It's important to note that banning all semi-automatic weapons is a far more expansive stance than most candidates are willing to take (which is remarkable in a year when they've run further Left on some equally important issues).
A semi-automatic gun is a gun that
- Discharges one bullet per trigger pull
- Ejects the spent cartridge
- Loads a new round
This is known as double action in some types of guns (the hammer cocking is part of the trigger pull).
For contrast, a fully automatic (machine) gun is one where you can hold an automatic gun trigger down and it will continue to fire until released or out of ammunition (this category is illegal to manufacture for public sale).
A single action revolver has a chamber that hold bullets and revolves between firings, but requires manually cocking the hammer between pulls as well. These do not qualify as semi-automatic.
Assault Weapons are a poorly defined subset of Semi-Automatic
Most Democrats support Diane Feinstein's Assault Weapons Ban of 2019, which has as cosponsors
- Corey Booker
- Elizabeth Warren
- Amy Klobuchar
- Kirsten Gillibrand
- Bernie Sanders
- Kamala Harris
Virtually all Democrats support an assault weapons ban. They do so because it's a more nebulous term
Some gun experts insist that the term “assault rifle” only refers to a very specific set of weapons: those that are fed ammunition from a detachable magazine, and can switch between semiautomatic and fully automatic fire, a capability known as “select fire.” By that narrow standard, the number of assault rifles in private hands is very small.
But most laws regulating “assault weapons” use a broader definition that some experts say is overly broad. California, Washington, D.C., New York, and five other states have regulations that typically apply to any magazine-fed, semiautomatic rifle that incorporates other design features, which can include a second grip to stabilize the weapon while firing, a rack for mounting accessories, or a muzzle that suppresses the explosive flash of each discharged round. Many of these accessories are mostly for aesthetics, to evoke a combat or “tactical” vibe.
Remember that it's reasonable to assume (no hard statistics exist) that 1 in 3 US guns are semi-automatic. That's a lot of people to tell that you're coming for their property.
The only candidate I can find who has been willing to go out on the "ban all semi-automatics" limb is Maryanne Williamson (emphasis mine)
Eliminating the sale of assault rifles and semi-automatic weapons