Ricochet

A ricochet is a rebound, bounce or skip off a surface, particularly in the case of a projectile. The possibility of ricochet is one of the reasons for the common firearms safety rule "Be sure of your target—and of what is beyond it."

Variables

The likelihood of ricochet is dependent on many factors, including bullet shape, velocity (and distance), target material and the angle of incidence.

Bullet

Bullet construction has a major factor in determining both the likelihood of ricochet as well as where the bullet will travel afterward. Hard bullets have a greater tendency to penetrate than softer ones. Bullets that break up, such as varmint hunting bullets, have a low risk of ricochet. This is one of the reasons the newer .17 HMR round with its frangible bullet has gained popularity against the older non-fragmenting .22 WMR, because of the lower chance of ricochet.

Velocity

Ricochets are often more common with low power calibers such as .22 or .177 calibre, which can have trouble penetrating some materials, although a ricochet can occur with any caliber. Higher velocity projectiles have a tendency to either penetrate the target, and/or to break-up on contact with it.

Target material

Bullets are more likely to ricochet off flat, hard surfaces such as concrete or steel, however a ricochet can occur on almost any surface including grassed soil, given a flat enough angle when hit. Materials that are soft, give easily, or can absorb the impact have a lower incidence of ricochet, for example sand. Though it may not be obvious, bullets easily ricochet off water.

Angle

The angle of departure, both vertically and horizontally, is difficult to calculate or predict due to the many variables involved, not the least of which is deformation of the bullet caused by its impact with the surface it strikes. Ricochets will almost always continue on a somewhat diagonal trajectory to their original trajectory, unless it is against a flat surface perpendicular to the angle of incidence (or approach), in which case, it will reflect at an angle dependent on the other variables involved in the ricochet incident.

Dangers

Ricochets are a common danger of shooting because after bouncing off an object the bullet that ricochets poses an 'unpredictable' and serious danger to bystanders, animals, objects, or even the person who fired the shot. When the deformed projectile does hit a bystander or another target it can become very dangerous. Instead of cleanly traveling through the "body/object", the bullet can behave more like a hollow point bullet, causing a larger wound cavity, or even fragmenting and causing multiple wound channels.

In rare cases, ricochets can return to the shooter. This occurs when the object struck possesses enough resistance to withstand the impact of the bullet, and whose surface is perpendicular to the shooter. Some bullets are designed to deform at the nose, which is the main reason for the bullet ricocheting at such an extreme angle and returning in the shooter's direction.

See also

• Gun safety
• Ballistics

External links

• "Ricochet Off Glass" at National Crime Investigation and Training web site
• Video of fake Bullet Ricochet on Shooter

Recommended reading

• Federal Bureau of Investigation, "Bouncing Bullets," FBI Law Enforcement Bulletin, Vol. 38, Oct. 1969, pp. 1-9.
• Garrison, D.H., "Crown & Bank: Road Structure as it Affects Bullet Path Angles in Vehicle Shootings," AFTE Journal, Vol 30, No. 1, Winter 1998, pp. 89-93.
• Gold, R.E. and Schecter, B., "Ricochet Dynamics for the Nine-Millimetre Parabellum Bullet," Journal of Forensic Sciences, Vol. 37, No. 1, Jan. 1992, pp. 90-98.
• Haag, L.C., "Bullet Ricochet: An Imperical [sic] Study and a Device for Measuring Ricochet Angle," AFTE Journal, Vol. 7, No. 3, Dec. 1975, pp. 44-51.
• Hartline, P., Abraham, G. and Rowe, W.F., "A Study of Shotgun Ricochet from Steel Surfaces," Journal of Forensic Sciences, Vol. 27, No. 3, July 1982, pp. 506-512.
• Jordan, G.E., Bratton, D.D., Donahue, H.C.H. and Rowe, W.F., "Bullet Ricochet from Gypsum Wallboard," Journal of Forensic Sciences, JFSCA, Vol. 33, No. 6, Nov. 1988, pp. 1477-1482.
• McConnell, M.P., Triplett, G.M. and Rowe, W.F., "A Study of Shotgun Pellet Ricochet," Journal of Forensic Sciences, Vol. 26, No. 4, Oct. 1981, pp. 699-709.
• Rathman, G.A., "Bullet Ricochet and Associated Phenomena," AFTE Journal, Vol. 19, No. 4, Oct. 1987, pp. 374-381.