California governor on shootings: "What the hell is going on" 2:29
(CNN) --
California has some of the strictest gun laws in the country, according to advocacy groups.
However, the state has been rocked by three mass shootings in 44 hours.
At least two of the suspects carried out the attacks with semi-automatic weapons and at least one of the weapons was illegal in the state.
We spoke with Jennifer Mascia and Stephen Gutowski, contributors to CNN's "Guns in America," to learn more about the firearms used in each of the shootings.
The following questions and answers have been lightly edited for clarity and brevity.
Monterey Park: 11 dead, gunman dead
The weapon used in the shooting was either a MAC-10 semi-automatic assault weapon or an M11 Cobray, according to authorities (both have been said). What does that mean and is that type of weapon legal in California?
JM:
First of all, a word of caution: an original MAC-10 – the Military Armament Corporation Model 10 – is usually a fully automatic machine gun.
That means several bullets are ejected for each trigger pull.
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Machine guns are heavily regulated by the National Firearms Law.
The weapon he used was not a machine gun.
Among the variants of the MAC-10 is the Cobray M11/9, which was first reported to have been taken from the attacker.
Security footage shows the suspect entering a door.
Courtesy of Brenda Tsay
The MAC-10 variants are illegal under California's assault weapons ban for two reasons: they have a threaded barrel, and they are designed to take 30-round magazines.
Any weapon larger than 10 rounds is illegal under California law.
SG:
The gun that was taken from you appears to have had a suppressor/silencer attached to it, meaning it likely had a threaded barrel which would make it illegal to purchase today.
It's also not legal to buy today because California has banned the sale of handguns without certain features, such as a magazine lock, a loaded chamber indicator, or "microstamping" technology (which no gun company currently produces).
However, the suspect in this case is 72 years old and Trace by the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) indicates that he bought the gun himself.
We need more information about when the purchase was made.
But since the company that made it went bankrupt in the 1990s, it's possible he bought it legally before California's "assault weapons" ban went into effect.
These are the victims of the shooting in Monterey Park, California
Was any modification made to the weapon? If so, did it make it more dangerous and/or illegal?
SG:
CNN reports suggest that police believe the shooter was illegally manufacturing suppressors, also known as silencers, at home.
The video in which Brandon Tsay disarms it shows what appears to be a silencer attached to the end of the barrel.
California has a total ban on even the possession of mufflers.
Therefore, it was not legal for him to have it.
Suppressors reduce the sound of gunshots.
However, they don't actually make a shot silent.
Depending on the caliber and the effectiveness of the suppressor, they generally reduce sound to the same decibel level as a jackhammer.
Suppressors work exactly like car mufflers and were invented by the same person (Hiram Percy Maxim).
The shooter in the Monterey Park massacre is dead, but the motives for the shooting that occurred during the Lunar New Year celebrations remain unknown.
How could he shoot so many times?
SG:
Police report that the shooter used a 30-round magazine, the sale of which is prohibited in California.
Given the suspect's age, he too could have purchased the charger before California instituted its ban several decades ago.
California passed a forfeiture law in 2016 that prohibited the possession of magazines larger than 10 cartridges.
However, a federal judge blocked its application on the grounds that it violates the Constitution, and that case (Duncan v. Becerra) is still in court.
Furthermore, survivors reported that it also reloaded during the attack.
Therefore, the size of the magazine did not prevent him from having to reload his weapon at least once.
Also, the pistol you used can fire cartridges at basically the same rate as any other semi-automatic firearm (one shot per trigger pull).
The gun had a long barrel at the end, what is it and what is it for?
JM:
I think it's a silencer that muffles the sound of the shot.
But law enforcement have not confirmed it.
Silencers are regulated by the same federal law that regulates machine guns.
You would have had to register the device with the federal government to legally possess it.
Half Moon Bay: 7 dead, attacker in custody
Authorities have said it was a semi-automatic weapon, legally registered in the attacker's name.
How is this pistol different from the semi-automatic used in the Monterey Park shooting, and why is it legal and the other is not?
JM:
The Monterey Park pistol is not legal in California because it has features banned by the state's assault weapons ban: a threaded barrel, and it's designed for 30-round magazines.
The weapon used in the Half Moon Bay shooting was a registered semi-automatic pistol that did not have any of the characteristics listed in California's assault weapons ban.
Most pistols in circulation are semi-automatic, which means that another round automatically enters the chamber after firing.
No need to manually cock it, like a revolver.
What does the number of victims say about the type of weapon used?
JM:
AR-15s are especially deadly, so they leave fewer survivors, but most mass shootings are carried out with small arms.
The Half Moon Bay shooting was so deadly probably because he took aim at his victims and shot them at close range.
With the Monterey Park shooting, I knew immediately that the shooter had not used an AR-15 because there were so many survivors.
A MAC-10 variant and other "assault pistols" come closer in lethality and functionality to a pistol than an AR-15.
They're old, heavy, and not terribly accurate, so the death toll was more like a small arms attack than an assault rifle attack.
SG:
Unfortunately, when an armed person attacks a group of unsuspecting and unarmed people, it doesn't take any advanced weaponry or tactics to inflict a horrific toll on a community.
Mass murder has been committed with all types of weapons, from semi-automatic rifles and pistols to pump-action shotguns, bolt-action rifles, knives or blunt weapons.
Half Moon Bay, Monterey Park and Oakland: this was the three mass shootings that shook California in three days of terror
Oakland: one dead and one attacker on the loose
So far, the police have not found any weapons, only shell casings.
Can you trace the type of weapon using those casings and/or the victim's wounds?
JM:
The casings can be searched in NIBIN, the ATF's ballistics database, to match them with casings found in other shootings.
But the NIBIN does not provide the serial number of the weapon or the chain of custody.
However, you can connect attackers from different jurisdictions and prevent them from firing again.
SG:
The police can identify the caliber of the weapon used in the attack from shell casings recovered at the scene or from the wounds of the victims.
However, it is much more difficult to determine the specific firearm used in an attack from the casings or the wounds.
Firearms California Massacre
