, ▁or ▁can ▁be ▁dropped ▁by ▁par ach ute ▁with ▁air bor ne ▁units . ▁When ▁emp la ced , ▁the ▁how itzer ' s ▁high ▁volume ▁of ▁fire ▁compens ates ▁in ▁large ▁measure ▁for ▁the ▁lower ▁explos ive ▁weight ▁of ▁the ▁project ile ▁compared ▁to ▁the ▁Army ' s ▁ 1 5 5   mm ▁and ▁ 8 - inch ▁how itz ers . ▁Since ▁ 1 9 6 4 , ▁the ▁Army ▁acquired ▁ 1 , 1 5 0 ▁M 1 0 2 ▁to wed ▁how itz ers . ▁The ▁weapon ▁is ▁being ▁replaced ▁by ▁the ▁M 1 1 9 - series ▁ 1 0 5   mm ▁how itzer . ▁ ▁Res istance ▁to ▁change ▁ ▁Units ▁were ▁initially ▁equ ipped ▁with ▁the ▁M 1 0 1 A 1 ▁how itzer , ▁virt ually ▁the ▁same ▁ 1 0 5   mm ▁how itzer ▁that ▁had ▁been ▁used ▁to ▁support ▁U . S . ▁forces ▁since ▁World ▁War ▁II . ▁In ▁ 1 9 6 6 ▁a ▁new ▁ 1 0 5   mm ▁to wed ▁how itzer , ▁the ▁M 1 0 2 , ▁was ▁received ▁in ▁Vietnam . ▁The ▁first ▁M 1 0 2 s ▁were ▁issued ▁to ▁the ▁ 1 st ▁Battalion , ▁ 2 1 st ▁Field ▁Art illery , ▁in ▁March ▁ 1 9 6 6 . ▁Rep lacement ▁of ▁the ▁old ▁how itz ers ▁continued ▁stead ily ▁over ▁the ▁next ▁four ▁years . ▁ ▁Many ▁of ▁the ▁more ▁season ed ▁art illery men ▁did