Each piece had its chamber formed of thin metal and embraced by strong iron rings; over these was placed a form of hardened leather, which was again encircled with rings and held compactly together.

These pieces were mounted on light carriages, so that two men could easily manoeuvre them.

It was said that they would fire from eight to ten rounds without requiring repairs.

Gustavus made use of them in all his military operations from 1628 to the time of his death.

They did him excellent service on numerous occasions; being so very light they could be easily transported, and, on the field of battle, their movements could be made to conform to the movements of his troops.
As cannon and small arms were gradually introduced into general use, various inventions and improvements were proposed and introduced from time to time.