https://peertube.dngr.us/videos/watch/bed95f99-b5be-421c-ac9e-947763818584 Want to support this channel and help us preserve old films? Visit https://www.patreon.com/PeriscopeFilm This is a restricted, 1943, black and white Official Training Film presented by the United States War Department, training film TF- 9.2041. It was one of a series made by the Army Service Forces, Signal Corps, to educate ground crew about the 37mm automatic cannon then in use aboard the Bell P-39 Airacobra and the derivative P-63 Kingcobra. The 37 mm Automatic Gun, M4, known as the T9 during development, was a 37 mm (1.46 in) recoil-operated autocannon designed by Browning Arms Company. The weapon, which was built by Colt, entered service in 1942. The purpose of the film is to show the many ways the 37mm - M4 can malfunction and how cleaning and care for the M4 can prevent these problems. The movie opens with a crew chief standing on the wing of an Airacobra ready to help the pilot into a cockpit. Two planes take off 1:00. Pilot moves to engage five Japanese planes 1:22. Plane’s guns malfunction and he is hit by Japanese gunfire - his plane crash lands 1:47. A fellow pilot writes in a journal about the loss of his friend 2:03. Now the backstory -- an Army Air Force mechanic drops a critical piece of the 37mm M4. It hits the ground, and he cleans it off improperly 2:50. Now, the proper way to do it. The 37mm - M4 is shown firing 3:10. The men clean the 37mm - M4 3:33. The M4 is completely disassembled and cleaned by a mechanic 4:00. An animation shows how the bullet is loaded into the chamber 4:22. An airman demonstrates different places to clean the parts of the M4 4:38. A mechanic cleans the different parts of the 37mm - M4 5:14. An airman oils The M4 6:07. The mechanic tightens the end caps of the M4 6:50. An airman fixes a leaking end cap 7:05. The airman is careful not to scratch the recuperator piston rod 7:31. White lead is used on the threads when replacing the end caps 7:51. Only oil AXS – 777 is to be used when cleaning The M4 8:27. The M4 is wiped clean of condensed water vapor and cleaned after coming in from the cold 9:24. Guns are stacked next to one another by the airmen 9:43. Two men clean the front of the M4 on the airplane 10:00. Failure to Feed. Dummy rounds are fed into the M4 feeder 10:13. The airman tests the M4 feeder and it has jammed 10:29. The loading handle rod nut is malfunctioning 11:08. The airman displays why the handle rod nut must function just so 11:40. The guns feed lever is displayed 11:56. The feed box is removed from the M4 12:15. Improperly installed magazines can also cause a failure to feed 12:43. An airman cleans the guide rails of the M4 12:55. Lock Frame Not Held to Rear. The lock frame mechanism is displayed 13:15. A mechanic looks inside the lock frame mechanism and dismantles it 13:48. The carrier cam log has broken off inside the mechanism 14:10. The carrier catch is shown 14:30. The driving spring assemblies are checked 14:50. The driving spring assembly is full of dirt and grease 15:25. An airman cleans the driving spring assembly in a bucket of water 16:05. The lock frame is binding badly for the airman and he must clean the inside 16:45. Failure to Load. The mechanic first inspects the lock frame 17:35. The round is jammed inside the loading mechanism 18:10. The round is not positioned correctly in the extractor because of a damaged rear lip 18:45. Failure to Fire. An animation shows how the hammer is released and rounds are loaded and fired 19:24. The sear spring is removed 19:43. The trigger bar must operate freely in order for firing to occur 20:15. A Sluggish Gun. The tube and tube extension are returning to battery slowly 21:06. A printed screen says: Sluggish Gun, Binding of Driving Springs, Foreign Matter in Receiver, Too Much Oil 21:15. The adjustment of the recuperator piston is checked 21:28. The front piston of the M4 is tightened carefully 22:07. Failure to Extract. The lock frame is held to the rear as the tube extension separates 22:48. The airman works with the round feeder 23:20. The P-39 in flight 23:40. The End. T. F. 920 41. End card: This Film Will Not Be Shown to the General Public without the Permission of the War Department. The M-4 autocannon had a muzzle velocity of 2,000 ft/s (610 m/s) and a cyclic rate of 150 rounds per minute. It was normally loaded with high-explosive shells, but could also be loaded with the M80 armor-piercing shell, which could penetrate 1 inch (25 mm) of armor plate at 500 yd (460 m). The M-4 was disliked by pilots for its drooping trajectory. This film is part of the Periscope Film LLC archive, one of the largest historic military, transportation, and aviation stock footage collections in the USA. Entirely film backed, this material is available for licensing in 24p HD, 2k and 4k. 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