Modular Sleep System (MSS)

(History of the Military Issued Sleeping bag)

By: William McKinney

President, Bradley’s Military Enterprises

The Down Filled Intermediate & ECW Sleeping Systems: When I was a young private back in 1982 soldiers were issued 2 different types of military sleeping bags.  Both models were made of cotton with goose down insulation.  In Babenhausen Germany it was cold during the winter, and we were issued the Extreme Cold Weather (ECW) model.  I don't know if this is factual, but I was told the ECW sleeping bag had a -30F temperature rating.  The other model I was issued in Ft. Hood Texas was an Intermediate Cold Weather sleeping bag.  I was told this had a 10F rating.  Both models looked identical from the outside, but the ECW model was thicker than the intermediate bag.  With this being said I wouldn't be able to differentiate a tightly rolled ECW bag from a loosely rolled intermediate model.  The easiest way to determine which model you were issued was to look at the bold printed writing on foot of the sleeping bag.  You could also look inside of the sleeping bag at the label.  Both approaches would identify the type of sleeping bag you have.  Here are some of my thoughts about the military's intermediate and ECW down filled sleeping bags:

• Both bags are relatively warm. I feel the older down filled intermediate and ECW sleeping bags are warmer than their modern counterparts.
• The tie strings at the foot of the down filled bag are practical for rolling up the sleep system, but it is grossly inferior to the modern day stuff sack.
• The older down filled models are heavy and bulky when compared to the modern day modular sleep system.
• The newer modular system with its clever compression sack compacts smaller and stores away significantly better than down filled bags. During the down filled sleeping bag era the military didn't issue rucksacks with built in sleeping bag carriers. We placed our sleeping bag inside of a wet weather bag and used spaghetti or tie down straps to hold the sleep system to the bottom of a LC-2 rucksack. This was a poorly designed approach. The sleeping bag would bounce about continuously. The modular sleep system, on the other hand, compacts tightly using a compression sack, and it fits snuggly into the sleeping bag carrier of a Molle Ruck System. This modern approach is light years superior to the methods used in the good old days.
• If an older down filled sleeping bag got wet it was heavy, and it took forever to dry. The modular sleep system is lighter, dries faster and it is less prone to get wet due to the attachable Gore-Tex cover or "bivey cover."
• With the exception of being warmer the older sleeping bag models are grossly inferior to the modular sleep system issued today.

The newer modular system with its clever compression sack compacts smaller and stores away significantly better than down filled bags. During the down filled sleeping bag era the military didn't issue rucksacks with built in sleeping bag carriers. We placed our sleeping bag inside of a wet weather bag and used spaghetti or tie down straps to hold the sleep system to the bottom of a LC-2 rucksack. This was a poorly designed approach. The sleeping bag would bounce about continuously. The modular sleep system, on the other hand, compacts tightly using a compression sack, and it fits snuggly into the sleeping bag carrier of a Molle Ruck System. This modern approach is light years superior to the methods used in the good old days.

• If an older down filled sleeping bag got wet it was heavy, and it took forever to dry. The modular sleep system is lighter, dries faster and it is less prone to get wet due to the attachable Gore-Tex cover or "bivey cover."
• With the exception of being warmer the older sleeping bag models are grossly inferior to the modular sleep system issued today.

Generation I:  The  2-piece Gore-Tex Sleeping Bag System:

This sleeping system consisted of the following parts:

• A brown intermediate cold weather sleeping bag made of nylon rip stop material and continuous filament polyester insulation. The sleeping bag could be zippered closed or use garment snaps. There are additional snaps on the intermediate sleep system that allows a Gore-Tex cover to be directly attached over the bag. A draw cord allows the hood of the mummy bag to be open wider or closed tighter. In later models the intermediate bag was offered in solid green.
• As previously mentioned there is a Gore-Tex cover that could be attached to the intermediate sleeping bag. Officially this item is known as a bivey cover. In the earlier models the top of the cover used woodland camouflage material and the bottom was brown. Later bivey covers were completely covered in woodland camo.
• The system included a brown nylon compression sack that tightened from the side. The sleeping bag and cover would be placed inside of this sack, and it would substantially compress the contents down in size for better storage.

In the early 1990 era I was introduced to the Gore-Tex sleeping bag system.  I was immediately impressed with how light the system felt.  I was especially impressed with the introduction  of the compression sack, but I seriously questioned the warmth of the system.  When I attended distant gun shows during this period, I used the 2-piece system regularly in the back of our company cube truck.  As I suspected this 2 piece model wasn't very warm when the temperature fell below freezing.  Therefore, I used the older down filled ECW model during the heart of winter and used the 2-piece Gore-Tex model during the warmer months.  Here are some of my summarized thoughts about the older 2-piece Gore-Tex sleeping bag system:

• The system was significantly lighter than the older down filled models.
• The feel of the nylon was more comfortable on the skin.
• The Gore-Tex cover was an outstanding concept. This would increase warmth and dryness while keeping the weight of the system light.
• The 2-piece sleeping bag is the lightest sleep system ever issued by the military.
• I have been told this system has a 10F temperature rating. With this being said during the peak of a brutal winter, the system is not effective at keeping you warm. It would be fine in Texas, but it sorely lacked enough insulation here in Northern New York.

  Generation II:  The  3-piece Gore-Tex Sleeping Bag System:

This sleeping system consisted of the following parts:

• A thin green patrol bag made of rip stop nylon and polyester insulation. This thin sleeping bag uses a zipper and has a garment snap backup system. The patrol bag can be used by itself or snapped into the intermediate sleep system.
• A thicker black intermediate cold weather sleeping bag made of nylon rip stop material and continuous filament polyester insulation. The sleeping bag could be zippered closed or use garment snaps. There are additional snaps on the intermediate sleep system that allows a Gore-Tex cover to be directly attached over the bag. A draw cord allows the hood of the mummy bag to be open wider or closed tighter.
• As previously mentioned there is a Gore-Tex cover that could be attached to the intermediate sleeping bag. This "bivey cover" is completely surrounded in woodland camouflage.
• The system included a black nylon compression sack that tightened from the top. The patrol bag, intermediate bags and cover would all be placed inside of this sack, and it would substantially compress the contents down in size for better storage.

The 3-piece Gore-Tex sleeping bag system is superior to the 2 piece model, and it addresses the major shortcoming of the older model.  This newer sleep system provides adequate warmth.  Used in combination with all of the parts, the addition of the patrol bag adds enough warmth to make life bearable under extreme cold weather conditions. I want to express that I like the modular concept of this sleeping bag system and how the different bags can be used together or independently.  The thin patrol bag is ideal for summer use.  The intermediate bag is ideal for use in late spring or early fall.  When the patrol bag, intermediate bag and Gore-Tex cover are all attached it provides sufficient warmth in most winter conditions.  Although this sleeping system is rated to -30F, personally  I wouldn't want to use it if it fell below 10F.  I will confess that my tolerance to cold weather is significantly less than the average person and far less than the average infantry soldier.  The good news is that the 3-peice model is warmer and more practical than the older 2-piece model.   Here are my summarized thoughts about the 3-piece sleeping system:

• The major improvement of the 3-piece system is the introduction of the patrol bag. This thin sleeping bag is ideal for summer use, and it improves the warmth of the complete system for winter use.
• The next biggest improvement is the compression sack. The top tightening approach is superior than using the side compression approach. By adding pressure with your knee at the top of the sack you can compress the contents much tighter than before.

  Generation III:  The Universal Camouflage Modular Sleep System:

• Gore-Tex BIVY outer cover bag 60 F (1.5 lbs)
• Patrol Sleeping Bag 30 to 50 F (3 lbs)
• Intermediate Cold Weather Sleeping Bag 30 to -10 F (4 lbs)
• Large Compression Stuff Sack
• Small Compression Stuff Sack
• The completely integrated system is rated to -30 F when the user wears the expedition weight polypropylene shirt, drawers and issue cushion sole woolen socks.
• To obtain lower temperature ratings, additional layers of Extreme Cold Weather Clothing articles must be added to the user's clothing ensemble inside the sleeping bag.
• The sleeping bag laid out measures 96", 34" at the shoulders, and 5x7 packed.

The MSS consists of a camouflaged, waterproof, breathable Gore-Tex bivy cover, a lightweight patrol sleeping bag, and an intermediate cold weather sleeping bag. 2 compression sacks are included to store and carry the system. The MSS is available in colors compatible with the universal camouflage pattern. The patrol bag provides cold weather protection from 35 to 50 degrees Fahrenheit. The intermediate bag provides cold weather protection from minus 5 to 35 degrees Fahrenheit. Together, the patrol bag and intermediate bags provide extreme cold weather protection in temperatures as low as minus 30 degrees Fahrenheit. The bivy cover can be used with each of three MSS configurations (patrol, intermediate, or combined) to be comparable with the environment in which the system is being used; the bivy cover provides environmental protection from wind and water. Sleeping bags are made of rip stop nylon fabrics and continuous filament polyester insulation; camouflage bivy cover is made with waterproof, breathable, coated or laminated nylon fabric called Gore-Tex; the compression sacks are made with water-resistant, durable nylon fabric. This system is very similar to the older 3-piece system with the exception that the bivy cover comes in universal camouflage pattern with matching color tones with the patrol & intermediate bags.  The most noticeable improvement was made to the compression sack.  Rather than 1 larger compression sack used with the older models the newest system has 2 sacks.  The compression sacks have 2 sizes.  The smaller size is used for independent use of the patrol bag, and the larger sack is used with independent use of the intermediate bag  The 2 compression sacks attach to one another and house the complete system. Other Thoughts:

• When the average soldier refers to their 2-piece or 3-piece systems they are not including the compression sack. I think it would be less confusing if the compression sacks were included in the description. If this were the case the Army has issued 3, 4 and 5-piece sleeping systems. Some people do use this description all though it is not an official title.
• Although I have mentioned that I wouldn't use this sleeping system under 10F keep in mind I have little tolerance to cold weather, and I like to "sniffle."
• Due to its light weight, water resistant and highly compactable features this sleeping bag is ideal for many outdoorsmen and survivalists. It is well suited for many civilian applications.

Summary: I'm impressed with the improvements the Army has made to its individual soldier equipment.  The modular sleep system, more commonly known as the Gore-Tex sleeping bag is no exception.  This is a good light weight piece of equipment that stores away well into any backpack.  I encourage serious hunters or hardcore survivalists to take a look at the MSS sleeping bag.  I anticipate it will take care of the needs of many of my customers. Sincerely;   William G. McKinney Bradley's Military Enterprises President