With no explanation, label text_A→text_B with either "not_related" or "related".
text_A: Dungeons & Dragons was written by Gary Gygax and Dave Arneson.
text_B: The 22.5 cm Minenwerfer M 15 was a heavy mortar used by Austria-Hungary in World War I .. World War I. World War I. mortar. Mortar ( weapon ). Austria-Hungary. Austria-Hungary. It was developed by Bohler as an alternative to the German Ehrhardt 25 cm schwere Minenwerfer which Bohler was having problems building under license .. Bohler. Bohler. Ehrhardt. Rheinmetall. 25 cm schwere Minenwerfer. 25 cm schwere Minenwerfer. It was a muzzle-loading , smooth-bore mortar that had no recoil system whatsoever .. mortar. Mortar ( weapon ). The entire mortar had to be levered around to aim at new targets .. mortar. Mortar ( weapon ). It was not particularly accurate and bombs often fell over in flight and landed on their sides which caused a lot of duds in soft ground .. It fired high-explosive and gas shells .. high-explosive. high-explosive. For transport two wheels from the Gebirgsgechutz M 99 were used .. The M 17 version of this weapon had an elevation screw with a double thread and reinforced trunnion bearings .. trunnion. trunnion. It 's unclear how the M 16 differed from the earlier model .
not_related.