Tannerite is the trademark for a patented ammonium nitrate/aluminum powder based binary explosive used primarily as a target for firearms practice. Tannerite is unique in that it is exceptionally stable when subjected to less severe forces such as a hammer blow or being dropped. It is supplied as two powders which are combined to produce the explosive.
Tannerite detonations occur at a very high velocity, producing a large explosion and cloud. It is marketed as a target designator. Useful for persons who are firing at long ranges; in this scenario, a long-range rifle shooter emplaces targets, retreats to his firing position, and fires. The shooter does not wish to have to walk down range to see if he has a hit—the Tannerite will detonate and serve as an indicator.
Tannerite is used by shooting clubs to provide explosions for their participants in large-scale weaponry demonstrations or other events. Ordinarily, firing rifle caliber machine guns and long arms will not produce much more than sound upon impact of the round on the target. With reactive targets, these shooting clubs can provide a movie-like experience such as exploding cars.
The manufacturer recommends using no more than 0.5-pound (0.23 kg) of the mixed composition at once, for safety reasons.
It also has uses as a general explosive that, prior to mixing, can be sold, transported, and stored in the United States without any special permits.
Manufacture and sale 
Tannerite consists of two components: a catalyst or sensitizer and a bulk material or oxidizer. The oxidizer is a mixture of 85% 200-mesh ammonium nitrate and 0–15% ammonium perchlorate, while the catalyst is a mixture of 90% 600-mesh dark flake aluminium powder, 5% 325-mesh titanium sponge and 5% 200-mesh zirconium hydroxide. Simpler mixtures of ammonium nitrate and aluminium powder often named as ammonal are also known to work.
In the United States, ATF regulations allow the two components to be legally purchased, since neither one is an explosive by itself. However, the mixture is an explosive once mixed, and cannot be transported without following strict regulations including insurance, packaging, and signage on the vehicle. Various regulations also govern the storage of mixed Tannerite.
A Maryland law intended specifically to ban the sale or ownership of Tannerite became effective on October 1, 2012, and expanded the definition of an explosive to include, in addition to "bombs and destructive devices designed to operate by chemical, mechanical, or explosive action", "two or more components that are advertised and sold together with instructions on how to combine the components to create an explosive".
In the news 
A Minnesotan man was fined $2,583 and sentenced to three years' probation on charges of detonating an explosive device and unlawful possession of components for explosives after he detonated 100 lb (45 kg) of Tannerite inside the bed of a dump truck by shooting it with a rifle chambered in .50 BMG from 300 yards (270 m) away on January 14, 2008 in Red Wing, Minnesota. The man was on probation when he mixed and shot the Tannerite and was not allowed to possess firearms or explosives.  The blast could be felt at Prairie Island Nuclear Power Plant (roughly 5 miles away).
A 20-year-old man in Busti, New York stated that he shot 18 pounds of Tannerite resulting in an explosion that sent a "loud boom" through the area and extended as far south as Pennsylvania, at least 3 miles away. This explosive noise caused numerous phone calls to the Chautauqua County Sheriff's Office, the New York State Police, and other law enforcement in the area. 
- https://www.tannerite.com Tannerite Company (Pleasant Hill Oregon USA) website
- US patent 6848366, Tanner, Daniel Jeremy, "Binary exploding target, package process and product", issued 1 February 2005
- "Federal Explosives Law and Regulations, Questions and Answers". Bureau of Alcohol, Tobacco, Firearms and Explosives. November 2007. p. 4. Retrieved 11 March 2009.[dead link]
- Md. Code Ann., Public Safety § 11–101
- Maryland House Bill 875 (May 22, 2012)
- "Welch man gets probation for explosion". Rochester Post-Bulletin. 10 October 2009.
- "Blast near Red Wing brings felony charges" Hastings Star Gazette 16 January 2008 
- Barringer, Glen (15 January 2008). "State of Minnesota Criminal Complaint" (PDF). Retrieved 17 March 2009.
- "Big boom could land amateur bomb maker in huge trouble". KARE 11 News. 14 January 2008. Retrieved 19 January 2008.
- "Boom Caused By Shooting Explosives; Ban Considered In County" Post Journal 15 January 2013, By Eric Tichy, http://post-journal.com/page/content.detail/id/616223/Boom-Caused-By-Shooting-Explosives--Ban-Considered-In-County.html?nav=5192