This reminds me of the "Supergun" that Gerald Bull [2] was trying to build with Saddam Hussein [1].
One of my professors, that worked with Bull at the University of Toronto, told me all about his arms dealing/designing escapades. Bull was ultimately assassinated outside his home in Brussels.
Before he was working with Iraq, he worked on Project HARP, which was funded by the USA and Canada.
They did managed to get a projectile to space. They had plans to try and get one to orbit, using a rocket as a second stage, but the project was cancelled before that came to fruition.
[0] https://smbc-comics.com/soonish/