The law enforcement carbine is one of the most versatile tools an officer possesses. With its original purpose of bridging the gap between a handgun and the long rifle, the carbine not only bridged the physical gap, but resolved some of the training and deployment inadequacies as well.
Agencies that would have deployed an officer with a handgun to active shooter incidents in the past now issue the carbine (and often body bunkers) across the board. These agencies recognize that it is essential to have a carbine in every patrol car, and overlapping training/deployment plans have become more realistic as a result.
There is evidence that suggests some law enforcement rifle and bullet combinations, specifically light 223 bullets, are safer to use in urban environments than most handguns. Several agencies have reported independent studies of 223 bullets failing to penetrate interior and exterior wall combinations where handgun bullets just keep going. The 223 isn't the only cartridge out there, but it is the one most common to the industry.
Depending on the round, it may have reduced effectiveness or may not even penetrate a pair of exterior walls. The downside to this is the fact that the best after-barrier performers are the highest penetrating in urban environments. That is, the best performers may over-perform when we don't want them to.
The 223 bullet tends to yaw, or deviate from its point of stabilization, quickly in soft tissue. This is desirable, as bullet flipping in tissue tends to expand the wound cavity.
When departments are selecting carbine cartridges, they should consider where they will be employed. Selecting an easily fragmented, light bullet for city use and a high penetration combination for rural use is a good start. Agencies should always perform their own tests with their own firearms when selecting ammo.
The carbine-equipped officer should operate like a tank. Imagine the body divided at the hip, separating the mobility mechanism from the turret mechanism. The mobility mechanism is the way a tank gets to the battle, maneuvers to a position of advantage and maximizes use of the main gun. Although a tank driver makes individual decisions about the terrain, such as not to depress the main gun on steep terrain, he does not make tactical decisions. The command and control section does.
Perceiving the body as divided into mobility and fire control is essential. First, users must recognize that as long as the shooting platform conforms to the carbine, the shot can be successful. Officers can poke their upper bodies around openings, cover down behind vehicle wheels, move stealthily and still make the shot. The mobility section of the body should seek shoulder-width stances when shooting in static situations. A deep stance behind cover is best.
In motion, the knees should be bent and the balance slightly forward. This will lower the center of gravity and put the balls of the feet in charge. The moving stance should be narrower than shoulder width and the shooter should take advantage of the natural shock absorption of bent knees.
Side to side
Moving while shooting is not as hard as it sounds, although police firearms trainers tend to teach forward and rearward movement, as most training movement is toward and away from a static target.
Movement training can be done with traffic cones and officer-coach pairings. Create a maze of traffic cones that the officer must negotiate. The pattern can be as simple as a "Z", where the parallel lines of the letter are parallel to the direction in which the targets face.
Training should be divided into three events: Movement observing muzzle direction, movement observing muzzle bounce and live fire. Coaches should be officers familiar with range operations and understand the objective. The safety briefing must be specific about muzzle discipline and strictly enforced, even during the non-live fire portion.