Which grenade launcher attaches to the M16A2E3 rifle?

The 40mm grenade launcher is specifically designed to be compatible with the M16A2E3 rifle. This launcher can fire a variety of 40mm grenades, which are commonly used in modern combat for a range of effects including anti-personnel measures and illumination. The 40mm system enhances the versatility of the M16A2E3, allowing the operator to engage targets at different ranges and with different types of munitions.

Other grenade launchers listed, such as the 20mm, 60mm, and 25mm, are not compatible with the M16A2E3. Each of these systems is designed for different platforms and purposes, which do not align with the specification or mounting capabilities of the M16A2E3. This focus on the correct caliber and compatibility reinforces the logistical and operational utility of the 40mm grenade launcher when integrated with infantry rifles like the M16A2E3.