Springfield Armory Inc. produces three variations of short M14 type rifles.
1. The 'Bush' rifle which is a conventional M1A with an 18" barrel.
2. the 'Scout Squad' rifle which is the same as the Bush rifle and includes a barrel mounted platform for forward mounting various optical sights.
3. the 'SOCOM' rifle which is a new design featuring a 16.25" barrel, a new design muzzle brake, the barrel mounted optic platform and choices in types of iron sights, Tritium, Match variations etc.
Harrington Richardson was an original Manufacturer of USGI M14 rifles that did experiment with short barrel variations of the rifle after user modified weapons began returning from Viet Nam so altered.
Springfield Armory did not conduct the experimentation with short barrel weapons, they stuck with standard rifles and Match altered varations along with development of sniper grade standard firearms.
Nothing ever came of the short barrel experiments in the time Military use of the M14 was most prevelant, though today short barrel variations of the weapon are being fielded by various Special Operation units deployed in various parts of the world.HTH