The system was under development by General Dynamics Armament and Technical Products for the U.S. Army Tank-Automotive and Armaments Command (TACOM).
As a part of the Small Arms Master Plan (SAMP) program, it is intended to either replace or supplement the Mk19 automatic grenade launcher and the M2 heavy machine gun.
 It fires 25 mm point-detonating and air burst style ammunition, including HE, and HEAT at a cyclic rate of 260 rounds per minute and has an effective range up to 2 kilometers.

The primary feature of the XM307 is its attenuated recoil system.
 The weapon controls recoil to a degree that a large tripod and heavy sandbags are not required to effectively employ this weapon.
 Because of its reduced recoil impulse and light weight, other mounting options are  possible, such as small unmanned vehicles and aircraft.
The XM307's airburst rounds make it much easier to bypass walls protecting enemies that could cause collateral damage if fired upon directly.
Operators do not have to shoot through the wall, just through an opening or over the top to kill the people behind the cover, leaving the structure of the building intact.
An additional feature of the XM307 is that it can be converted into the XM312, a 12.7 mm (.50)-caliber version for infantry and light anti-armor support in under two minutes (1 minute, 42 seconds).
The system was under development by General Dynamics Armament and Technical Products for the U.S. Army Tank-Automotive and Armaments Command (TACOM). As a part of the Small Arms Master Plan (SAMP) program, it is intended to either replace or supplement the Mk19 automatic grenade launcher and the M2 heavy machine gun.  It fires 25 mm point-detonating and air burst style ammunition, including HE, and HEAT at a cyclic rate of 260 rounds per minute and has an effective range up to 2 kilometers.
The primary feature of the XM307 is its attenuated recoil system.  The weapon controls recoil to a degree that a large tripod and heavy sandbags are not required to effectively employ this weapon.  Because of its reduced recoil impulse and light weight, other mounting options are  possible, such as small unmanned vehicles and aircraft. The XM307's airburst rounds make it much easier to bypass walls protecting enemies that could cause collateral damage if fired upon directly. Operators do not have to shoot through the wall, just through an opening or over the top to kill the people behind the cover, leaving the structure of the building intact. An additional feature of the XM307 is that it can be converted into the XM312, a 12.7 mm (.50)-caliber version for infantry and light anti-armor support in under two minutes (1 minute, 42 seconds).
XM307 Advanced Crew Served Weapon