adopted in 1959 in army service, the m67 was used in the vietnam war together with the much larger 105 mm m40. the m67 proved an effective weapon, though it was primarily used against personnel in combat, and saw little or no use against armor and even against fortifications. while troops praised its effectiveness, the m67 came under heavy criticism due to the weapon's weight and length as well as its backblast, which often precluded its use in offensive operations. because of these disadvantages, the marine corps units continued to use the old m20 "super bazooka" in preference to the m67. it was largely replaced in army service by the m47 dragon anti-tank missile system starting in 1975. the m67 was also issued to anti-armour platoons of 1 atf (australian/new zealand task force) during the vietnam war, being used near the perimeter of the defense bases due to its weight. the m67 was issued in lieu of the standard issue carl gustav for these armies. this may have been to simplify logistics, or it may be that ammunition for the carl gustav could not be sourced due to swedish opposition to the war in vietnam.