Just 10 years ago when law enforcement agencies went out to purchase long guns, they rarely looked at anything other than shotguns. But the 1997 North Hollywood bank robbery and the 9/11 attacks have convinced many chiefs and sheriffs that their officers need more firepower. So today the AR and other military-style rifles dominate the market.

At this year's Shooting Hunting and Outdoor Trade Show (SHOT Show) rifles will once again take up much of the space allocated to law enforcement long guns. The following is a look at some of the models that will be on display.

Bushmaster Adaptive Combat Rifle

Bushmaster's ACR is one of the most advanced combat rifles available. Developed in partnership between Bushmaster, Magpul, and Remington, the ACR was designed specifically for military and law enforcement operations. The "Adaptive" in the rifle's name comes from the many configurations available. You can buy an ACR with a 10.5-inch barrel, a 14.5-inch barrel, or an 18-inch barrel. It can be carried and fired with the stock folded. Operators can also adjust the cheek weld and the length of pull. ACR owners can quickly and easily change the rifle's caliber from 5.56mm to 6.8mm Rem. SPC. The ACR features ambidextrous controls; an optional flash hider; hand guard with integral rail, folding, six-position adjustable stock; two-point push-button sling, and optional flash hider.

Colt Defense Law Enforcement Carbines

Colt's flagship police rifles have been around for many years, and they are still considered some of the best on the market. Nick Jacobellis wrote in the July 2010 Arsenal: "The Colt LE6920 is still one heck of a patrol or tactical rifle. Features of the LE6920 include: a four-position collapsible stock, a 5.56mm chamber, a chrome-lined chamber and bore, a barrel with a 1-in-7-inch twist that accommodates ammunition up to 80 grains, an adjustable front sight, a removable carry handle that includes a flip-up front iron sight, and an accessory rail." The LE6920 is available with a 14.5-inch barrel or as the LE6921 with a 16.1-inch barrel. The LE6940 is distinguishable from the LE6920 because it has a one-piece receiver with a monolithic rail and a free-floating barrel.

Daniel Defense Larry Vickers Signature Carbine

Georgia-based Daniel Defense is one of many AR manufacturers known better for its accessories than its firearms. But its latest model may change that. The Larry Vickers Signature Carbine is a luxury AR totally tricked out and ready for duty. Its guts are mostly Daniel Defense, including the upper and the barrel. Other features include a SureFire flash suppressor, a SureFire X300 flashlight, an Aimpoint Micro T-1 aiming system, a Magpul pistol grip, a Magpul trigger guard, a VLTOR iMod buttstock, and a Blue Force Gear Vickers Combat Applications Sling.[PAGEBREAK]

DoubleStar Star 15 Patrol Rifle

The Star 15 Patrol Rifle is built on an A-1 configuration with a one-in-nine twist barrel. Capable of MOA accuracy, the Star 15 Patrol Rifle has a phantom flash hider, a YHM four-rail hand guard, a GG&G flip-up MAD rear sight, a Hogue rubber pistol grip, and a DSC six-position M4 buttstock. Available upgrades include a chrome-lined barrel, a two-stage trigger, an H buffer, and a bipod. The Star 15 is available in a variety of configurations, including a CAR-15 carbine and a match rifle with a 20-inch barrel.

DPMS Panther Arms Agency Rifle

The Agency Rifle is a Panther carbine set up for patrol carry. It's totally fitted out with such details as Mangonel flip-up iron sights, an EoTech 512 HoloSight, SureFire M73 handguard with SureFire M951XM weapons light, ambidextrous safety selector, Ergo Ambi-Grip, two-stage trigger, and a DPMS Pardus Carbine Stock. The basic Panther platform offers a 16-inch chrome-moly barrel, 1-in-9-inch twist; steel bolt carrier; A2 front sight assembly, and A2 flash hider.

FNH USA SCAR Rifles

The acronym SCAR stands for "Special Forces Combat Assault Rifle), which gives you an idea of the roots of this firearm. FN's SCAR is a next-generation military rifle available in 5.56mm and 7.62mm NATO. The SCAR is a short stroke gas piston rifle that is magazine fed, air cooled, and is available in select fire and semi-auto versions. It's also lightweight but has very little recoil thanks to its excellent ergonomics. The SCAR was built for flexibility. Each model can be fitted with three different barrels to achieve different mission goals. The 10-inch barrel and folding stock make the SCAR into a close quarters subgun; the 14-inch and 18-inch barrels are more suited to longer range applications. The side-folding polymer stock is fully adjustable for comb height and length of pull.

Kel-Tec KSG Shotgun

At SHOT Show 2011, Kel-Tec will introduce a compact shotgun, the KSG, that's likely to find a role in future law enforcement operations. The KSG is bull-pup, dual-feed, pump-action 12-gauge shot that holds 14 rounds plus one in the chamber. Barrel length is 18.5 inches and overall length is 26 inches. Kel-Tec says it was able to reduce the size of the shotgun platform because the KSG ejects downward.[PAGEBREAK]

Rock River Arms Law Enforcement ARs

Rock River Arms PDS (Piston Driven System) Carbine is available in two different configurations: 16-inch barrel and 8-inch barrel. First introduced in semi-auto, the PDS Carbine is supposed to be available in a select fire version this year. Available accessories include additional stocks, tri-rail handguards, sights, and optic mounts. Rock River is also expanding its Law Enforcement series ARs to include a 6.8 SPC model, as well as a Short Barrel Rifle (SBR) version.

SIG Sauer SIG556 Patrol Rifle

The SIG 556 Patrol Rifle is available in a tapered profile model or a quad-rail SWAT model. Features on this AR include an adjustable folding stock, a two-position adjustable gas valve, a military grade barrel, and an A2 flash suppressor. The upper receiver is finished in Nitron, the lower is hard coat anodized aluminum. Barrel length is 16 inches with a 1-in-7-inch twist.

Sturm, Ruger & Co. New Rifles

Ruger announced two new law enforcement rifles late last year. In August, the company announced a new version of its SR-556 chambered in 6.8 SPC. The SR-556/6.8 is an AR-style rifle with two-stage piston operation and a four-position gas regulator. Features include a chrome-lined, hammer-forged barrel, Troy industries Folding Battlesights, quad rail and rail covers, Hogue Monogrip, and a six-position stock. Introduced in September, the Ruger Mini Thirty Tactical Rifle is an update of a gun that debuted 20 years ago. The new Mini Thirty is chambered for 7.62 x 39mm ammunition and features a black synthetic stock that cuts its empty weight to 6.75 pounds.