15 cm sFH 18 The 15 cm schwere Feldhaubitze 18 or sFH 18 ( German : " heavy field howitzer , model 18 " ) , nicknamed " Immergrün " ( " Evergreen " ) , was the basic German division - level heavy howitzer during the Second World War , serving alongside the smaller but more numerous 10 . 5 cm leFH 18 . It was based on the earlier , First World War - era design of the 15 cm sFH 13 , and while improved over that weapon , it was generally outdated compared to the weapons it faced . It was , however , the first artillery weapon equipped with rocket - assisted ammunition to increase range . The sFH 18 was also used in the self - propelled artillery piece " schwere Panzerhaubitze " 18 / 1 ( more commonly known as " Hummel " ) . The sFH 18 was one of Germany ' s three main 15 cm calibre weapons , the others being the 15 cm Kanone 18 , a corps - level heavy gun , and the 15 cm sIG 33 , a short - barreled infantry gun . Design and development . The gun originated with a contest between Rheinmetall and Krupp , both of whom entered several designs that were all considered unsatisfactory for one reason or another . In the end the army decided the solution was to combine the best features of both designs , using the Rheinmetall gun on a Krupp carriage . The carriage was a relatively standard split - trail design with box legs . Spades were carried on the sides of the legs that could be mounted onto the ends for added stability . The carriage also saw use on the 10 cm schwere Kanone 18 gun . As the howitzer was designed for horse towing , it used an unsprung axle and hard rubber tires . A two - wheel bogie was introduced to allow it to be towed , but the lack of suspension made it unsuitable for towing at high speed . The inability of heavy artillery like the sFH 18 to keep up with the fast - moving tank forces was one of the reasons that the Luftwaffe invested so heavily in dive bombing , in order to provide a sort of " flying artillery " for reducing strongpoints . The gun was officially introduced into service on 23 May 1935 , and by the outbreak of war the Wehrmacht had about 1 , 353 of these guns in service . Production continued throughout the war , reaching a peak of 2 , 295 guns in 1944 . Several other versions of the basic 15 cm were produced . The 15 cm sFH 36 was a version with a greatly reduced weight that was an attempt to improve mobility , but as it used various light alloys to achieve this savings it was considered too costly to put into production . The 15 cm sFH 40 was another improved version , featuring a slightly longer barrel and a new carriage that was suitable for vehicle towing and allowed the barrel to have wider firing angles and thereby improve range up to 15 , 400 m . However this version was even heavier than the sFH 18 ( at ) and was found to be too difficult to use in the field . Some of these barrels were later fitted to existing sFH 18 carriages , creating the sFH 18 / 40 . A further modification was the FH 18 / 43 , which changed to a split breech that allowed for the use of bagged charges instead of requiring the gunners to first put the charges into shells . Two further attempts to introduce a newer 15 cm piece followed , but neither the 15 cm sFH 43 or 15 cm sFH 44 progressed past the stage of wooden mock - ups . Combat record . The first field combat for the 15 cm sFH 18 was with the Chinese National Revolutionary Army in the Second Sino - Japanese War . The Chinese were desperately short on artillery guns and other heavy weapons , but the few 15 cm sFH 18 units the Chinese did have hopelessly outclassed their Japanese counterparts which were mainly the Type 38 15 cm howitzer and Type 4 15 cm howitzer , forcing the Japanese to introduce the Type 96 15 cm Howitzer . It is interesting that some earlier pieces ( about 24 ) of sFH18 in China were designed specially with a 32 / L barrel , known as sFH18 32 / L . The maximum range was increased to 15 km . But most of the sFH18 in China were lost to attrition . Only two pieces can be seen in the museums today . Against the Soviet Union however , the sFH 18 proved to be greatly inferior to the Red Army corps artillery 122 mm gun and 152 mm ML - 20 gun - howitzer , whose maximum range of and allowed it to fire counter - battery against the sFH 18 with a and advantage . This led to numerous efforts to introduce new guns with even better performance than the ML - 20 , while various experiments were also carried out on the sFH 18 to improve its range . These led to the 15 cm sFH 18M version with a removable barrel liner and a muzzle brake that allowed a larger " special 7 " or 8 charge to be used . The 18M increased range to , but it was found that the liners suffered increased wear and the recoil system could not handle the increased loads in spite of the brake . This led to a more interesting modification , the introduction of the 15 cm R . Gr . 19 FES ammunition , which used a rocket - assisted round that could reach and give it some level of parity with the A - 19 and ML - 20 . Several countries continued fielding the sFH 18 after the war in large numbers including Czechoslovakia , Portugal and many South American and Central American countries . Finland bought 48 sFH 18 howitzers from Germany in 1940 and designated them 150 H / 40 . These guns were modernized in 1988 as the 152 H 88 , and they are still used by Finnish army .