Rifle barrel and method of determining rifling twist for very long range accuracy

A rifle having a rifled barrel and a cartridge having a bullet having a diameter, a length, a ballistic coefficient (BC), and a muzzle velocity (V1) greater than 1250 ft/sec are related to achieve accuracy at very long range in that the twist of the rifling is substantially equal to: 83.7 ÷ ( bullet...

Full description

Saved in:
Bibliographic Details
Main Author BARTOLI DAVID JOHN
Format Patent
LanguageEnglish
Published 28.09.2010
Subjects
BLASTING
FUNCTIONAL FEATURES OR DETAILS COMMON TO BOTH SMALLARMS ANDORDNANCE, e.g. CANNONS
HEATING
LIGHTING
MECHANICAL ENGINEERING
MOUNTINGS FOR SMALLARMS OR ORDNANCE
WEAPONS
Online AccessGet full text

Cover

More Information
Summary:A rifle having a rifled barrel and a cartridge having a bullet having a diameter, a length, a ballistic coefficient (BC), and a muzzle velocity (V1) greater than 1250 ft/sec are related to achieve accuracy at very long range in that the twist of the rifling is substantially equal to: 83.7 ÷ ( bullet ⁢ ⁢ ⁢ length × 2 ⁢ B ⁢ ⁢ C bullet ⁢ ⁢ diameter ) × bullet ⁢ ⁢ diameter × [ 1 + ( V 3 V 1 × 0.667 ) ] where: V2 is the entry speed for the transonic, i.e. 1,250 ft/sec., and V3 is V1 minus V2. A rifle barrel for receiving a bullet has rifling twist according to the relationship. A method uses the relationship to determine the rifling twist for a rifle barrel receiving a known bullet. Another method uses the relationship to design a cartridge for a known barrel rifling. The relationship is particularly applicable for bullets having a high BC, such as 0.325 or greater.
Bibliography:Application Number: US20070899647