Colt’s 1969 Piston Rifle

In 1969 Colt offered their model 703 as an upgrade to the M16 and M16A1 rifles. There is a well-traveled rumor that this rifle was known as the M16A2 because Colt was confident it would be adopted. While this could very-well be true, it is further confused by the fact Colt re-used the 703 designation for direct gas impingement M16A2 export models.

Colt 703 a

The Prototype 1 had a four position selector that was omitted on later models. Also omitted was the slot in the stock for a sling.

The following stats are taken from a May 1969 Colt data sheet.

Model 703 Prototype 1 M16A1
Overall Length
Barrel Length
Barrel Rifling
six groove, 1/12″ twist
Height (without magazine)
Height (with 30rnd magazine)
Weight (without magazine) 6.9 lbs 6.5 lbs
Weight (with loaded 30rnd magazine) 8.7 lbs 8.3 lbs
Weight of Reciprocating Group 1.33 lbs 1.0 lbs
Muzzle Velocity
3250 ft/sec
Muzzle Energy
1285 ft-lbs
Rate of Fire gas adjustable 600-800 rpm 700-940 rpm
Operation “Piston Impingement” “Piped Gas”
Parts Count 143 164
Total Unique Parts

The firearm can be seen at Knights Firearm Museum. Interesting to note is the Knight’s museum appears to have Prototype 1, as well as a later 703 model; The World’s Assault Rifles claims only two were ever made. The M703 or CAR Model 703 should not be confused with the Colt ACR, a future prototype, which Olin developed the ammunition for.

The 703 piston and bolt carrier were attached via a “hinge”. The piston, piston hinge pin, and piston mounting block of the bolt carrier can be seen in the photo below.

Colt 703

Colt’s Firearm Division, Colt’s Automatic Rifle Model 703 1969-05
Johnston & Nelson, The World’s Assault Rifles, Ironside Intl. 2010 p.1051
Sapp, Rick, Standard Catalog of Colt Firearms, Gun Digest Books 2007 p.225

As always, we like corrections, but we like corrections with references even more.

4 comments to “Colt’s 1969 Piston Rifle”
  1. Pingback: Aftermath Gun Club | Knight’s Museum Stoners

  2. Pingback: The Original Piston AR-15: 1969’s Colt 703 | Five Dollar Army

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