The XM29 was intended to be an individual combat weapon that combined a rifle and airburst grenade launcher. The XM29 weighed 18 lb (8.2 kg), far more than an individual rifle or grenade launche Its 20 mm airbursting grenades weighed half as much as 540 g (19 oz) 40mm grenades. Even though the grenades were lighter, as a grenade round it was less effective at suppressing the enemy or putting them out of action.