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The International Confederation of Fullbore Rifle Associations (ICFRA) is the international association for the fullbore rifle shooting sports of target rifle ('TR') (called 'Palma' rifle in the US) and F-Class, which are long range competitions shot at distances between 300 and 900 meters or 300 to 1,000 yards depending on the range. [1]
Note: Use of this table for estimating bullet masses for historical large-bore rifles is limited, as this table assumes the use of round ball, rather than conical bullets; for example, a typical 4-bore rifle from circa 1880 used a 2,000-grain (4.57 oz; 129.60 g) bullet, or sometimes slightly heavier, rather than using a 4-ounce (110 g) round ...
Rock-quality designation (RQD) is a rough measure of the degree of jointing or fracture in a rock mass, measured as a percentage of the drill core in lengths of 10 cm or more.
The Barrett Optical Ranging System (BORS) was an integrated ballistics computer manufactured by Barrett Firearms that aids snipers and long-range marksmen in taking precise and accurate shots.
The name, derived from an old English practice of bore measurements in gun-making which refers to a nominally 4-gauge bore, that is, a bore diameter that would accommodate a pure lead round ball weighing 1 ⁄ 4 of a pound. This would imply a bore diameter of 1.052-inch (26.7 mm), however in practice the bore diameter varied greatly as, in ...
The bullet must tightly fit the bore to seal the high pressure of the burning gunpowder. This tight fit results in a large frictional force. The friction of the bullet in the bore does have a slight impact on the final velocity, but that is generally not much of a concern. Of greater concern is the heat that is generated due to the friction.
This method of bore finishing is better suited for bores with relatively low length-to-diameter ratios, usually less than 2:1. However, if there are cross-holes, or other interruptions in the bore, then a ratio greater than 2:1 is possible, because swarf and fluids may be expelled via these routes. This process is also not well suited for ...
A counterbore in a metal plate. In machining, a counterbore (symbol: ⌴) is a cylindrical flat-bottomed hole that enlarges another coaxial hole, or the tool used to create that feature.