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Freebore
In firearm, firearms, freebore (also free-bore, free bore, or throat) is the portion of the gun barrel between the chamber (firearms), chamber and the rifling, rifled section of the gun barrel#Bore, barrel bore. The freebore is located just forward of the chamber neck and is cylindrical in shape. The diameter of the freebore is larger than the groove diameter of the gun barrel bore so that no rifling is present and projectiles used in the firearm can accelerate through the freebore without resistance. Location and dimensions The Chamber (firearms), chamber is the rearmost portion of a firearm barrel that has been formed to accept a specific Cartridge (firearms), cartridge or shell. For firearms having a rifled barrel, the bullet typically extends forward from the leading edge of the cartridge case. The portion of the barrel forward of the chamber that provides clearance for the loaded bullet of a cartridge is known as the throat. The throat is composed of both a freebore and a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rifling
In firearms, rifling is machining helical grooves into the internal (bore) surface of a gun's barrel for the purpose of exerting torque and thus imparting a spin to a projectile around its longitudinal axis during shooting to stabilize the projectile longitudinally by conservation of angular momentum, improving its aerodynamic stability and accuracy over smoothbore designs. Rifling is characterized by its twist rate, which indicates the distance the rifling takes to complete one full revolution, such as "1 turn in 10 inches" (1:10 inches), "1 turn in 254 mm" ("1:254 mm" or "1:25.4 cm)", or the like. Normally, an experienced shooter can infer the units of measurement from the numbers alone. A shorter distance indicates a faster twist, meaning that for a given velocity the projectile will rotate at a higher spin rate. The combination of length, weight, and shape of a projectile determines the twist rate needed to gyroscopically stabilize it – barrel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
