. The railroad and engineering journal . t-^ -^^ -s. v^x ^^^---^^Sijiii; Fig. 8. the barrel of this 5.3-cm. gun is 73.03 in. The rifling con-sists of 24 grooves of the section shown in fig. 7. Thetwist is right-handed, increasing from i in 165 to i in 30calibers. The entire gun is 80.7 in. long. The diameterof the powder chamber is 2.52 in., that of the bore being2.087 • The gun weighs 595.2 lbs., or with breech-block639.3 lbs. The charge is 1.565 lbs. The shell weighs 4. F I C 10