Stop! Or My Mom Will Shoot is a 1992 American action comedy film written by Blake Snyder, William Osborne and William Davies, directed by Roger Spottiswoode and starring Sylvester Stallone and Estelle Getty.
A tough cop’s (Sylvester Stallone) seemingly frail mother (Estelle Getty) comes to stay with him and progressively interferes in his life. She buys him an illegal MAC-10 machine pistol and starts poking around in his police cases.
Though she seems frail and weak, she proceeds to help with with both his love life and a case he his working on.
Summary via Wikipedia.