looking for the cheapest way to get the job done in a way that will satisfy the ATF. As I've never built a magazine before, I am not quite sure what sort of power the ATF have in approving or failing a mag. What I mean by that is, if the magazine meets or exceeds all the criteria in the orange book, can it be failed simply for being of unusual design?

 

I have heard of many constructing magazines out of job boxes, which is a decent enough idea. What I am thinking about myself is building one out of a large air compressor tank, something like this or larger: http://centralmich.craigslist.org/tls/2179847871.html

 

It seems like an air compressor tank would be extremely simple to cut a door into, install some interior hinges, a few locks and guards, vent, and bolt to a slab. Give it a good thick coating of paint inside and out to cover all exposed metal surfaces, maybe install some shelves and it's good to go. In my mind it seems more secure than I could ever make a job box. The only thing that worries me is the orange book lists specifically what a magazine "is", which may entirely exclude any shape which is not listed:

 

A type 4 magazine is a building, igloo or “Army-type structure”, tunnel, dugout, box, trailer, or a semitrailer or other mobile magazine.

 

I'm just not sure. It would be the ideal mag for myself, as it would be upright, and large enough to hold multibreaks. Not to mention dirt cheap to construct.

 

Here are the details of a type 4 mag as described in the orange book:

 

(d) Type 4 magazines. Magazines for the storage of low explosives, subject to the limitations prescribed by §§555.206(, 555.210(, and 555.213. Blasting agents may be stored in type 4 magazines, subject to the limitations prescribed by §§555.206©, 555.211(, and 555.213. Detonators that will not mass detonate may also be stored in type 4 magazines, subject to the limitations prescribed by §§555.206(a), 555.210(, and 555.213.

 

§ 555.210 Construction of type 4 magazines.

A type 4 magazine is a building, igloo or “Army-type structure”, tunnel, dugout, box, trailer, or a semitrailer or other mobile magazine.

(a) Outdoor magazines—

(1) General. Outdoor magazines are to be fire-resistant, weather-resistant, and theft-resistant. The ground around outdoor magazines must slope away for drainage or other adequate drainage be provided. When unattended, vehicular magazines must have wheels removed or otherwise be effectively immobilized by kingpin locking devices or other methods approved by the Director.

(2) Construction. Outdoor magazines are to be constructed of masonry, metal-covered wood, fabricated metal, or a combination of these materials. Foundations are to be constructed of brick, concrete, cement block, stone, or metal or wood posts. If piers or posts are used, in lieu of a continuous foundation, the space under the building is to be enclosed with fire-resistant material. The walls and floors are to be constructed of, or covered with, a nonsparking material or lattice work. The doors must be metal or solid wood covered with metal.

(3) Hinges and hasps. Hinges and hasps are to be attached to doors by welding, riveting, or bolting (nuts on inside of door). Hinges and hasps must be installed so that they cannot be removed when the doors are closed and locked.

(4) Locks. Each door is to be equipped with (i) two mortise locks; (ii) two padlocks fastened in separate hasps and staples; (iii) a combination of a mortise lock and a padlock; (iv) a mortise lock that requires two keys to open; or (v) a three-point lock. Padlocks must have at least five tumblers and case-hardened shackle of at least a inch diameter. Padlocks must be protected with not less than 1/4 inch steel hoods constructed so as to prevent sawing or lever action on the locks, hasps, and staples.

These requirements do not apply to magazine doors that are adequately secured on the inside by means of a bolt, lock, or bar that cannot be actuated from the outside.

[dagabu]

Nhil, Passfire has a tut that Lee did two years ago. Type 4 mags are easy to make but are sometimes tricky to get approved. The hardest part is getting local approval.

[NightHawkInLight]

Nhil, Passfire has a tut that Lee did two years ago. Type 4 mags are easy to make but are sometimes tricky to get approved. The hardest part is getting local approval.

Unfortunately I don't subscribe to passfire. Was the tutorial about building one out of a cylinder or a job box?

 

I know a little about the locals around here, I'm not too worried about them. I'm just not completely clear on the ATF side of things. I don't want to go through the effort just to have them show up and deny my mag because of the shape. I guess if that were to happen I would at least be left with one heavy duty meat smoker.

[nater]

Unfortunately I don't subscribe to passfire. Was the tutorial about building one out of a cylinder or a job box?

 

I know a little about the locals around here, I'm not too worried about them. I'm just not completely clear on the ATF side of things. I don't want to go through the effort just to have them show up and deny my mag because of the shape. I guess if that were to happen I would at least be left with one heavy duty meat smoker.

 

The passfire tutorial I saw about a type 4 was making an indoor one from scratch. There might be another project that I've overlooked.

 

The only you would know for sure is to draw up plans and present them to your ATF inspector before building anything. If you go to pyrou, there's a few who've made type 4s with a few variances and wrote up their experiences. The only guys I know with magazines are a couple importers who use shipping containers and one who modified an enclosed trailer to have a mobile mag.

[Mumbles]

Yes, there is no harm in asking for guidance or help from the ATF to see if something would fit into their criteria. Using an address away from where you may be doing any building may not be the worst idea when doing this. One thing to note is that an air compressor tank is likely small enough to be required to be bolted to the foundation. The main issue I see is easily lining the steel shell with wood. It does state "metal-covered wood". To me, this means metal flush against the wood lining. I could see an inspector potentially having issue with this if you had a hexagonal interior or something to that effect. Perhaps you could fill the spaces with the sand/concrete mixture I frequently see cited in the regulations.

[oldguy]

I don't store enough to be of any major concern. I bought a nice looking nonworking upright freezer for $20 from a appliance repair place to store things in. It is in a shed away from my house & workshop, has a locking door, plus I added 2 more hasp's & padlocks for redundancy. It's big enough to suit my needs, is water tight, has shelves, is secure & very cost effective. It's sturdy enough to contain a potential blast, without being so rigid it would fragment into flying shrapnel. About any appliance repair shop has nonworking ones they will sell cheap.

 

In building a stationary permanent magazine, you want to take the nature of any possible worst case explosion into consideration and how it would affect the magazine it is contained in. You want the magazine to absorb the explosion. Rather than attempt to 100% contain it. Because if 100% contained you have a blow out potential (like a cartridge) that can send objects, parts of the magazine or shrapnel flying at high velocities for long distances.

 

Back in the day when I pioneered in large but temporary quarry sites. That would only be in operation a few years. We would set a 20 or 40 ft ocean going steel cargo container on site. Then use a bulldozer and/or excavator to cover it with pit run rock (10 inch minus). Then cap that rock covering over with a couple feet of dirt. The object being the air gaps in the 10 inch material would tend to absorb an explosion & the dirt would have a blanket effect to help restrain / contain any possible fly rock.

 

Most often the weakest point in any magazine is the door entry. Which is where a blow-out effect will most often occur. So, you situate the magazine door facing a hillside. In case of an explosion, the blast force out the door will be directed into the hillside, rather than any work area where people might be. Even then it's smart to build a wall 6 or 8 ft in front of the door, as a blast retaining wall. Of course that type magazine isn't practical for someone with only a minimal amount of chemicals that could possible explode if ever stimulated by some outside or internal redox source.

 

Anymore, because of utterly insane insurance costs to store explosives on job sites. Most temporary or construction type projects don't even have magazines onsite. They simply schedule a delivery to the job site of +5% more than they project to use in any given blast. That can be completely loaded in daylight hours, and set off the same day. Any excess is taken back by the supplier. That holds your insurance costs down as no magazine is onsite. Plus alleviates any issue of theft, as none is stored there that can be stolen.

Edited March 1, 2011 by oldguy

[Mumbles]

I get the impression that magazines are more designed to keep people out, than keep an explosion in or contained.

[NightHawkInLight]

Mumbles, type 4 mags need not be lined with wood:

(2) Construction. Outdoor magazines are to be constructed of masonry, metal-covered wood, fabricated metal, or a combination of these materials.

I know of many people whose type 4 mags are solid steel with a thick coat of paint. All of those who have shipping containers as mags for example. They are almost never lined with wood, unless they are to be used as a type 1 mag.

 

Oldguy,

The point here is not to contain a blast. Magazines are primarily meant to prevent break ins and satisfy ATF regulation. I am not the slightest bit concerned with product igniting inside the magazine. It is 100 times more likely to cause an accident when being handled in everyday use than it is just sitting in the mag.

 

That said, a large freezer isn't a bad idea, so long as the metal lining is 26 gauge steel or thicker to make it ATF approvable. You are then dealing with a plastic lining on the interior of the mag however, which is not a standard material and would require a variance - one I doubt would be issued.

[oldguy]

I get the impression that magazines are more designed to keep people out, than keep an explosion in or contained.

 

True, but you want to consider idiots with rifles & armor piercing ammo.

You would be surprised how many fools think it would be fun to target a magazine from a few hundred yards out.

Also, if a Mag is situated fairly close to a public road, you have to consider worst case & peaple in vehicles on that road.

Edited March 1, 2011 by oldguy

[oldguy]

.

 

That said, a large freezer isn't a bad idea, so long as the metal lining is 26 gauge steel or thicker to make it ATF approvable. You are then dealing with a plastic lining on the interior of the mag however, which is not a standard material and would require a variance - one I doubt would be issued.

 

The freezer I use is double walled metal.

The only plastic lining is in the door.

That plastic lining could be removed with ease & replaced with sheet metal or inexpensive fireproof backing like you use behind a wood stove.

 

You might consider looking into a "rifle safe".

Not cheap, but about as good as you can get.

craigslist has used ones on rare occasion.

Edited March 1, 2011 by oldguy

[Mumbles]

Presumably there is a thickness required for fabricated metal only, vs the thickness required for metal covered wood. I'm interested now if you happen to know what this cutoff is.

[NightHawkInLight]

For a type 1 mag:

 

(2) Fabricated metal wall construction. Metal wall construction is to consist of sectional sheets of steel or aluminum not less than number 14-gauge, securely fastened to a metal framework. Metal wall construction is either lined inside with brick, solid cement blocks, hardwood not less than four inches thick, or will have at least a six inch sand fill between interior and exterior walls. Interior walls are to be constructed of, or covered with, a nonsparking material.

 

14 gauge is 0.064", which is pretty darn thin. Then again, in a type 1 mag you are required to have a heavy interior lining. 26 gauge (0.016") is the thickness I've been told is required for a type 4, but it is not specified in the orange book. I would certainly go thicker. I haven't cut one open yet to find out, but I assume an air compressor tank is about 1/8", about double what is required for a type 1 mag.

[oldguy]

I have been out of it since I dropped my license after 9/11, because of dramatically increased insurance costs. So, I am not up to date. But, if I recall correctly the highest classification for a large capacity magazine required a wall/ceiling thickness that normal civilian pistol, rifle hunting type ammunition would not readily pierce. Even if multiple rounds repeatedly hit the same exact spot. Also any ambient air exchange vent had to be offset baffled with steel plate. To prevent a bullet being fired into a vent, that could hit the mag’s content. Ocean going steel cargo containers with plywood lining inside fit the ticket back then, but not sure now.

 

 

[dagabu]

The freezer idea has some merit but the 1/4" steel around the lock that is hooded becomes the real sticky part to the design. That is one reason why the job boxes are so popular, you can just weld a 1/4" thick sheet over the hood and be done with it.

[NightHawkInLight]

I have been out of it since I dropped my license after 9/11, because of dramatically increased insurance costs. So, I am not up to date. But, if I recall correctly the highest classification for a large capacity magazine required a wall/ceiling thickness that normal civilian pistol, rifle hunting type ammunition would not readily pierce. Even if multiple rounds repeatedly hit the same exact spot. Also any ambient air exchange vent had to be offset baffled with steel plate. To prevent a bullet being fired into a vent, that could hit the mag’s content. Ocean going steel cargo containers with plywood lining inside fit the ticket back then, but not sure now.

Those are still the regs for a type 1 mag, which is used for storing HE. It is an entirely different story for a type 4 used in storing low explosives (fireworks, and under 10 lbs of flash fall into this category). The exact required specifications for a type 4 magazine are in my original post, as copied out of the orange book.

[oldguy]

The freezer idea has some merit but the 1/4" steel around the lock that is hooded becomes the real sticky part to the design. That is one reason why the job boxes are so popular, you can just weld a 1/4" thick sheet over the hood and be done with it.

 

It would not be a big chore for anyone who welds to fabricate a 1/4 inch thick steel hood with threaded rod or bolts welded to the back of the hood.

Then simply drill holes through the freezer wall, insert the hood & use washers & nuts to secure the hood in place from the inside.

Not that I would go to that trouble. But, its a differant story if you must pass an inspection.

[Mumbles]

Well, clearly finding the minimum metal thickness for a fabricated metal structure is step one. I honestly wouldn't be surprised if it is the same 1/4" required for the hoods.

[oldguy]

Well, clearly finding the minimum metal thickness for a fabricated metal structure is step one. I honestly wouldn't be surprised if it is the same 1/4" required for the hoods.

 

I have seen a lot of mag's & job boxes over the years & never seen a single one that was all constructed of 1/4 inch steel.

The 1/4 inch steel hood over a lock is to provide double protection over the lock. So it cannot easily broken or cut off.

I doubt a #4 mag would require overall 1/4 inch steel. That would be a heavy & costly unit.

[dagabu]

I don't have the thread in front of me but I seem to recall that the walls were only 1/2" thick wood (or material) with metal cladding, there was no minimum thickness of metal (I think).

[Peret]

To me, the regulations don't appear to make a great deal of sense. They're very specific about the locks, presumably intended to foil a robber with a whole uninterrupted night or weekend to work on getting the door open, but less concerned about the rest of it. Masonry walls can be opened in a few seconds with a pickup truck. You can go through the wall of a shipping container in minutes with a grinder. Who would waste time trying to pick a lock?

[cplmac]

A type 4 mag requires 12 guage steel, which is a very common thickness for toolboxes etc. It's .1046" thick. You need to have your magazine certified by the state before the ATF will certify it so start by contacting your state DNR (department of natural resources), it's probably going to fall under the department of mines and minerals. I'm not sure how well you would be able to weld the lock hoods to the air tank metal, or even if the air tank is at least 12 guage. Usually the biggest issue with magazine certification is distances, which will dictate whether or not you can have a magazine and if so how much can be stored in it. Type 4 mags have much lower distance requirements than type 2 or type 1 mags. And mumbles you are right, magazines are not at all designed to keep an explosion in but strictly to keep bullets, fire and people out. If the air tank metal is thick enough you should be fine.

[oldguy]

Depending on where a type 1 or 2 mag is situated. Some have to be far more blast resistant than others. If it is situated fairly near any public road, public transport, railroad, airport or infrastructure like power lines, pipe lines, bridges etc. They have to be far more blast resistant than one 40 miles the other side on nowhere, or on land you own for as far as the eye can see in all directions.

 

A lot depends on city, county zoning, state & fed Reg’s. If for any reason your site requires a county “zoning” variance. That will involve public notice & public meetings. No one living nearby, no adjoining home or property owner, and every business nearby will come to those public meeting and all will give a loud thumbs down. Nothing is usually easy if you are close to other peoples property, anything public, or of significant value.

 

Getting a site approved is one thing, getting the mag approved is another. Any registered Mag MUST be insured, or it will NEVER be permitted. First & foremost before you start any of that. Have a talk with your insurance agent. Because any class 1 or 2 mag rates (unless you own all the land around it for a mile or 2 each way) will make you almost faint in disbelief at the rate they quote you.

 

 

[cplmac]

None of our mags are insured, and we have 3 one type IV and two type I and II. That is probably something that may vary from state to state. Edited March 2, 2011 by cplmac

[oldguy]

None of our mags are insured, and we have 3 one type IV and two type I and II. That is probably something that may vary from state to state.

 

I am amazed you were not required to produce a “Certificate of Insurance”.

 

Must be an oversight in your State law.

 

Consider yourself lucky, not many are that explosives friendly.

 

http://www.atf.gov/explosives/how-to/explosive-storage-requirements.html

 

[NightHawkInLight]

Where on that page are you seeing insurance requirements? I have found no mention of insurance in any of the ATF regulation. In fact the word insurance isn't even mentioned once in the orange book, neither in the book itself, or in the questions and answers section.

 

I imagine all the magazines you have used in the past have been for commercial use, and likely became involved in your business insurance. I have heard plenty of cases where insurance was demanded before a township would issue a shoot permit, but I don't recall anyone having trouble with insurance for a magazine, particularly one only approved for low explosives.

 

Thanks for your input cplmac. I'll have to check how thick the wall of a compressor tank is.

 

Fortunately I have plenty of space for a type 4 mag containing 0 - 1,000 lbs, which only requires a 75ft radius from occupied structures and roads.