“With the emergence of the M16 as the principal infantry arm of the US ground combat forces in South Vietnam, the major thrust of suppressor development was centered on the 5.56mm rifle. The USAMTU had been actively involved with suppressor testing during the course of Army revaluations. So far as the AMTU was concerned, if there were certain benefits to be gained by field use of a suppressor-equipped M16 rifle, then fitting a similar device to an accurized rifle “offered endless possibilities” for combat use in Vietnam. ” -Senich
While suppressed guns had been used in past wars ,their use and development during the war in Vietnam was the golden age of silencers in use as more than assassinations or sabotage special missions. The effectiveness of long range fire on enemy at night or day light with out being able to determine true range or direction can not be questioned . The impact of the effectiveness of knowing friendly troops have suppressor equipped rifles even has an effect to their fellow soldiers. “ I would see these guys from time to time, they would come in just after first light and I couldn’t help thinking how damn glad I was they were on our side” To many US troops the sight of other US combat personnel with suppressed rifles made and impression.
Even though rack grade M16s with suppressors had been issued for specialized units for covert missions and regular forces for long range patrols, recon, and ambush missions no official organized program existed for fielding optic equipped suppressed M16s. Examples of M16s with optics and suppressors are seen in many pictures, but usually this was an example of individual initiative or small units going about it in a quasi official manner.
Official documents from as early as May 1966 show that a program to field suppressed M16s to RVN had began. The USARV submitted an ENSURE request for “silencers for the M16A1rifle.” Even so, it took a considerable amount of time before examples were sent to RVN for combat testing.
Most of the examples sent to VN for testing and use are the US Army Human Engineering Lab, Frankford Arsenal and Scionics inc. After testing it was concluded that all models did reduce a noticeable amount of muzzle noise from the M16, they all also came with issues and an increased in cleaning.
During the testing and fielding it did not take long for users to bring up the idea of sub sonic ammunition to increase the effectivness of noise reduction. From the book by Gary Douglas , A LRRP’s Narrative.
” I let Crowe carry my M16 with silencer. We had a number of 556mm rounds bootlegged, using low velocity powder and soft lead bullets that did make the suppressor quite effective .. The lead bullets worked fine, except for the one drawback. You had to hand cycle each round. “
Of course making sub sonic ammo is well thing the means of ammo producers or handloaders but making sub sonic ammo that would cycle the action of the rifle is another matter Not to mention the obvious requirement for effective terminal performance and range. One problem encountered was with making sub sonic ammo was the now empty space inside the case. They found quickly that if the bore was pointed down, the powder would fall to the front of the case away from the primer resulting in failure of ignition or delayed ignition.
“A concerted effort was made to develop suitable subsonic ammunition. However, a major problem came as a result of the reduced powder loading. When the M16 round was down loaded there was only a small amount of powder in the case, When the weapon was angled downward the powder showed the tendacy to move forward in the case, away from the primer and ignition was either irregular or nonexistent. I was necessary to emply filler on top of the powder charge, Numerous substance such as oatmeal, cream of wheat, and cotton were tried; all with disastrous results. After firing a few rounds the rifle gas port and suppressor became clogged with the inert filler.” Donald G Thomas -Scionics
The method to finally cure this was to use an epoxy inserted into the case in a way that left a small central cavity for the powder. An effective but very time consuming and expensive. The end result being that the vast majority of suppressors used and issued during the war were used with standard service ammunition.
By the end of the War , the Scionics MAW-A1 suppressor was the model deemed the most suitable and durable for use on the M16 rifle.
The suppressed M16 became a very effective tool for operations in South Vietnam, especially for small recon teams. My mentor served in a ranger company on LRRP missions in the 199th Brigade and carried a suppressed M16. He tells of ambushing a group of Viet Cong one night while cooking their dinner.
” They were about 5o yards away and it was almost night . They were sitting around a fire cooking and smoking dope. One had his back to me and I shot him in the back of the head. He immediately fell over onto the fire and the look on the faces of his friends was pure terror. The shock of being sprayed with their buddies head, not hearing the shot and being stoned really took its toll Then the rest of the team opened up on them “
He was made more or less the team sniper and liked the suppressor and M16 combo. He did say that in an emergency fight he had to fire on full auto and at a certain point the suppressor blew off the end of the barrel and “took off like a rocket”.
The Army would take some time before getting serious about suppressing M16 family of weapons for general or sniping use. It went on to focus on the Xm21 system and a suppressor for it. This combining 762mm semi auto rifles and suppressors of course went on to be more fully realized in the M110.
The concept of the M16 with suppressor was and is just too good to die. The military went on to field the KAC NT4 suppressor for the M4 and MK18 carbines. The with the more perfected idea from Vietnam of the M16 with suppressor in the excellent MK12 special purposes rifle using the Opcs inc. suppressor. Perhaps what many user in the Vietnam wished for.
All of the previous systems are no longer used or being phased out of and being replaced with newer designs. But the AMTU’s idea of a suppressed M16 is still as valid and useful as it was in the 60s.