Original Item: Only One Available. This is a training rifle and it is impossible to convert it into a live round firing weapon. The M16 is completely solid with no moving parts. These trainers, affectionately referred to as “rubber ducks” in the United States Armed Services, were designed to withstand harsh conditions and to take a beating. After personally using one just like this in the Marine Corps, I (Paddy) can vouch for it feeling just like the real thing.

The government didn’t want to risk damaging or losing actual service weapons, so they produced exact copies from actual decommissioned M16A1 parts. They would use real barrels, sling swivels and receivers. They would then cast these components in a resin/rubber coating, hence the name rubber duck. These rifles could now be swam with, dropped from helicopters, thrown off roofs etc and still be fine to train with. So don’t be surprised when you do come across one of these and it's a little beat up, just know that it helped in the training of young service men and women.
 
This rubber duck does show signs of being heavily used, but there is no extensive damage done to it. The receiver has all the same markings as a real Colt M16, featuring the Colt logo, rifle designation, serial numbers and the rates of fire around the selector switch.

This is a beautiful example of a world famous type of rifle, the M16A1.
 
This would be great for any static display or for Vietnam War reenactors!
 
More on the Rubber Ducks
In the United States military, a rubber duck, or "rubber ducky", or "Blue Gun", or "Red Gun" is a non-functional training weapon that is fully or partially made of rubber or plastic. They are usually M16 rifles, and are commonly used in basic training.Trainees are issued rubber ducks to add realism to training without the dangers and maintenance inherent to real firearms. Some JROTC units also use rubber ducks for PT.

For example, rubber ducks are sometimes issued to troops before they have been properly trained to use actual rifles in order to become familiar with basic care, and responsible handling. Other times rubber ducks are issued as a time saver, where proper long-term care of a real firearm would distract from the main training focus, such as tactical combat casualty care training, or land navigation. Rubber ducks are also used where there is a disconnect between safety in the field versus in garrison. During bayonet drills, discharging a weapon against an opponent is to be avoided, whereas in the field discharging the weapon during a bayonet fight is often the goal. And in various ceremonial practices using a rifle capable of firing would serve no purpose.
 
Some rubber ducks are made by filling and coating an actual decommissioned M16 rifle with rubber or plastic. Some are also made using decommissioned rifle parts, with rubber or plastic used for the other parts. Still others are made entirely of rubber or plastic that has been molded to resemble both the exact shape and weight of a rifle.

Rubber duck use is being phased out in some areas of the Armed Forces, namely in Air Force Basic Training. They were replaced with M16 replica Drill purpose rifles: metal models that resemble M16 rifles, including most internal parts, but that lack the ability to fire. The replicas allow soldiers to learn disassembly and reassembly of their rifles much earlier in their training.
 
The M16
The M16 rifle (officially designated Rifle, Caliber 5.56 mm, M16) is a family of military rifles adapted from the ArmaLite AR-15 rifle for the United States military. The original M16 rifle was a 5.56×45mm automatic rifle with a 20-round magazine.
 
In 1964, the M16 entered US military service and the following year was deployed for jungle warfare operations during the Vietnam War. In 1969, the M16A1 replaced the M14 rifle to become the US military's standard service rifle. The M16A1's improvements include a bolt-assist, chrome-plated bore and a 30-round magazine.
 
In 1983, the US Marine Corps adopted the M16A2 rifle and the US Army adopted it in 1986. The M16A2 fires the improved 5.56×45mm (M855/SS109) cartridge and has a newer adjustable rear sight, case deflector, heavy barrel, improved handguard, pistol grip and buttstock, as well as a semi-auto and three-round burst fire selector. Adopted in July 1997, the M16A4 is the fourth generation of the M16 series. It is equipped with a removable carrying handle and Picatinny rail for mounting optics and other ancillary devices.
The M16 has also been widely adopted by other armed forces around the world. Total worldwide production of M16s is approximately 8 million, making it the most-produced firearm of its 5.56 mm caliber. The US military has largely replaced the M16 in frontline combat units with a shorter and lighter version, the M4 carbine.