Law enforcement firearms must be dependable, accurate, and provide the firepower necessary for protection of life. More often than not, law enforcement weapons issued by a department are chosen by the administration. However, many officers choose to purchase their own weapons and their choices provide an image of the law enforcement profession as a whole. Part of the determination as to what is the issued weapon by the administration is the cost per firearm.
Glock is an Austrian manufacture that introduced the Glock 19 in 1988, quickly becoming popular with law enforcement agencies.
Glock 19: This is the smaller version of the Glock 17, usually used by plain-clothed officers and citizens with a permit to carry a concealed weapon. It holds 15 rounds of 9mm cartridges and its barrel is almost four inches smaller than the Glock 17. It weighs just under 30 ounces when loaded. It has minimal recoil (9mm) and allows a full grip despite it being seven inches shorter than Model 17. It has three independent safety mechanisms; although there is not an external safety lever or button. One is built into the trigger, preventing it to be fired only when completely depressed. There isn't much to maintenance and works in extreme temperatures or when dirty. The matte finish is durable, important because it is kept in and taken from a holster that may not have inserts that minimize wear.
Glock 22: This model is heavier than the Model 19, although both use 9mm ammunition; but the Model 22 also is available in .40 caliber. It is a bit harder to conceal, so most Glock 22 models are carried in the law enforcement holster on their utility belt. The .40 caliber ammunition is popular because it is between the 9mm and ,45 caliber; thus accurate group shots can be acquired more easily. In looks, the Model 22 is not too different from Model 19.
Smith & Wesson M&P 9: In 2013, the LA County Sheriff Department began issuing the S&W M&P (Military & Police) Model 9, which ended the issue of the Beretta Model 92, 9mm pistol used by US Armed Forces. According to the department, this was determined because the S&W pistol offers a more individual preference of individual officers and features not available on the Beretta. It is a full-size semi-auto with a barrel just over 4 inches. One thing it features that law enforcement officers like is that it has a loaded chamber indicator to allow visual confirmation that a round is chambered without moving the slide. The pistol has a high capacity magazine like the Beretta and fits the hand well. There are also aftermarket accessories available, which is popular with law enforcement officers. The Picatinny rail under the muzzle provides the ability to add laser sights and ambidextrous controls for left-handed officers. S&W is not new to law enforcement pistol requirements, before the semi-auto became popular, their revolver models were weapons of choice.
Beretta Model 92: This firearm began to be produced by Beretta, an old established Italian firearm manufacturer known for its quality shotguns, in 1975 after five years of testing. The company was focused on the pistol to be used by military and law enforcement personnel. It is made with a light, aluminum alloy frame (like used in aircraft) and easy to disassemble like the Colt Model 1911, formerly the issued firearm of the US military. In 1990, Beretta introduced the Model 92 for law enforcement officers, with a high-capacity magazine and a chrome-lined barrel that prevents corrosion without affecting accuracy. The take-down latch on the side helped in simple disassembly and reassembly. It uses 9mm ammo.
Sig Sauer P226: Another quality firearm manufacturer, the Model P226 was developed from the Model P220 in an effort to compete for a US Army contract to replace the Colt Model 1911. The magazine has a larger capacity than the P220 and the magazine catch is ambidextrous. Sig Sauer did not get the contract because of the cost, but is the favorite of personnel who purchase their own duty firearms by the US Navy SEALS, US Coast Guard, Federal Air Marshals, and the FBI. It is easily handled and fits the hand well, and the longer barrel provides better accuracy.
Heckler & Koch HK45: Another pistol that is the favorite among US Navy SEALS and made by a manufacturer known for its quality firearms is the HK45 for its power and versatility. It has a changeable grip panel, accessory rail and better ambidextrous controls. It has an internal mechanical recoil reduction mechanism that can reduce recoil as much as 30%. It is fitted with threaded barrels for muzzle brake or suppressors. It uses the same round as the Model 1911, .45ACP. It has a combination safety and de-cocking lever that are easily accessible. Users/owners of these firearms say they are rugged and accurate considering its size.
Ruger LC9: This might surprise some to be on this list, but this model Ruger is popular with those who carry concealed or those law enforcement officers who want a concealed backup firearm. The original version was in .380 caliber and that was not popular with law enforcement officers, so Ruger made them chambered for 9mm Parabellum cartridges. However, most police departments do not choose the Ruger because of price; but law enforcement officers report that they often keep the Ruger LC9 as their personal, off-duty weapon of choice. It has a double-action only trigger, manually operated thumb safety that locks the hammer and trigger, and is six inches long and less than one-inch wide. It weighs about 17 ounces. This is poplar for females to carry in purse or places were a larger firearm would be prohibitive.
In the shotgun category, there is the …
Remington 870 Shotgun: This shotgun has long been a favorite of law enforcement officers and administrations, a familiar site in a patrol car resting on a dashboard mount. The Model 870 has double action bars and Remington's reputation for reliability. It is the bestselling shotgun Remington has to offer. It is made at the New York state plant in a special area where the same personnel work in that section during each shift. The shotguns go through a special 23 station check list and each part is visually inspected by hand.
The most popular rifle for law enforcement is also that which is used by US Armed Forces …
Colt M4 Carbine: This light-weight gas-operated rifle was purposely created by Colt for the military and law enforcement personnel. Soldiers fighting in urban areas needed something short enough for close quarters and as reliable as the M16. It has selective fire options, with a full-auto option replacing the three-round option found in the issued M16. The M4 Carbine can be fitted with night vision devices, lasers, telescopic sights, and other accessories like the M203 or M320 grenade launcher. Most law enforcement circumstances do not require a grenade launcher, but it comes handy when needing to fire tear gas rounds into window openings. The firearm, as in all M16 and AR15 models filed strips with no special tools required and the unique direct gas system eradicates the need for a conventional operating rod that make it more dependable and lighter.
I am sure you could find law enforcement officers using other models of those manufacturers mentioned, but these are the most favorite.