A "155" artillery round is a 155 mm (diameter) shell, approximately 6 inches. Examples of guns that fire this type of shell are the 155 mm M114 howitzer, developed just before World War II.
howitzer is a class of gun with many different variants you need to be more specific. but the max range of a M777 howitzer is 30.1 km (rap assisted).
Too broad to answer. You have to define 'gun". A 155 mm howitzer weighs about 7 tons. A double barreled Holland & Holland .600 Nitro Express weighs about 21 lbs.
A howitzer, of which there are many different types.
A large cannon fired at a high angle. See the related link to the M198 155mm towed howitzer and the M109A self propelled howitzer.
Total: 155, Died: 138 (4 were servants) - Survived: 13 which is 8%
A howitzer must be borescoped every 180 days to be considered servicable regardless of if it has been fired or not.
155/80
155 kilogram = 24.4 stone
155 mph is 249.448 kph
155 m = 508.53 ft
155 grams