40-70

The Bofors 40 mm Automatic Gun L/70, (Bofors 40 mm L/70, Bofors 40 mm/70, Bofors 40/70 and the like), is a multi-purpose autocannon developed by the Swedish arms manufacturer AB Bofors (today BAE Systems Bofors) during the second half of the 1940s as a modern replacement for their extremely successful World War II-era Bofors 40 mm L/60 gun-design. It was initially intended as a dedicated anti-aircraft weapon, being sold as Bofors 40 mm Automatic A.A. Gun L/70, but has since its conception been redeveloped into a dedicated multi-purpose weapon capable of firing both sabot projectiles and programmable ammunition. The Bofors 40 mm L/70 design never achieved the same popularity and historical status as the original L/60 design but has still seen great export and popularity to this day, having been adopted by around 40 different nations and even being accepted as NATO-standard in November 1953. It is still being produced and sold (since March 2005 by BAE Systems AB), and several variants exist for both field and naval applications. A notable variant is the Bofors 40/70B "light armored vehicle variant" which is in use on the Swedish Strf 9040 and Korean K21 infantry fighting vehicles.
The Bofors 40 mm L/70, like most Bofors autocannons, is based on the same core action as the original Bofors 40 mm Automatic Gun L/60, basically being a fire on closing, self-ejecting gun with a recoil-operated autoloader in the same receiver, and thus looks visually similar. Despite this, the Bofors 40 mm L/70 is a separate design with a number of major changes compared to its predecessor. The most superficial changes are the longer L/70 barrel, double cooling vents on the jacket and the fact that the weapon comes chambered for a more powerful 40×365mmR cartridge (vs 40×311mmR for the Bofors 40 mm L/60). Most importantly however is the new ejection system which ejects the empty cartridge cases out from the opposite side to the feed, compared to the ejecting system on the 40 mm L/60 which ejects the cases straight out the back of the gun. This system change almost doubled the mechanical rate of fire from the previous system.
In spite of the Bofors 40 mm L/70 being a separate development to the older Bofors 40 mm L/60 design, the similarities and success between the two guns has caused them both to be widely known simply as "the Bofors" or the "Bofors 40 mm gun", which at times causes the guns to be confused as one and the same weapon.

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