The AR-15 semi-automatic rifle and similar-style weapons have become both widely popular among gun owners and notorious due to their use in a number of mass shootings over the years.
The rifle "flew off the shelves" when President George W. Bush allowed the ban on assault weapons enacted under President Bill Clinton to expire, The Washington Post reported.
It's lightweight, easy to use and can rapidly fire bullets.
As the NRA says of the weapon's popularity, "it is customizable, adaptable, reliable and accurate that can be used in sport shooting, hunting and self-defense situations."
In California, the gun is legal as long as it's properly registered and certain modifications have not been made.
And while there's no argument as to the rifle's proliferation, Bakersfield police say the number of what's classified as "assault-style" rifles marks a very small percentage of the illegal weapons the department seizes.
It's difficult to pin down an exact number of seized assault-style rifles because they're not booked any differently than regular rifles.
But police spokesman Sgt. Brian Holcombe said a search of BPD records shows the department has made six arrests since 2013 on the charge of manufacturing, distributing or transporting any assault weapon or .50-caliber rifle.
In a related category, officers have made 64 arrests on suspicion of illegal possession of an assault weapon, he said. That category includes anyone who doesn't have the weapon properly registered or has made illegal modifications to it.
"You can legally own long rifles similar to AR-15s, which is what people commonly refer to them as," Holcombe said. "The AR-15 is just a very specific design."
And gun seizures by the BPD's Special Enforcement Unit — the gang unit — also show illegal assault weapons make up a minor portion of the total number of firearms seized.
For instance, so far this year the gang unit has seized a total of 115 weapons. Of those, only 11 have calibers listed that are consistent with legally-owned long rifles and illegal modified rifles.
And in 2017, the unit seized 278 firearms, with 17 having calibers consistent with the assault weapons.
"The point is that this is a relatively small percentage of what we seize out there when it comes to gang investigations and violent factions in Bakersfield," Holcombe said.
"It's a dangerous weapon to come across in the streets, but is relatively low as far as seizures go, so the probability of running into that is a lot smaller than handguns."
Gangsters seek assault weapons because they're a status symbol, Holcombe said. Large rifles such as the AR-15 are powerful, he said, but not practical for someone engaged in illegal activity and trying to remain inconspicuous.
One possible reason the weapons aren't often found on criminals is because they're difficult to conceal, whether on a person or in a vehicle or residence, the sergeant said. Their size proves a liability in terms of keeping them hidden.
Holcombe said any firearm in the hands of someone who wishes to hurt others poses a threat, but those armed with high-powered rifles are a special concern for officers.
"It's an officer-safety issue for people who are willing to do harm with these type of weapons because they do penetrate conventional body armor worn by rank-and-file officers," he said.
The BPD has a rifle program and many of its officers are trained in the use of an AR-15 or similar style weapons. The advantage in arming officers with them is they're very accurate, have a long range and are relatively easy to learn how to use, Holcombe said. Plus they can be accessorized with lights and visual optics such as magnified scopes.
Almost every time the gang unit serves a search warrant at least one of the officers entering the residence will be armed with a high-caliber rifle.
"We know there are situations where these weapons would level the playing field for us," Holcombe said.
It appears the most recent killing in the county involving an assault-style weapon occurred in California City, where police say Desmond Perry shot dead two people with a Smith & Wesson M&P15 rifle — similar to an AR-15.
One of those killed, a 12-year-old girl, was struck in the back when a round passed through a home's front wall, according to court documents.
But it appears crimes countywide involving those types of rifles are relatively low. Kern County Sheriff's Office statistics show a small number of illegal assault weapon seizures when considering the number of weapons deputies take off the streets each year.
To date in 2018, there has been one arrest on suspicion of manufacturing, distributing or transporting any assault weapon or .50-caliber rifle, and four arrests on the charge of illegal possession of an assault weapon.
Last year, the Sheriff's Office made two arrests on the manufacturing charge, and four on the possession charge.
Sheriff's Sgt. Stephen Wells said the laws on what constitutes a legal rifle make it difficult to establish consistency in their statistics. For example, rifles with a "bullet button" — a device used to release a magazine, getting around the state's ban on detachable magazines — are now considered assault weapons and must be registered.
"It’s like every year there’s new gun laws," said Wells, who's seen changes in laws regarding firearms four or five times since he joined the Sheriff's Office.