This article is from the Model Rockets FAQ, by Wolfram von Kiparski with numerous contributions by others.
NOTE: As of 1997, the BATF will be formally clarifying their
interpretation of what high power rocket motors require a Federal
Low Explosives Users Permit (LEUP). At the time that this is written
(Jan. 9, 1997) it appears that reloadable motor propellant segments
less than 62.5 grams in mass will require a LEUP if their intended use
is to assemble a motor that has more than 62.5 grams of propellant.
Furthermore, LEUP fees may be raised. At the time of this writing, these
changes are not yet in effect. The National Association of Rocketry and
Tripoli Rocketry Association are working together to see what can be done
to protect the interests of high power rocketry enthusiasts, and will
be keeping their members informed of the latest developments.
The following are excerpts from a joint communique issued by the
High Power Rocket Manufacturers and Dealers Association and the Tripoli
Rocketry Association to the high-power rocket community on 25 April 1994.
It was posted to CompuServe by Michael Platt, president of the HPRMDA.
[Based on informal clarifications from the BATF, it is our belief that:]
(a) single-use model rocket motors containing no more than 62.5 grams of
propellant are exempt from Federal licensing and storage requirements;
(b) reloadable rocket motor products are also exempt from Federal licensing
and storage requirements, provided that the mass of each propellant grain is
no more than 62.5 grams, and has received a DOT shipping designation as
Explosive 1.4, but may not be made available to children;
(c) any single-use motor containing propellant mass greater than 62.5 grams,
or any reloadable rocket motor product containing a propellant grain which
weighs more than 62.5 grams, is subject to Federal licensing and storage
Users (e.g. consumers, flyers) of high-power rocket motors and reload kits
as described in item (c) above, are subject to Federal, and possibly state
and local, permit requirements for the purchase and storage of explosives.
On the Federal level, this involves obtaining an explosive user permit from
BATF, at a cost of $20 for the first year, and $10 for each subsequent
three-year period. An important exception to the Federal requirement for a
user permit is if the user were to purchase a motor or reload kit in his
state of residence as defined by BATF, and either (a) use the motor or
reload kit at the site of purchase (e.g. a launch), or (b) transport it to
an approved storage facility located within the boundaries of said state.
Everyone--manufacturers, dealers (distributors), users--who stores (as
defined by the BATF) a high-power rocket motor or reload kit as described
in item (c) above is subject to Federal, and possibly state and local,
requirements for the storage of explosives. All storage of a high-power
rocket motor or reload kit must be in accordance with Federal explosive
storage requirements, even if a Federal license/permit is not required for
purchase. There are no exceptions to this rule.
A document with questions and answers about the BATF and rocketry is
available at the sunsite archive:
Instructions for filling out a LEUP are available on the Rocket Science