1. End of crank. 2. Projecting arm of crank handle. 3. Crank handle. 4. Breech casing. 5. Fusee spring } Dotted 6. Chain } lines in 7. Fusee } Fig. 1. 8. Spring box } 9. Resistance piece. 10. Buffer spring. 11. Check lever. 12. Lock casing. 13. Firing lever. 14. Trigger bar. 15. Projection on trigger bar. 16. Trigger. 17. Tumbler. 18. Lockspring. 19. Firing pin. 20. Crank. 21. Crank pin. 22. Connecting rod. 22A. Cotter. 23. Side levers. 24. Sear. 25. Extractor. 26. Barrel. 27. Ejector tube. 28. Horns of extractor. 29. Keeper bracket. 30. Side cams. 31. Cover spring. 32. Cover. 33. Gib. 34. Adjusting screw for fusee spring. 35. Extractor spring. 36. Handles. 37. Double button. 38. Trigger bar spring. 39. Gib spring. 41. Extractor levers. 42. Belt. 43. Upper extractor stop. 44. Groove for side plate spring. 45. Cartridge grooves. 46. Ejector tube spring. 47. Side plates. 48. Guides in which flanges of lock move. 49. Guide ribs for extractor. 50. Cover lock. 51. Gunmetal block. 52. Hole for firing pin. 53. Safety catch. 54. Screwed head. 55. Connecting rod spring. 56. Crank bearings. 57. Slots, breech casing. 58. Crank stops. 59. Ammunition belt box, No. 2. 60. Feed block. 61. Top lever feed block. 62. Cork plug. 63. Feed block slide. 64. Top pawl. 65. Bottom pawl. 66. Band roller. 67. Barrel casing. 68. Screwed plug for filling. 69. Asbestos packing. 70. Packing gland. 71. Cannelure for asbestos packing. 72. Gunmetal valve. 73. Steam tube. 74. } Holes in steam tube. 75. } 76. Slide valve. 77. Steam escape hole. 78. Milled heads of oil brushes. 79. Oil brush. 80. Sight, tangent. 81. Sight, fore. 82. Shutter. 83. Shutter spring. 84. Shutter catch. 85. Notch for shutter catch. 86. Screwed plug for emptying. 87. Slides, right and left. 88. Gib spring cover. 89. Check lever collar. 90. Cover lock spring. 91. Safety catch spring. 92. Tangent sight spring. 93. Bottom lever feed block. 94. Trunnions of barrel. 95. Extractor stop. 96. Firing lever spring. 97. Shutter pivot screw.
Plate I.
GUN MAXIM, ·303 INCH.
SIDE ELEVATION.
Plate II.
GUN MAXIM ·303 INCH.
PLAN WITH COVER REMOVED.
MOUNTING, TRIPOD, ·303-in. MAXIM GUN, MARK IV.
The mounting consists of a crosshead (a), elevating gear (b), and socket (c), mounted on three legs.
It is constructed to give 13 degrees elevation and 25 degrees depression at heights varying from 14½-in. to 30-in. from the axis of the gun to the ground. By arranging the position of the rear and front legs respectively, elevation may be given up to about 43 degrees and depression to 55 degrees. An all-round traverse can be obtained.
The crosshead (a), to which the gun is pivoted, is formed with a pivot to fit into the socket (c) and an arm (d) which carries the elevating gear (b).
The elevating gear, which is actuated by a hand wheel (v), consists of an inner and outer screw (right and left-handed) and a nut working within a tumbler (g). The tumbler is split and provided with a jamming bolt (h), by which the wear may be taken up. The inner part of the screw is attached to the crosshead by a chain. Chains also, for future manufacture and replacement, will secure the joint pins to the mounting.