Bureau of Alcohol, Tobacco, Firearms, and Explosives

Rocket motors

The ATF has exempted some motors/reload kits with no more than 62.5 grams of propellant. The exemption is:

27 CFR 555.141(a)(10)

Model rocket motors that meet all of the following criteria--

(i) Consist of ammonium perchlorate composite propellant, black powder, or other similar low explosives;

(ii) Contain no more than 62.5 grams of total propellant weight; and

(iii) Are designed as single-use motors or as reload kits capable of reloading no more than 62.5 grams of propellant into a reusable motor casing.

Because of the recent victory in the NAR/TRA lawsuit against the ATF, the ATF's decision to regulate Ammonium Perchlorate Composite Propellant (APCP) as an explosive has been vacated. As a result you can purchase any APCP motor or reload kit without an ATF permit. The same is mostly true for BP motors. Although BP motors with more than 62.5 grams of propellant are regulated there are none currently on the market.

Igniters and BP

Although nearly all rocket motors are unregulated, some items commonly used in the hobby are regulated. These include igniters (this includes electric matches), igniter cord (the now very hard to find thermalite), and BP.

Igniters are one of the items listed in the statutory definition of explosives and as such they are regulated. The only thing that can change that is an act of Congress. But the law fails to define just what an igniter is. The result is that some igniters are regulated (Quickburst found this out the hard way.), and some are not. The Estes Solar igniter being the prime example of an igniter that the ATF does not regulate. The ATF has never provided clear guidance on how to determine if your igniter is regulated.

Although igniter cord like Thermalite is used less and less, mainly due to it not being manufactured anymore, it is a very handy item to have at times. At one time Aerotech reload kits came with a short piece of Thermalite to use as a booster for the included Copperhead igniter.

Black Powder (BP) is the most commonly used material in ejection charges. It is very handy to have around but it is regulated. In practice it is not difficult to purchase as it is exempt for use in antique firearms and it is usually sold with no questions asked. On the other hand, if you run afoul of the law with a can of BP in your car you could be charged with illegal transport of explosives. Federal law prohibits transportation of explosives by anyone other than an ATF permittee/licensee. (With an exception for commercial transport via common carriers.)

So although motors are not regulated it is still handy to have a permit.

The Law and Regulations

The ATF's authority to regulate explosives derives from the Organized Crime Control Act of 1970. You can read that as part of the ATF's Orange Book but be advised that this document is only published every 10 years or so and as a result is almost always out of date. To read the explosives laws as they currently exist you need to go somewhere that updates a little more frequently than once a decade. I use the Cornell Law School web pages as they seem to update reasonably often. What you want is Title 18, Part I, Chapter 40.

Notice that violations of the explosives laws are punishable by fines and up to ten years in prison.

The Orange Book also contains a copy of the ATF's regulations which are derived from the explosives laws. As these change more frequently than the law, the Orange Book is once again a monument to ancient history. Instead use the Government Printing Office web site which gets updated once a year. You want the most recent version of Title 27, part 555.

Just to be safe, you should also search the Federal Register just to make sure no new rules have taken effect since the GPO pages were last updated. A search on "commerce in explosives" usually does the trick.

Explosives Permit

First of all, do not apply for a "Limited" permit. You will trade the savings of a few dollars for limits on the number of purchases you can make per year, only operating within your state, and the hassle of renewing every year. This is a case where being cheap is stupid. The difference in cost for the first three years is $100 vs. $49 but after that the difference is between $50 and $36 every three years.

In order to get a permit you must of course apply for one. While you can download a copy of the permit application from the ATF web site, you also need a special fingerprint card. Although the only thing special about it is the ATF stamp. You will have to contact the Explosives Licensing Center.

While the distinction between explosive classes for permits went away in 2005, the ATF has not updated their form so you should continue to check the box for a Type 34, User of Low Explosives, permit. What you should get is a User of Explosives Permit. While you can of course use this to pick up a case of dynamite, you are required to store it properly and a Type 4 magazine just doesn't cut it.

When you apply for a permit, your biggest question is going to be what to do about storage. You have two basic options: 1) get a Type 4 magazine or, 2) use someone else's magazine.

One of the interesting features of an indoor Type 4 magazine is the table of distances does not apply. This is very handy given the small lot sizes of most homes built these days. If you have a permanent shed (concrete foundation or footings would be best) you can put the magazine there. The ATF is usually quite particular about the shed and usually want something that can't be easily moved.

If a shed isn't an option, you can apply for a variance for storage in an attached garage. This is the route I went. Note that the ATF likes to attach various conditions to the variance. The most common being separate storage of "igniters".

Note that there is nothing in the regulations requiring separate storage for igniters (there is such a requirement for detonators). Which reminds me. Read the law and regulations carefully before your interview with the ATF. You want to be in a position to know when they are making stuff up. As tempting as it may be, don't call them idiots. Simply act puzzled and ask for them to point out the item in question in the regulations. When that fails, request that they provide a written reference to substantiate their claim. If you don't take this step you run the risk of having an agent steamroll you with bizarre and idiotic requirements.

Another thing to keep in mind is that the Paperwork Reduction Act imposes certain requirements on "information collections". The main one is that the agency is required to get the collection reviewed and approved by the Office of Management and Budget. The form must display a valid OMB number and you can visit the Reginfo website to view approved collections.

The ATF has recently been using an unapproved collection. If they do this, point out the federal law prohibits such use and also prohibits (44 USC 3512) any penalty if you refuse to go along with it.

If you don't get your own magazine, you will have to arrange for storage with another permittee. A simple verbal agreement will not do as you will have to document this for the ATF. A signed letter from the other permittee along with his address and permit number should do the trick. It is almost certain that the ATF will followup and call this person so don't be cute.

When you ask the ATF for an application they will include a lot of stuff in the packet, some of which you can ignore.

One of the things you can ignore has to do with pollution and specifically 33 USC 1341. Since you will not be doing anything that might pollute a "navigable waterway", you don't have to mess with this.

The ATF will include copies of the Employee Possessor Questionnaire. You are not an employee and all of your information is on the main form. If you decide to include a spouse on your permit, they will be a responsible person. No EPQ required but fingerprints and a photograph are along with answering the questions on the form.

You might have someone in the ATF insist that everyone must fill out an EPQ but they are incorrect. The regulations at 27 CFR 555.45 do say "The Chief, Firearms and Explosives Licensing Center, will not approve an application postmarked on or after March 20, 2003, unless it is submitted with a Responsible Person Questionnaire, ATF Form 5400.28" (This is the form number for the EPQ.) However this text is in section (a) which is specifically limited to "Licenses issued prior to May 24, 2003".

The ATF may have wanted for everyone to fill out the form but the published regulations do not require it and they have had a long time to fix the problem if they really wanted to. They might eventually as they still need to publish the final rules resulting from the Safe Explosives Act. We will have to get along with their "interim final" rules until then.

Once the ATF receives your application, they are required by law to either grant or deny it within 90 days. They have demonstrated that they frequently do no meet this requirement. Alas there is no penalty to the ATF for breaking this law. The only thing you can do is follow up with calls to your local ATF office and the ATF's Explosives Licensing Center. When that fails, try writing to your Congressman or Senator. This worked wonders for me during my 2004 renewal.

Find the web sites for your Congress critters and look for a link for "Constituent Services". They all have them for the purpose of helping you deal with federal agencies.


You will have to renew your permit every three years. This should be simple but the ATF hasn't made it that way. The regulations require a specific form (ATF Form 5400.14/15 Part III) be used for renewal but it hasn't been available for a very long time. I attempted in 2006 to get a copy when I read a notice in the Federal Register stating that it was under review by the OMB. I got nothing. The last excuse I received in 2007 was that it was being revised.

I eventually filled out only part of the regular form as all of the detailed information was already on file and hadn't changed.


The biggest hassle involved with being a permittee is that you must maintain records. Look over the section of the regulations that explain this carefully as your records will be examined and this is the most likely area where you will get into trouble.

The records for a user permit are basically just acquisition and magazine. Whenever you acquire a regulated item you must record the required information. (See 27 CFR 555.125) Including the "marks of identification". It was a very long time before I discovered what this phrase meant as it isn't defined. I found it in the section of regulations for manufacturers and importers and marking, 555.109. It basically identifies the manufacturer, date, and location of manufacture.

You must record whenever you place something in your magazine and whenever you remove it. Very simple actually. Note that as a user you are not required to record how you use or dispose of items with one exception. If you transfer or sell "excess" stock to another permittee/licensee, you must record that. It is in the regulations.


Here we go again. October 2009 edition.

There has been a bit of a kerfuffle lately over igniters. It seems that some ATF agents told a vendor that Copperhead, First Fire, and First Fire Jr. igniters are regulated and must be logged, stored, and otherwise treated just like any other regulated explosive. Which is a change. The reasoning given for this decision was that they are classified by DOT as UN 0454, Igniters. This might be the result of delusional behavior by local ATF agents or part of an organized effort by the ATF as a whole.

The first problem with this is that it represents a change in behavior on the part of the ATF without appropriate notice and comment rule making. They might claim that by law all igniters are regulated but the fact is that many have not been for a very long time.

In order to be consistent they must also regulate Estes igniters. While those have a UN0432, articles pyrotechnic classification, they are still igniters just as much as the Aerotech products. If ATF regulates one and not the other then they are being arbitrary and capricious.


One of the features of federal law is that it is highly compartmentalized. This allows for conflicting definitions to be used in different sections of the law. For example, tax law requires a $200 transfer tax be paid on the sale or transfer of every firearm. If the definition for firearm used in 18 USC Chapter 44 was used this would apply to everything. But instead a very specific definition in the tax law is used so it applies only to a small subset of what is normally considered to be firearms. Those definitions begin with the phrase: "For the purpose of this chapter". Which is 26 USC Chapter 53. This created the bizarre situation of the ATF having two distinct definitions for one word. This didn't seem to result in them requiring the tax be paid on hunting rifles so the ATF can make this sort of distinction when it wants to.

So the simple fact that the DOT classifies something as UN0454, Igniter has no bearing whatsoever on the regulation of that item by the ATF as an igniter. The problem is that federal law lists igniters as an example of explosives that are to be regulated but then fails to define what is meant by that term. The ATF has never felt the need to correct this problem by publishing a definition on its own at 27 CFR Part 555. So we now have the problem where ATF agents in the field are making it up.

Consistency among the various federal agencies is a good thing but this principle means that they should keep their regulations consistent. It does not mean that one agency gets to avoid defining some term. Instead they should make sure that the definition the publish, so far as is possible, is consistent between agencies.

What is meant by the term igniter is by no means restricted to items using explosive materials. Jet engines have igniters. What Americans call a spark plug the British call an igniter. So it should be obvious that there are things called igniters that are not regulated as explosives and some that are. But the ATF has failed to provide any written guidance. In the absense of a clear criteria you must instead ask the ATF. Which opens the door to varying and inconsistent (even within the ATF) decisions.

Igniter Exemption

The only explanation I have ever found as to what criteria the ATF used to distinguish exempt from non-exempt igniters appears in a NAR BoT meeting summary from 1997.

While many HPR issues were created by the BATF's announcement, Pat Miller pointed out the extraordinary effort to which BATF staffer worked to avoid any adverse impacts on the model rocket hobby. He reported BATF would leave unregulated any igniters with 35-50mg of pyrogen each. That amount would be determined by averaging over 30 igniters. AP-based single-use and reloadable motors with less than 62.5 grams total propellant weight remain unregulated.

The current MSDS for Aerotech igniters is less informative than an older version which says:

Copperhead and FirstFire igniters consist of a copper/Mylar/copper-based flex circuit material of various shapes and sizes or a two-conductor lead wire coated with up to 50 milligrams of flammable material which consists primarily of carbon black, carbon fibers, ammonium or potassium perchlorate (NH4ClO4 or KCLO4) and aluminum dispersed in a nitrocellulose-based binder.

Based on those two bits of information you would have to conclude that Aerotech igniters are exempt. But the ATF has never been a slave to consistency.

One serious problem with the 50mg limit is that the ATF never clarified this position by issuing a formal ruling. So they can deny it ever happened but they cannot deny that they haven't been regulating a lot of igniters. The apparent change to using the DOT classification is at odds with this previous position and this change requires notice and comment rulemaking. The ATF can make this change but they must follow the procedures set down in the Administrative Procedures Act. If sued, they will lose. As evidence for that opinion I submit the following from the March 2004 court opinion:

The Court finds that the variance between the pronouncements in the ATF's April 20, 1994 and December 22, 2000 letters, with respect to the applicability of the PAD exemption to sport model rockets, squarely fits into the scenario discussed by the District of Columbia Circuit in Alaska Professional. Here too, an agency sought to reverse the applicability of an exemption without notice and comment. Thus, before the ATF could altered its earlier interpretation of the applicability of the PAD exemption, it was required to undertake notice-and-comment rulemaking as required by the APA and the OCCA. Because the ATF failed to do so, the Court concludes that its December 22, 2000 pronouncement regarding the applicability of the PAD exemption to sport model rockets was not in compliance with the OCCA and the APA.

Regulation of BP Substitutes?

In the aftermath of the 2013 Boston Bombing, Senator Frank Lautenberg introduced a bill to increase regulation of black powder and other things. The proposed bill makes for tedious reading since it consists of various deletions, insertions, and substitutions to existing law. So you have to read the existing version at the same time to really get a sense of the changes.

The bill amends various parts of the law and here is an overview:

Section 841 - definitions

Adds smokeless powder and black powder substitutes to the statutory definition of explosives.

Removes "in the business of" from the definition of a manufacturer. This will cause great heartburn in some areas. It means that you would no longer be able to make explosives (fireworks mainly) for your own use without an ATF license.

Section 842 - Unlawful Acts

Adds some new ways to be disqualified from ever touching explosives. Including a misdemeanor conviction of domestic violence. (currently it requires any felony to do the trick)

Plus a restraining order.

Section 843 - Permits

This is harder to follow than usual but it appears to remove the 6 transactions per year limitation on holders of limited permits in the case of black powder etc.

Adds language to permit the denial or revocation of a license if you are suspected of being a terrorist. Or supporting them. Or maybe just being seen in a photograph with one.

Even worse, it allows the ATF to withhold whatever information it was that they used to reach that conclusion. This pretty much eviscerates the appeals process.

Even more worse it says that the ATF doesn't even have to tell a judge what this information is. Just summaries or redacted versions. It is almost as if someone thinks that the federal courts are incapable of handling this sort of information. Except that they are. The only instance that I am aware of where this kind of information was leaked, it was leaked by the prosecutor.

Section 845 - Exceptions:

This is the meat of the bill as it removes the exception for black powder. A minor quibble is that the deletion is ill formed. It deletes "black powder..." but leaves the words "commercially manufactured" which precedes it. I ain't no English major, but I think that the commercially manufactured bit applies only to black powder and to none of the other items listed.

It also explicitly excludes black powder substitutes and smokeless powder from the the small arms ammunition and components exemption.


So in order to purchase any of these you would first have to get a Federal Explosives License. (FEL) Plus removing these exceptions also makes these materials subject to the storage requirements as published at 27 CFR Part 555. It also makes transportation without a permit a crime.

This will be wildly unpopular with the reloading crowd. The NRA and their minions in the Senate will see to it that this dies. Either quietly in committee or noisily on the Senate floor.

Of course this bill ignores the little detail that BP was already apparently so hard to acquire that the Boston Bombers simply purchased commercial consumer fireworks. There is nothing in this bill that would change that. It also wouldn't change the easy availability of many different materials that can be used to make explosives.

The particular bit of this bill that I personally hate is the part about denying a permit simply on the basis of suspicion. At least Congress hasn't forbidden the ATF from spending any money on applications for relief from disabilities (which is how you would have to appeal) under the explosives law like they have for firearms.