There are also specialized bullets designed for use in long range precision target shooting with high-powered rifles; the designs vary somewhat from manufacturer to manufacturer. Research in the 1950s by the U.S. Air Force discovered that bullets are more stable in flight for longer distances and more resistant to crosswinds if the center of gravity is somewhat to the rear of the center of pressure. The MatchKing bullet (which is still in wide use and holds many records) is a hollow point design with a tiny aperture in the jacket at the point of the bullet and a hollow air space under the point of the bullet, where previous conventional bullets had a lead core that went all the way up to the point.