1. up to 100 miles (160 km) per hour
   up to 200 miles (322 km) per hour
2. up to 400 miles (643 km) per hour

A good spud gun can hurl it at up to 400 miles (643 km) an hour.

1. rubber pellets
   potatoes and tennis balls
2. bullets

It can fire potatoes (spuds) and tennis balls, as well as other common objects.

1. fits the barrel size
   doesn't disintegrate
2. conforms to government specifications

STC's owner, by the name of Joel Suprise, says that anything is a worthy projectile as long as it fits the barrel size.

1. "aluminum"
   "pneumatic"
2. "vaporous"

It's called "pneumatic."

1. stainless steel
   quartz
2. PVC

They're usually made out of PVC piping, although some are made of acrylonitrile butadiene styrene (ABS) or aluminum.

1. piston and trigger
   barrel and chamber
2. pedal and knife

Spud guns usually have three main components, two of which are a barrel and a chamber. The third is a firing mechanism.

1. It carves the projectile into a conical shape.
   It shaves off excess potato while you load.
2. It sharpens the potato like a pencil.

The sharpened part, like a barrel knife, shaves off any excess potato while you load it.

1. An explosion creates lots of hot gas under pressure, forcing the projectile out of the barrel.
   It makes a popping sound and the projectile explodes through the barrel.
2. The potato starts to sizzle and then explode, generating enough energy to hurl forward at great speed.

Upon ignition, there is an explosion which creates hot gas under pressure. This forces the projectile out through the barrel.

1. compressed air
   flammable liquid
2. steam

The pneumatic spud gun uses compressed air to generate high pressure.

1. You load the potato through the top opening of the gun.
   You load the potato down the barrel by means of a rod.
2. You open the gun near the chamber and load the potato inside, breech-like.

Breech loading means loading the potato inside through an opening near the chamber (unlike the usual method of forcing the potato down the barrel using a rod).

1. Some gunpowder inside the barrel is ignited using jet fuel.
   Using two metal points, it ignites like a spark plug in a car.
2. Two matches inside rub together and create a spark.

The spud gun has two metal points inside the chamber, which function like a spark plug in a car to cause ignition.

1. so as to keep the spud gun environmentally friendly
   because it doesn't release toxic fumes into the air
2. in order to inject a precise amount of fuel into the chamber using a standard propane tank

They use propane from a standard tank in order to inject a precise amount of fuel into the chamber.

1. They are faulty.
   Because they have a dual ignition system.
2. So they can hurl two projectiles simultaneously.

Some spud guns are designed with dual ignition, essentially creating more "bang" for the same price.

1. a pneumatic spud gun
   a combustive spud gun
2. both have the same size

A pneumatic spud gun usually has a larger chamber than a combustive one.

1. a plug
   a cap
2. a valve

A special valve keeps the air inside, until someone opens it. Then air rushes in with a bang and the potato is forced out.

1. a longer barrel
   a rifled barrel
2. a rifle-like trigger

A rifled barrel seems to work. It gives a spin to the projectile, stabilizing it and hurling it further and with greater accuracy.

1. a massive insecticide sprayer
   a tornado simulator
2. a powerful vacuum machine

A specially-designed tornado simulator was made for the Department of Agriculture. This was done in order to lead to better building techniques.

1. chuck steak
   pumpkin
2. beets

Pumpkin is the projectile-du-jour at the Punkin Chunkin championship.

1. gasoline and oxygen
   propane and carbon dioxide
2. hairspray and aerosol deodorant

Gasoline and oxygen are pretty dangerous in a spud gun. They're too flammable.

1. as firearms under all circumstances
   not as firearms when used recreationally
2. not as firearms, regardless of the circumstances

It classifies spud guns not as firearms, assuming they're used recreationally. This notwithstanding, in most U.S. cities, it is illegal to fire a spud gun.