After a year that saw more mass shootings than days, many are wondering where the 2020 candidates stand on guns. (CBS)

All 2020 Democratic candidates agree on universal background checks and an assault weapons ban. Here's a quick guide.

Former VP Joe Biden supports banning the sale and manufacturing of assault weapons, and a voluntary buyback program.

Biden has called to register assault weapons and firearms covered by the National Firearms Act.

Bidens also wants to reauthorize the Violence Against Women Act—which he wrote and passed in 1994.

Biden will close the boyfriend loophole, prohibiting those convicted of assault, battery, or stalking from buying guns.

Amy Klobuchar, a co-sponsor of the Assault Weapons Ban of 2019, also supports a voluntary assault weapons buyback program.

Klobuchar would also fund CDC research studying gun violence as a public health issue.

Klobuchar has said she would take executive action to close the boyfriend loophole during her first 100 days in office.

Sen. Elizabeth Warren has called for a federal licensing system requiring all gun owners to license their firearms.

Warren is the only candidate in the 2020 race to call for registering all guns with law enforcement.

Warren will also take executive action to "set the federal minimum age at 21 for all gun sales.”

Part of Warren's plan to pass gun legislation involves eliminating the filibuster.

Pete Buttigieg supports a federal “red-flag” law blocking "individuals deemed mentally unfit" from possessing guns.

Buttigieg supports an assault weapons ban and a federal gun licensing program—but is against a federal gun registry.

Buttigieg on the federal minimum age: "If you can join the [army] at 18, you should be able to buy a gun at 18." (NYT)

Buttigieg has been the only 2020 candidate to link extremism and gun control in his policy plans.

Mike Bloomberg supports an assault weapons ban, a voluntary buyback program, and a federal gun licensing program.

Bloomberg has also called to close the "private sale loophole," which allows for unlicensed online gun sales.

Bloomberg wants to "require gun buyers to be at least 21 years old to buy handguns and semi-automatic rifles and shotguns."

Bloomberg has also called to "ban all guns in K-12 schools, colleges, and universities – except for law enforcement."

Sen. Bernie Sanders supports federal gun registration and licensing for assault weapons, and state licensing for handguns.

Sanders is also a co-sponsor of the Assault Weapon Ban of 2019, and supports a federal assault weapons ban.

Sanders also supports setting the federal minimum age for gun purchases at 21, except for hunting guns.

Steyer supports federal gun licensing and a "national assault weapons registry." He also supports an age minimum of 21.

Steyer also included federal grants for law enforcement "implicit bias" training in his gun violence prevention plan.

Steyer: "Tom will declare gun violence a public health epidemic and dedicate time and resources to develop a cure."

Tulsi Gabbard's campaign hasn't listed any specific gun policy proposals.