According to the link from Guns & Ammo Network :

> http://www.gunsandammo.com/blogs/history-books/firearms-nicknames/

There are some word that describe average weapons and handguns:

AKAs such as “Heater”,  Shooting iron”, “Smoke Pole” and “Persuader” are pretty easy to figure out, as are *“Saturday Night Special”*, *“Suicide Special”* and *“Flyapart”*, the latter a trio of terms to describe cheaply-made, inexpensive handguns intended for limited, somewhat specialized usage.

Hope it helps you.