The .6.17 mm (.243) Lazzeroni Spitfire was designed in 1997 by Lazzeroni Arms Inc. of Tuscon, Arizona. The company was founded by John Lazzeroni and offers proprietary rifles and ammunition for sale on the commercial market. They currently have designs for 14 calibers and a variety of rifles for sale on the commercial market.
The ballistic performances based off four hand loading grain types for maximum loads on the 6.17mm Lazzeroni Spitfire on muzzle velocity is 4,206 ft/s (55 gr Noser w/55 gr Hodgdon Varget), 3,806 ft/s (70 gr Nosler w/49 gr Hodgdon Varget), 3,460 ft/s (85 gr w/46 gr Hodgdon Varget), and 3,269 ft/s (100 gr w/ 51 gr Hodgon H4350 Extreme). This is based off a 24 inch test rifle with a 10 inch twist.