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Canadian Forces  Grenade Launcher   —   Diemaco  40mm  M203A1

The standard CF grenade launcher is a Canadianized M203 firing the low-velocity 40mm x 46mm grenade.  Based on the original  US Army M203 devised by AAI/Colt [1],  the Diemaco  M203A1 was modified to meet the CF's requirements. Like the US Colt M203A1, Diemaco's similarily-designated M203A1 has a 9-inch barrel. The big difference between US and  Canadian systems is  Diemaco's mounting system, which places the launcher barrel  lower (to accommodate the distinct barrel profile of CF C7/C8 series weapons). The lower barrel position also results in slightly different trigger guards. However, in their role as suppressing-fire anti-personnel weapons, M203s are all the same.

M203 actions are also similar. The firing cycle is entirely manual with  the rifle magazine acting as a hand grip.  A lever opens the breech, a  grenade is pushed  into the breech (left) and  the tube slides back  to cock  the weapon. The M203 can be fired directly at close-range targets or indirectly using the folding ladder-type sights – which can be attached to either side of the mount (far right). CF infantry sections usually have two M203A1 grenadiers (each of whom carry 12 of  the 40mm grenades).

 Diemaco  M203A1  Grenade Launcher  Specifications
  Name:   Launcher,  Grenade,  40mm,  M203A1
  Round:   NATO 40 x 46mm SR  low-velocity grenades
  Action:   Breech loading / single shot / pump action
  Barrel:   40mm rifled tube, aluminum construction
  Bore:
 
  22.8cm (9") long , rifling:  six lands, twist rate:
  one turn per 121cm of travel, right-hand twist
  Weight:   unloaded  1.85 kg ,  loaded  6.81 kg
  Range:   25m (arming) to 450m max. (350m effective)

An M203A1 is installed by removing the C7 lower hand guard  ( a replacement hand guard comes with each grenade launcher ). An armourer must  install  the M203A1 but the launcher can be readily removed with a quick-release pin. The launcher can be mounted on any C7 without modification ( but a longer sling is required and, on the C7A2, the M203A1 interferes with the Triad rail mount). In combat in Afghanistan the M203A1 launcher has proved to be invaluable, the 40mm fragmentation grenades  –  in combination with disposable M72 rocket projectiles  –  giving excellent suppression coverage when troops advance or  are under fire.

[1] The M203 was developed in the mid-'60s by AAI Corporation working under a US Army contract. Colt began mass production in 1971.

Photo Credits – sideviews: Stephen Priestley, centre right: Dale MacPherson, bottom right, modified RWM Arges, all others: DND/CF