Gear review: Tennier Industries Modular Sleep System (MSS) [military]

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Gear review: Tennier Industries Modular Sleep System (MSS) [military]

Post by wildcat » September 30th, 2021, 3:20 pm

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US Military Modular Sleep System
Manufacturer: Tennier Industries Incorporated; Huntsville, TN
Rating: A

Reviewed November 2021 by wildcat

The US military modular sleep system is a mummy sleeping bag kit made by Tennier Industries. Ancient tech that goes back in some form or another to the late 1980s*, but does the job and doesn't complain. It's military equipment. It's professional grade. It takes abuse and just laughs. It's also made right here in the USA. What more could you want?

Depending who you ask it's either a three, four or five-piece system if you count the stuff sacks. The base set without the sacks is a three-piece system. Basically you have a heavier intermediate-weather bag that snaps into a lighter-weight "patrol bag", which then can zip into a goretex bivouac cover. (Yes, I have the full system.) It's meant to be adapted for a wide variety of weather, environmental and combat conditions. That's why it's "modular". Heavy and bulky if you pack the whole thing -- but take only the components you'll need. If you're camping with a buddy in moderate weather (late spring/summer/early fall) then you have sleeping bags for the both of you. The bivy can even be used solo in an emergency or if you're camping in hot weather on nights when it just won't cool down. The former two pack into the smaller stuff sack to just over the size of a basketball. It fits easily into the cavernous sleeping bag compartment (yes! There actually is a use for it after all!) on my Kelty Tioga 5500 packbag with room around it to shove a Klymit air pad, its fitted sheet (uh huh, I'm "that guy") and a My Pillow packed into a Granite Gear 7-liter stuff sack.

Some people complain about the weight - the full MSS kit nominally weighs around seven pounds, of which the intermediate bag comprises over half - I've never found it to be much of an issue, but my gear's heavy anyways. If you hike with a MOLLE II ruck you probably won't even notice it beyond that monstrous ruck's ~10 pounds base weight. My very old White Stag rectangular that I camped with from about 1995 (Camp Melanoma in fifth grade) until I retired it last year weighs shy of 9 pounds (!) so you could do worse. The bivy cover barely weighs anything at all. I would guess maybe a little under a pound. Your canister stove probably outweighs it. By necessity "ultralight" backpacking is virtually out of the question for me anyways since I'm a big dude so my gear has to be correspondingly outsized. The newer "urban gray" intermediate bag (which I have) is supposed to be much lighter than the older black model, due to improvements in fill material, but still have the same temperature rating. As of this date I've never handled the black one so I can't offer any valid comparison between the two.

Anyways, pretty much all my camping is in the summer and very early fall months (late May-early Octoberish) so just the patrol bag with bivy are plenty for me. The combination is fairly warm and I tend to sleep cold. Early in August I camped at the Muddy River lahar at Mount St. Helens, weather was low 80s, overcast and a little hazy (but sunny the next day) and mid 60s that night becoming mostly clear, but it did shower for a few minutes. Shelter was a 2020 Kelty "2-man" (yeah, uh huh) Grand Mesa tent with fly installed and guyed. I was quite comfortable** in just a cotton-poly T-shirt and a Nike swim jammer. I didn't do up the bag's hood, but I usually don't anyways. I'm nominally 6'8" ~250 lb. (inadmissible in court) which is slightly out of capacity for the standard length model*** but I still found it fairly roomy. Despite the MSS being a mummy design, with it not zipped up the entire way I really didn't feel too trapped and could move my arms around freely. I imagine with the intermediate bag snapped in it would become slightly claustrophobic but still usable. You can use a sleeping bag liner with it. I don't, but I know there are people who wouldn't have it otherwise.

Temperature ratings are around 50 for the patrol/bivy combination, -10 for the intermediate alone, and -10 to -30 for the full combination. Or so I've read; I'm not a winter camper so I've never had opportunity to test those ratings.

All the parts are machine washable in home equipment, if you have one big enough. Some newer machines (like my mom's late-2020 GE GTW465ASN1WW) will easily swallow up the individual components. (Please don't go out and buy a whole new washer just for this -- chances are your existing machine will work fine, unless you're in a tiny apartment and have a correspondingly undersized washer/dryer stack.) This saves time and money since you're not running to the laundromat. Use the delicate cycle, cold wash/rinse and some nonscented/clear detergent and perhaps some borax. Hang over a drying rack for a couple days or so then tumble the bags on a no-heat cycle to restore their loft. This is a must-do if you buy used before taking it on its first trip!

Do you want one? Well, that depends. AFAIK, Tennier don't sell directly to individuals unless you order in quantity, however thousands were produced during a period of over 30 years, so they can be had readily from surplus vendors in new and used condition. (If you do try to purchase directly from Tennier, be aware that the components are listed individually and you will probably have to order in bulk, which can quickly get mucho expensivo, Señor.... of course, you could also sell your extras, issue them to your Scout patrol or give them away as gifts.) Expect to pay anywhere from $300 to $500 or more for the full set if you buy brand-new, depending on the vendor. You can get them for dirt cheap used. If you can deal with a little extra weight (see what I said a couple paragraphs earlier) then you might be able to handle an MSS. They're built around longevity and serviceability, not so much style like commercial civilian gear is. It's a time-tested and reliable system. You should get at least 10 years of heavy use out of it. It's not built around planned obsolescence, to wear out and become unserviceable after a couple years, requiring you to spend money on all new stuff like the civilian gear industry demands of you as a good patriotic American consumer. Ahem. Just make sure you like olive drab, gray or black and camouflage (which are always fashionable and never go out of style). If you intend to get one buy from a reputable surplus dealer if you can. Beware of the crappy Chinese fakes which abound on E-Bay and Amazon. The real stuff will be made by Tennier Industries Incorporated in Huntsville, TN. See the "Facts" link below for data and NSN codes.

Source: bought mine through "MarinesSellingSurvivalGear" on Amazon; recommended by some US military employees I personally know who use/d the MSS during their official duties.

Facts: ... dular.html
More opinions: ... ep-system/


* Meaning, the rest of the outdoors gear industry is pretty much unrecognisable from what it was 30-40 years ago but the MSS really hasn't changed all that much. Please don't take it the wrong way. I'm from the 80s.

** Probably would have slept even better had I given more thought about my tent's orientation on the downslope. It was a barely noticeable angle and looked more-or-less level but just enough that the blood rush into my head bugged me most of the night......

*** Tennier are rumored to have made a "long" version of the MSS designed to accomodate dudes up to 7' but they're made of unobtanium.

BOTTOM LINE: You really can't go wrong with a sleeping bag that will probably outlive your kids.

Disclaimer: My gear reviews are not "bench test" based and do not imply sponsorship or endorsement. I am not receiving any payment (or anything) from any manufacturers or vendors to write them. They are reviews based upon actual real-life situations in the outdoors. The testimonies, good or bad, are based on fact and thereby release any and all people of any liability including myself and the publishers of this website. Anyone who views this portion of the website must accept these facts and opinions as statements based on my own actual use of the product and/or service. (tl, dr: You can't sue me or Oregonhikers if you don't like what I'm saying. Suck it up and deal with it.)
Last edited by wildcat on October 1st, 2021, 7:46 am, edited 2 times in total.

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Re: Gear review: Tennier Industries Modular Sleep System (MSS) [military]

Post by Aimless » September 30th, 2021, 4:49 pm

Some people complain about the weight - the full MSS kit nominally weighs around seven pounds
Your enthusiasm is obvious. But I'm one of the ones who'd complain about the weight.

My normal sleeping system (a down-filled sleeping bag, 4" thick insulated air mattress rated R5.5, and small pillow, including stuff sacks) is very comfortable down to mid-20s and weighs 4 lbs. Even when I add in my solo tent and rainfly I'm still well under 7 lbs. A good quality down bag is pricey, but it will last for decades, so when you amortize the cost over that many years it's a good investment.

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Re: Gear review: Tennier Industries Modular Sleep System (MSS) [military]

Post by wildcat » September 30th, 2021, 6:14 pm

Strictly MHO, of course. I agree, much nicer and more efficient sleeping systems, of vastly improved design, have appeared in the meantime like the one you described. The MSS was introduced around 1988 and has changed very little since then. I figure the longevity of a properly cared-for MSS and down bag are probably close to equal.

Problem is I'm also horribly allergic to down. Even the so-called "hypoallergenic" stuff can still make my eyes water profusely.

The main advantage though of an MSS is its customisability and relatively low/er maintenance. Its weight is what it is -- can't do much about it. That seven-pound figure is for the entire 3-part kit, which is really only suitable for very cold-weather (winter) camping and would be overkill for most mid-year trips at lower elevations (=>5000 feet). The 2-part patrol bag/bivy combination maybe weighs about 3 pounds dry. Those figures are also from the ones stated on the ciehub data page, which probably got them either from Natick's testing data or perhaps from Tennier's specsheet. In reality I estimate the actual weight of the newer model MSS to be closer to 5 1/2-6 pounds assembled. I haven't weighed it myself yet but it feels like that to me. The ancient White Stag weighs a little over 8 1/2 pounds (have weighed it) and the 3-piece MSS feels significantly lighter when I lift it.

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