He began producing firearms independently by 1831 and shortly thereafter invented a "sliding breech" repeating rifle, also called a Harmonica gun, between 1834 and 1842 while living in Quincy, Illinois.

In 1834, Jonathan and his brother James Green Browning bought farms thirty miles northeast of Quincy in La Prairie, Illinois.

[citation needed] In October 1838, Governor Lilburn Boggs issued the Extermination Order that caused the followers of Joseph Smith to flee Missouri.

[1][2] Browning moved to Nauvoo, Illinois, and joined the community in 1842, buying the Bird home and adding a connecting gunshop.

When the Mormon Battalion was formed during the War with Mexico, Browning wanted to join them, but was told by Young that his skills would not be needed by the soldiers as much as by the main body of pioneers in Kanesville.

He left Mosquito Creek, Iowa, July 8, 1852, and migrated across the Rocky Mountains as the captain of ten wagons in the Henry W. Miller Company.