The Ruger Mini-14 rifle employs a cast, heat-treated CNC receiver and a version of the Garand's breechbolt locking system, with a short-stroke fixed-piston gas system and gas cylinder derived from the M1 Carbine. The rifle is available in a variety of finishes from stainless to blued with synthetic or hardwood stocks and has a standard 18.5 inch barrel.

 One reason for the popularity of the Mini-14 is that it does not have the menacing 'military' appearance that is associated with the AK-47 and M16. This resulted in most variants of the Mini-14 being specifically excluded from the now-expired federal and many state bans on so called "semi-automatic assault weapons", even though the Mini-14 was functionally equivalent to, and even fired the same ammunition as, other prohibited firearms.

 The standard Mini-14 lacks such legislatively defined militaristic features as a bayonet lug and flash suppressor, though all of these are available through aftermarket alterations.

The Mini-14 has proved popular with small game hunters, ranchers, law enforcement, security personnel and avid plinkers.

 Common accuracy for a stock Mini-14 (ranch rifle) is 2.5-4 MOA. It is a very rugged and robust design which addresses one of the M14's shortcomings with a 'self-cleaning' gas system.

 The Mini-14 in its various guises has been adopted by various police and paramilitary forces around the world.

 In 1978, the Mini-14 rifle was purchased by the Royal Ulster Constabulary to replace its stock of aging U.S. M1 carbines.

 In 1983, The Bermuda Regiment replaced its British made L1A1 SLR's (7.62 mm) with the wooded stocked Mini-14 20GB, a semi-automatic only variant.

 In 1993, the wooden stock of the Mini-14 was replaced with a Choate black fibreglass stock complete with pistol grip. Retrofitted to older Mini-14s, this stock, with its straight-line buttstock, adversely affects sight line.

 Ruger made significant design alterations to the Mini-14 in 2004 which changed the receiver and front sight configuration. All new Mini-14s come with integral scope bases, and use a ghost ring rear sight and a winged front sight similar to that used on the Ruger Police Carbine.

 There is also a Mini-14 variant, called the Ranch Rifle that has scope bases integrated into the receiver, and an ejector that ejects the brass at a lower angle to avoid hitting a low mounted scope. Both the Ranch Rifle configuration and the stainless steel variants are more expensive than the standard rifle.

 Two militarized versions were also produced:
1. The K Mini/14-20GB which featured a fiberglass handguard, flash suppressor and a bayonet lug.
2. The AC-556, identical to the K Mini/14-20GB, but in addition came with selective fire capability and an optional folding stock.

 While the Mini-14 was never adopted by the U.S. military, both civilian and military Mini-14 variants are popular with some police departments as a medium-range weapon to fill the gap between handguns and shotguns, and sniper rifles.

 Some K Mini/14-20GB's originally sold to US Law enforcement agencies have been released to the civilian market. Often these carbines carry dual serial numbers and are more desired by collectors due to their LE background. Likewise the factory flash suppressor and bayonet lug are more rugged than the typical aftermarket and adds to the appeal.

 Beginning in 1987, Ruger also began manufacture of another variant of the Mini-14, called the Mini-30. The Mini-30 is chambered for the Russian 7.62×39 mm.

 Unfortunately, the Mini-30 had not been designed to use the corrosive-primered surplus 7.62 x 39 mm ammunition then widely available on the civilian market, and the rifle's barrel and gas system were sometimes destroyed through rust and neglect. The Mini-30 is currently available only in a configuration similar to the Mini-14 Ranch Rifle, with integral scope base and low-angle ejection.

 Some earlier Mini-14 rifles were chambered in the .222 Remington cartridge, which was the basis for the development of the military 5.56x45 mm NATO and the civilian equivalent the .223 Remington. Since the .223 Remington is dimensionally equivalent to the 5.56x45 mm, civilian firearms chambered in that caliber are highly restricted in countries that restrict or prohibit firearms that chamber military cartridges (such as Mexico).

 A larger version of the Mini-14, called the XGI, was developed by Ruger in .308 Winchester and .243 Winchester, but while it was advertised in 1985, it never entered production due to continued accuracy and functioning problems.