Glock locked his ex-wife out of the mansion they shared in Austria and fired their three children from the company before marrying his nurse, Katrin Tschikof, who is 50 years his junior.
The new Mrs Glock began caring for him in 2008 when he suffered a stroke, and is now on the company's advisory board.
His children Brigitte, Gaston jnr and Robert claim that she restricted access to their father and that he no longer speaks to his grandchildren.
The gun company was founded in 1963 with money that the newly-wed Glocks had originally saved to buy an apartment in Vienna.
Instead, they bought land to build a factory, making a gun Glock had designed for the Austrian army. The firm was wildly successful, and the Glocks moved to America in 1985. Soon afterwards, Glock is said to have transferred 50 per cent of the company into a subsidiary firm, a move Helga Glock says she did not discover until the divorce.
Her lawsuit claims Glock went on to spirit away about half a billion dollars from the family firm.
In a statement submitted as part of the case, Peter Manown, a former vice-president of Glock, said Glock "spends money on mistresses, on houses, on sex, on cars. He bribes people. He's just a bad guy."
Helga Glock was also apparently kept in the dark about a sinister episode in which one of her husband's partners tried to have him murdered with a mallet to cover up a US$100 million embezzlement. Charles Ewert, who was nicknamed "Panama Charly" for his use of shell corporations in the South American country, is serving 20 years in prison in Luxembourg for the attempted murder, which left Glock bloodied and injured.
Helga Glock also claims she and her children were tricked into giving away the rights to foundations now used to fund a horse farm where the Olympic show-jumper London is stabled - a gift to the new Mrs Glock from the gun tycoon, and at US$15 million the most expensive horse ever sold.
Glock Inc and Glock did not comment.
