▁the ▁guns ▁by ▁having ▁them ▁fire ▁from ▁p its ▁but ▁the ▁weight ▁and ▁size ▁of ▁the ▁guns ▁were ▁excess ive ▁for ▁the ▁task ▁at ▁hand ▁since ▁pack ▁animals ▁couldn ' t ▁move ▁the ▁guns ▁in ▁the ▁tren ches ▁or ▁across ▁the ▁qu ag m ire ▁of ▁no ▁man ' s ▁land . ▁ ▁Design ▁ ▁The ▁Mort ier ▁de ▁ 7 5 ▁mod èle ▁ 1 9 1 5 ▁was ▁a ▁short - bar rel led , ▁b ree ch ▁loaded , ▁rif led ▁mort ar ▁with ▁a ▁horizontal ▁sl iding - block ▁that ▁fired ▁separate ▁loading ▁c ased ▁charges ▁and ▁project iles . ▁ ▁The ▁bar rel ▁was ▁of ▁aut of rett ed ▁mon ob lock ▁construction ▁which ▁was ▁tr unn ioned ▁while ▁the ▁sl iding - block ▁b ree ch ▁bore ▁no ▁relation ▁to ▁the ▁Nord enf elt ▁ecc ent ric ▁sc rew ▁b ree ch ▁used ▁by ▁the ▁m le ▁ 1 8 9 7 . ▁ ▁The ▁project iles ▁came ▁from ▁the ▁u bi quit ous ▁Can on ▁de ▁ 7 5 ▁mod èle ▁ 1 8 9 7 ▁while ▁the ▁cas ing ▁was ▁a ▁short ened ▁m le ▁ 1 8 9 7 ▁cas ing ▁which ▁could ▁hold ▁three ▁prop ell ant ▁charges ▁and ▁be ▁re used ▁up ▁to ▁ 5 0 ▁times . ▁▁▁ ▁By ▁varying ▁the ▁number ▁of ▁prop ell ant ▁charges ▁both ▁the ▁range ▁and ▁angle ▁of ▁impact ▁for ▁the ▁project ile ▁could ▁be ▁controlled . ▁ ▁The ▁mort ar ▁had ▁no ▁re co il