He spent the final twenty years of his life in the Russian Empire, gaining fame as an engineer-inventor, entrepreneur, and specialist in production.

Notwithstanding this, the Board of Ordnance had granted it a lucrative contract to supply armaments to the British armed forces in 1764.

Gascoigne introduced many improvements in the company's techniques of production, and devoted considerable effort to increasing the quality of its work.

The carronade was designed as a short-range naval weapon with a low muzzle velocity, and is said to have been invented by Lieutenant General Robert Melville in 1759.

The new weapon was a considerable success (earning the nickname "The Smasher" by Royal Navy crews) and remained in production from 1778 through to the 1850s.

In an effort to improve Catherine the Great's weapons foundry at Petrozavodsk, the Russians also ordered a large quantity of plant and equipment.

The British government tried to prevent the company from supplying this cutting-edge military technology; nonetheless, Gascoigne delivered the Russians' orders.

He established the first machine presses at the Saint Petersburg Mint, although the project was ultimately completed by Matthew Boulton.