20mm Burglary Tool
In 1965, Canadian criminal Joel Singer, a 22-year old member of the Montreal-based West End Gang syndicate, stole two WWII-era Lahti L39s 20mm anti-tank guns and 200 rounds of ammunition from a Plattsburg, New York gun dealer.
Singer and four other gang members later used one of these guns in a dramatic late-night burglary when they broke into the vault of the Brinks facility in Syracuse, New York. The Boombeast–equipped with a drum-sized improvised suppressor made from an oil drum filled with steel wool and rubber shavings, then dampened with a wet mattress– cracked open the bank vault after a hail of 33-rounds of AP, allowing the gang to flee with nearly a half mil in cash.
Singer was the 221th person to be added to the FBI’s 10 Most Wanted List on November 19, 1965. He spent two weeks at large before authorities captured him and sent him up the river. Singer later suffered PTSD during the Attica prison riots in 1971 and was released just after on account of this. This 20mm bandit took his own life in 1973 at age 29. In the end, just $166 of the nearly $425,000 taken was recovered.
The use of a 20mm cannon in a robbery was never tried again after this incident. The Brinks job incidentally was the central plot device in a later 1970s Clint Eastwood film “Thunderbolt and Lightfoot” but an unsuppressed US Navy surplus Oerlikon cannon (in puny 20x128mm caliber) was substituted for the Finnish hardware.
Of course, these things have a heck of a kick.