Complex sentence: He learned gunsmithing from his older brother, J. D. White in 1837 and would later claim that the idea for a "rear-loading" Pepper-box revolver came to him while working in his brother's shop in 1839.
Split into simpler sentences: He learned gunsmithing from his older brother, J. D. White in 1837. He would later claim that the idea for a "rear-loading" Pepper-box revolver came to him while working in his brother's shop in 1839.