Why bullpups?

[SHORT-N-SASSY]

Tony has recently updated his article.

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[COLOR="blue"]Some final thoughts: the current interest in the possibility of a new general-purpose long-range cartridge to replace both the 5.56x45 and the 7.62x51 enhances the case for the bullpup solution. It could be argued that a 7.62mm rifle, being intended primarily for long-range fire, need not be compact, while a 5.56mm carbine, being optimised for relatively short ranges, is not greatly disadvantaged by a short barrel. However, a general-purpose rifle in a general-purpose calibre would need to be short for urban fighting but have a long barrel for optimum long-range ballistics. This can only be achieved in one gun by using the bullpup layout, unless soldiers are to be expected to carry two barrels of different lengths and keep swapping them as the range changes.

Furthermore, the design of a new general-purpose calibre could be influenced by which layout is chosen, if the bullpup's compactness is used to provide a longer barrel rather than a shorter gun. This is because there is an inverse relationship between the barrel length and the size and power of the cartridge required to achieve any given ballistics: other things being equal, the shorter the barrel, the more powerful the cartridge needs to be. This is illustrated by the two notional 6.5mm cartridges shown below (courtesy of Joe Smith). Both of them are designed to develop a muzzle energy of 2,500 J (1,850 ft lbs): the shorter cartridge (basically the 6.5mm Grendel) will achieve this from a 24" (c.600mm) barrel; the larger cartridge, around 9mm longer, is required to accommodate enough propellant to achieve the same muzzle energy from a 16 inch (c.400mm) barrel.



To put it another way, there is a choice between two rifles of the same overall length and ballistic performance: a bullpup using the short cartridge, or a traditional carbine using the long cartridge. The bullpup solution allows the selection of lighter ammunition, developing less recoil, and with a much smaller firing signature in terms of muzzle flash and blast, thereby needing a significantly smaller and lighter suppressor to achieve any given decibel level.[/COLOR]

http://quarryhs.co.uk/bullpups.htm

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[SIZE="3"]I think it's ironic that while, on another Thread (http://www.65grendel.com/forum/showthrea...post102073), we're discussing Load testing for the 6.5mm Grendel bolt-action CZ527 (effectively, removing the constraints imposed on the Grendel-AR-15 marriage, by the laws governing Bolt Thrust), here, the emphasis is on the benefits of the shorter Bullpup configuration, using a longer (24") barrel (". . . allows the selection of lighter ammunition, developing less recoil, and with a much smaller firing signature in terms of muzzle flash and blast . . ."), compared to the traditional longer configuration, using a shorter (16") barrel ---



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