It has to be remembered that the barrels of these guns would wear out extremely fast. For that reason a part of the guns wouldn't be worth to maintain and would be scrapped. Others were maintained and were used extensively in the second world war. Example for this are the French 155mm guns and the German 15cm guns. Some of these guns would be used in front line duties and others would be assigned to secondary roles such as coastal protection. Examples of heavier guns that remained in service are the 42 cm Gamma Mörser and the 28 cm Haubitze L/12