The 10th Group was the leading force behind the development of the M25 sniper rifle in the late 1980s, at Fort Devens. The rifle is an improvement on the previous M21 sniper rifle, itself a modification of the M14 semi-automatic rifle. During this era the 10th Group acted as the annual training (AT) host for its sister unit in the Army Reserve, the 11th Group. ATs would typically take place during the summer months. As part of its AT support, the 10th Group ran a two-week Basic Airborne course for new 11th Group personnel who were not yet Airborne qualified. The 10th also ran a two-week jumpmaster course for 11th Group personnel. Typically the 10th would run an Airborne course one year and a jumpmaster course during the next. For example, the 10th ran a Basic Airborne course for 11th Group personnel in July 1978 and a jumpmaster course in July 1979. In addition to 11th Group personnel, the 10th sent its own support personnel through its in-house Airborne course, and members of the ARNG's 20th Group were known to attend as well.