Hard to belive that the US '79 System has been around for half a century...........
"A NEW MILITARY SHOULDER WEAPON" - E.A. Harrison, AMERICAN RIFLEMAN, November 1960
40mm. Grenade Launcher XM79 fires a high-explosive shell up to about 400 meters. On October 19, 1960, the U.S. Army announced adoption of the 40mm Grenade, Launcher XM79. It fires a 6-oz. high-explosive shell at a muzzle velocity of about 250 f.p.s. and range up to 400 meters. Its designation will become M79 on formal standardization, which is expected to take place shortly. It was adopted to give the individual soldier a mortar-like capability between the distance the hand grenade can be be thrown and shortest range of the 81mm, mortar. The XM79 was the successful one of several competitive weapons developed for this requirement. It supplements the M14 rifle and M60 machine gun. The XM79 launcher was developed at Springfield Armory. The ammunition was developed under the supervision and with the help of Picatinny Arsenal, Crosley Corp., Division of Avco, at Connersville, Ind., was responsible for the loading and the complete round: Minneapolis-Honeywell, Minneapolis, Minn., for the fuze; Harvey Aluminum Co., Torrance, Calif., for the aluminum cartridge case; and the Chamberlain Corp., Waterloo, Iowa, for the fragmentation body.
The launcher is 28.6" long and barrel length is 14". Weight is 6 lbs. 11 ozs. loaded, 6 lbs. 2 ozs. empty. The weapon is thus quite short and handy. Its appearance is that of a short and fat hammerless single-barrel shotgun. The receiver or action body is of steel and heavily constricted. The hammerless action is automatically cocked on opening by a cocking lever under the barrel breech. Top lever and top safety are of shotgun form. The trigger guard is of winter type which can be swung away to either side on the release of a latch at its front end, so the launcher can be fired without taking off heavy gloves or mittens. Trigger pull is single stage, like that of a shotgun. The barrel is of aluminum alloy finished by anodizing. Rifling is 6 narrow lands .01" high, one turn in 48". Front sight is of conventional military pattern with guard wings like those of the carbine or M1 rifle. Rear sight is a large folding leaf, far up the barrel since high elevations are required. It is graduated to 400 meters and adjustable both for elevation and laterally. Quick elevation setting is done simply by pressing in the spring catches at ends of the elevation slide, and sliding it to the setting desired. Fine elevation setting is by screw and clicks, and similarly for lateral or 'windage' setting. The leaf is The XM79 is the first Army weapon with an all-aluminum barrel. Aluminum could be used because of the low velocity and low pressure at which the cartridge is fired. Stock and fore-end are black walnut. The stock is very straight, even slightly concave on top, partly to get the recoil in line with the buttplate and partly to make it easier to fire with high sight elevation. A rubber recoil pad is fitted. The piece points easily and naturally. It is also carried easily with sling. The whole design is very simple and strong. Operating parts, latches, and buttons offer large surfaces to the firer's fingers and work with great positiveness.
The 40mm cartridge is 3.9" long and weighs 9 oz. The caliber of 40 mm. is 1.575". There are only 365 milligrams (5.6 grs.) of propellant. This very small propelling charge and low density of loading caused difficulty in obtaining satisfactory uniformity of velocity, which was solved in an unusual way. The propelling charge is held in a cavity in the case head which has several holes through its walls. It confines the powder gases and forces them to pass out through the holes, controlling the burning. The shell fuze is a percussion type which initiates the burst on striking. As with all fuzes in our Services, great care is taken in the design to make it bore-safe (proof against premature functioning in the gun.) The fuze is armed after 30 yds. of flight.The launcher is fired from the usual rifling firing positions. It might be thought that the comparatively heavy projectile would the recoil unbearable. However, this is not so because of the low velocity. Computation shows the energy of free recoil to be about 21.5 ft.-lbs. or only slightly greater than that of the Service rifle, and it has been found in extensive testing that recoil presents no material difficulty. This new weapon can reach targets which hitherto have been safe in cover beyond hand grenade range. Parapets, shell holes, and concealment within a limited area are not protection against it. It can, as a striking example, even be used against an enemy around the corner of a wall, by firing against the ground or a wall beyond or in a house or bunker by firing straight into a window. The XM79 launcher is in pilot line production at Springfield Armory and the ammunition at Crosely Avco and Picatinny Arsenal. Distribution to troops will begin soon.
"A NEW MILITARY SHOULDER WEAPON" - E.A. Harrison, AMERICAN RIFLEMAN, November 1960
40mm. Grenade Launcher XM79 fires a high-explosive shell up to about 400 meters. On October 19, 1960, the U.S. Army announced adoption of the 40mm Grenade, Launcher XM79. It fires a 6-oz. high-explosive shell at a muzzle velocity of about 250 f.p.s. and range up to 400 meters. Its designation will become M79 on formal standardization, which is expected to take place shortly. It was adopted to give the individual soldier a mortar-like capability between the distance the hand grenade can be be thrown and shortest range of the 81mm, mortar. The XM79 was the successful one of several competitive weapons developed for this requirement. It supplements the M14 rifle and M60 machine gun. The XM79 launcher was developed at Springfield Armory. The ammunition was developed under the supervision and with the help of Picatinny Arsenal, Crosley Corp., Division of Avco, at Connersville, Ind., was responsible for the loading and the complete round: Minneapolis-Honeywell, Minneapolis, Minn., for the fuze; Harvey Aluminum Co., Torrance, Calif., for the aluminum cartridge case; and the Chamberlain Corp., Waterloo, Iowa, for the fragmentation body.
The launcher is 28.6" long and barrel length is 14". Weight is 6 lbs. 11 ozs. loaded, 6 lbs. 2 ozs. empty. The weapon is thus quite short and handy. Its appearance is that of a short and fat hammerless single-barrel shotgun. The receiver or action body is of steel and heavily constricted. The hammerless action is automatically cocked on opening by a cocking lever under the barrel breech. Top lever and top safety are of shotgun form. The trigger guard is of winter type which can be swung away to either side on the release of a latch at its front end, so the launcher can be fired without taking off heavy gloves or mittens. Trigger pull is single stage, like that of a shotgun. The barrel is of aluminum alloy finished by anodizing. Rifling is 6 narrow lands .01" high, one turn in 48". Front sight is of conventional military pattern with guard wings like those of the carbine or M1 rifle. Rear sight is a large folding leaf, far up the barrel since high elevations are required. It is graduated to 400 meters and adjustable both for elevation and laterally. Quick elevation setting is done simply by pressing in the spring catches at ends of the elevation slide, and sliding it to the setting desired. Fine elevation setting is by screw and clicks, and similarly for lateral or 'windage' setting. The leaf is The XM79 is the first Army weapon with an all-aluminum barrel. Aluminum could be used because of the low velocity and low pressure at which the cartridge is fired. Stock and fore-end are black walnut. The stock is very straight, even slightly concave on top, partly to get the recoil in line with the buttplate and partly to make it easier to fire with high sight elevation. A rubber recoil pad is fitted. The piece points easily and naturally. It is also carried easily with sling. The whole design is very simple and strong. Operating parts, latches, and buttons offer large surfaces to the firer's fingers and work with great positiveness.
The 40mm cartridge is 3.9" long and weighs 9 oz. The caliber of 40 mm. is 1.575". There are only 365 milligrams (5.6 grs.) of propellant. This very small propelling charge and low density of loading caused difficulty in obtaining satisfactory uniformity of velocity, which was solved in an unusual way. The propelling charge is held in a cavity in the case head which has several holes through its walls. It confines the powder gases and forces them to pass out through the holes, controlling the burning. The shell fuze is a percussion type which initiates the burst on striking. As with all fuzes in our Services, great care is taken in the design to make it bore-safe (proof against premature functioning in the gun.) The fuze is armed after 30 yds. of flight.The launcher is fired from the usual rifling firing positions. It might be thought that the comparatively heavy projectile would the recoil unbearable. However, this is not so because of the low velocity. Computation shows the energy of free recoil to be about 21.5 ft.-lbs. or only slightly greater than that of the Service rifle, and it has been found in extensive testing that recoil presents no material difficulty. This new weapon can reach targets which hitherto have been safe in cover beyond hand grenade range. Parapets, shell holes, and concealment within a limited area are not protection against it. It can, as a striking example, even be used against an enemy around the corner of a wall, by firing against the ground or a wall beyond or in a house or bunker by firing straight into a window. The XM79 launcher is in pilot line production at Springfield Armory and the ammunition at Crosely Avco and Picatinny Arsenal. Distribution to troops will begin soon.
