The United States M3 Lightweight Service Mask was a needed upgrade for the US military after it was found that the weight and bulk of the older M2 series service masks were unsatisfactory. The M2 series service mask had a longer 686 mm (27-inch) hose, no oronasal cup, used the MIXA1 canister, used the MIVA1 Carrier, and had a rifle skid on the lower head harness of the facepiece which was positioned mid-cheek of the facepiece. The M3 Lightweight service mask had a shorter 457 mm (18-inch) long M3 hose, addition of an oral-nasal cup to reduce lens fogging, the lighter weight M10 or M10A1 canister, a smaller M6 carrier, and the facepiece itself had the head harness tab position changed to be farther back on the facepiece which negated the need for a rifle skid.
The requirement for the M3 Lightweight Service mask was established as early as January of 1942 but wasn't finalized or standardized until later that year. Early production of the M3 saw problems with the canister assembly, the crimping of the eye-rings to the facepiece, and problems producing the M6 carrier which was the main bottleneck of the lightweight service mask. As a stopgap, while the M3's production kinks were being worked out, the M4 lightweight service mask was finalized in late 42 where they took stocks of M2A2 facepieces and converted them into Lightweight service masks configurations by giving it an oronasal cup, an 457 mm (18-inch) hose, and an M10 canister. The M4 Army Lightweight Service Mask still didn't see any major production until late 44, however. Another issue of the M3 facepiece was the installation of the nose cup within the mask which had to be carefully vulcanized in place. Firestone developed a machine that vulcanized the nose cup to the facepiece automatically, which further sped up production. It wasn't until May of 1943 when the M3 Lightweight Service Mask had worked out most of its problems and saw full-scale production by its major manufacturers. By August of that year, the M3 replaced all older service masks on the production lines. Initial procurements of the M3 face piece were molded from class b grey natural rubber, but as a result of the military's dwindling rubber supplies caused by the loss of the pacific islands to the Japanese, a synthetic rubber program began in the spring of 1943 and ending later that year with butyl actually being the most promising synthetic rubber for future procurements. Despite butyl showing the most promise, last minute changes resulted in Neoprene being chosen for mask procurement instead, so by the fall of 1943, all M3 lightweight service masks were being produced out of Neoprene exclusively. However, neoprene had one major problem. By the winter of 1944 in the European Theatre of Operations, the problems of neoprene became apparent. Neoprene had a tendency to harden or "cold set" under freezing temperatures. This made the face piece impossible to form a gas tight seal, so before donning the mask the soldier had to hold the facepiece against the body to warm it up in order to properly don the mask. This resulted in the stop gap mask, the M4-10A1-6 Army Lightweight Service Mask, to begin mass production by late 44 and early 45, and slowly replaced Neoprene M3's in the European Theatre through to the end of the war.
An M3-10A1-6 gas mask in black neoprene rubber. M6 Carrier not shown.
The M3 was manufactured by several companies such as Dryden Rubber Company, Firestone, Acushnet Processing Company, Goodyear, General, and BF Goodrich, which resulted in a variety of different shaped and styled moldings of face blanks and rubber mixtures. The variation in facepiece molds made it possible for the Universal size to fit just about anyone, but the M3 Lightweight service mask was also made in size super small and size large and will have either "SS" or "L" in place of the usual "U" for universal. There are also technically 2 other sizes associated with the Universal size. At some point it was realized that the slight differences in face pieces and manufacturing specifications resulted in some Universally sized masks to run either a little larger or a little smaller. Thus, face pieces found to be larger than it should will have an L stamped next to the U on the forehead representing the size "Large Universal" whereas for universal facepieces that were smaller than normal were stamped with an S next to the U on the forehead representing the size "Small Universal". Modifications to the nose cup such as cutting it from the top middle also altered the sizing, and could make it more compatible to whoever it was issued to if they needed such a modification to comfortably wear the service mask. Other hardware such as the M8 valve or head harness tabs had variations as well, resulting in slight differences such as color or style. The eye-lens retainer rings can also be found painted either gray or black. The hose of the lightweight mask had several variations as well, along with the procured natural rubber or synthetic rubber M3 hoses, some 457 mm (18-inch) hoses were simply recycled 686 mm (27-inch) long MII hoses which had the lower 229 mm (9-inches) cut off of it making the total length 457 mm (18-inch). Something very interesting to note, leftover 229 mm (9-inches) pieces taken from MII hoses could then be vulcanized to another leftover 9-inch piece to create an 457 mm (18-inch) long hose. As a result, two MII hoses could be made into three 457 mm (18-inch) long M3 hoses.
The M10 canister was used on early procurements of the M3 and M4 Army Lightweight service mask as well as some examples of the earlier M2 optical mask. The M10 was smaller and lighter but just as effective as the MIXA1 canister because of superior filtering components, but didn't last as long. The MIXA1 and M10 canister were both radial flow canisters, which means air flowed in from the bottom and was directed into the outer layer of the mechanical filter which lined the outer shell of the canister, and then directed into the internal charcoal canister, and finally into the inner tube which is often lined with felt, into the hose and of course through the mask into the lungs. The internal components of the M10 canister featured upgraded filtering elements, such as an asbestos bearing paper for the mechanical filter, wrapped around an internal canister of Type AS charcoal. In mid-1943, the improved Type ASC charcoal (copper-silver-chromium impregnated charcoal) replaced the older Type AS charcoal in the M10. Then, in late 1943, the M10A1 canister was introduced as an upgrade from the M10 canister. The only difference between the M10 and M10A1 was, the M10 had a volume of 275 mL for the internal charcoal canister, whereas, the M10A1 increased that volume to 340 mL for charcoal, thereby making it more effective than the M10. The M10 canisters saw use from late 1942 all the way up until it's obsoletion date in 1949, as a result, all Army lightweight service masks in use after 1949 exclusively used the M10A1 canister.
The basic kit for the Lightweight Service Mask consisted of the mask, M6 carrier, C3 waterproofing kit, two individual protective covers, a set of M1 Eyeshields, an anti-dim cloth, and either an M4 or M5 ointment kit. Earlier kits would have two early contract cellophane packed individual protective covers and an M4 ointment kit with BAL eye ointment with the rest of the kit. Later kits were given the cloth-covered tinfoil packed individual protective covers and the M5 ointment kit which was introduced around 1944. The M6 carrier has 3 internal pockets, assuming the front face of the carrier is facing you, a sealed protective cover was stored in the left-most pocket and an opened protective cover went in the middle pocket while the third rightmost pocket housed the M4 or M5 ointment kit. The eyeshields were to be placed against the pockets on the inside of the carrier under the mask. The canister went through the two loops inside of the carrier with the inlet facing the right side of the carrier. In order to properly place the mask into the carrier, the canister was flipped with the hose running along the bottom and the inlet of the canister now facing the left of the carrier, the head harness was folded into the mask and the canister was placed into the facepiece with the chin of the mask seating over the inlet valve. The carrier was then closed. The carrier could be worn on the left side of the body at the standard carry or to the front and back. If there was a threat of a chemical attack, the hook that is present on the shoulder carrying strap would be fastened to the D-ring which would bring the carrier chest height without needing to adjust the shoulder strap. The mask could then be donned and worn effectively. Early M6 carriers were dyed OD3 which was a khaki color and then later war examples will be dyed with an OD7 shade of Olive Drab. Post-war carriers were dyed with OG107 which is slightly different from OD7.
The M3 was also famous for being modified into the E6-3-7 Assault Mask and the standardized M5-11-7 Combat Service Mask by taking an unissued M3-10A1-6 facepiece, cutting off the hose stem and vulcanizing a plug over it, and modifying the side of the facepiece to have 60mm threads for the M11 canister, but because of high rejection rates did not see much production after it's standardization and the ultimate cancellation of the project.
Later iterations of the M3 and M4 were the M3A1-10A1-6 and M4A1-10A1-6 and have no difference to their regular counterparts except for the addition of the C15 outlet valve, most known for being on the M9, and was much better at protecting the valve from debris as well as having better winterization properties over the M8. No M3A1 or M4A1 masks were originally produced, all existing examples are retrofits from older M3's and M4's where they simply replaced the older M8 exhale valve with a C15. M3A1's and M4A1's will commonly be found with the white post-war C15 outlet valve cover, but possible "wartime" or even early post war examples do exist with the earlier black valve cover that lacks a pull tab. The M3 series Lightweight Service mask was issued as a standard service mask alongside the M9 and M9A1 field protective mask well into the late 1950s. Officially, the Lightweight series were obsoleted on August 18, 1961.
Variants:[]
- M3-10-6: Versions that have the earlier M10 service canister
- M3-10A1-6: The most common variant of the mask, features an M3 facepiece made of either Black Neoprene or Grey Natural Rubber, an M8 Outlet Valve, M3 Lightweight Hose, M6 Carrier Bag, M7 Head Harness, and an M10A1 Filter Canister as the main components.
- M3A1-10A1-6: A lesser common variant of the M3 series. Same as the M3-10A1-6, but features a C15 Outlet Valve in place of the more typical M8.
More Photos:[]
_(3).JPG "M3-10A1-6 Army Lightweight Service Mask (Neoprene) (3).JPG (287 KB)")
