DEWAT C-7 rifle with magazine from DHH, serial number 91AA12038. Everything has been welded shut. The Colt Canada C7 is a Canadian assault rifle, manufactured by Colt Canada (formerly Diemaco prior to 2005), a variant of the Armalite AR-15, and having similar design and function to the Colt M16A3. The development of the C7 assault rifle paralleled that of the M16A2 by Colt. A Canadian Forces liaison officer worked with the United States Marine Corps in the MA6A1 Product Improvement Program and relayed information to Canada's Rifle Replacement Program Office. The C7 is much like earlier M16A1E1s, rather than final product M16A2s. The earliest C7s were manufactured by Colt for Canadian Forces as the Colt Model 715. The C7 series of firearms is driven by the same direct impingement gas system as the M16 series. Like the M16A1 and M16A3, the C7 has both semi-automatic and fully automatic fire modes. The C7 also features the structural strengthening, improved handguards, and longer stock developed for the M16A2. Diemaco changed the trapdoor in the buttstock to make for easier access, and a 13 mm (0.5 in) spacer is available to adjust stock length. The most noticeable external difference between American M16A2s and Diemaco C7s is the retention of the A1 style rear sights. Not so apparent is Diemaco's use of hammer-forged barrels, introduced as the Canadians originally wished to use a heavy barrel profile instead of the M16A2 profile. Also, Diemaco has developed a different mounting system from Colt for the M203 grenade launcher for the C7 rifle family. The C7 has a cyclic rate of fire of around 700–900 rounds per minute (RPM). In 2007 and 2008, Canada donated 2,500 surplus C7 assault rifles to the Afghan National Army. In 2011, the ANA gave back the C7s since the Afghan security forces chose the American M16 instead. Canadian Forces officials said the Canadian rifles would be shipped to Canada for disposal.