Lock, stock, and barrel
Lock, stock, and barrel is a merism (figure of speech) used predominantly in the United Kingdom and North America, meaning 'all', 'total', 'everything'. The effective portions of a gun (or more specifically a musket) are the lock (used to hold ready the sparking mechanism), the stock (the portion held), and the barrel (the aiming guide and conveyor for the explosive-driven projectile). Collectively they are the whole weapon, and therefore everything.
The term was first recorded in the letters of Sir Walter Scott in 1817, in the line "Like the High-landman's gun, she wants stock, lock, and barrel, to put her into repair." It is, however, thought that this term evolved into a popular saying some years before in England.
In the early days of firearms manufacturing, individual craftsman made individual components one at a time. One craftsman made the "lock" which would have been a "match lock", "wheel lock", "flint lock" etc. The next craftsman made the barrel, and the last craftsman, who was a woodworker made the stock. At some point, a craftsman or a merchant started advertising "Lock Stock and Barrel" meaning that you could get your entire gun at one location and did not have to go from craftsman to craftsman to get it finished.
Lock Stock & Barrel is a book dealing with the restoration and repair of antique firearms, in two volumes.
Officer Lockstock and Officer Barrel are two characters from Urinetown: the Musical. Another musical that used it was the animated musical The Nightmare Before Christmas by Tim Burton featured three infamous children, the 'Trick or Treaters' 'Lock', 'Shock' and 'Barrel'.
Politician Mike Pence, Vice President of the United States under Donald Trump, has heavily favored the phrase since at least 2010 when urging for the repeal of Obamacare, and used the phrase extensively during and after the 2016 presidential campaign.
Lock, stock, and barrel is widely referenced in culture.