Originally published at Notes from the bunker…. You can comment here or there.

One of the LMI decided to take advantage of the weather yesterday to do a little backyard field testing of the military 'sleep system' sleeping bags that he got off of eBay. Out where he lives it was -12 last night so this was a good opportunity to test the bag. He laid a tarp on the ground, then his groundpad and then the bag. the inner bag and outer bag were used together and then the whole thing was inside its goretex bivvy sack. He was wearing socks and longunderwear and undershirt. For headgear he was wearing a headband over his eyes so they wouldnt freeze, and a hat.

He  slept out there in the yard for about five hours. Long enough for him to get the information he needed. The bag is designed with the intent that the user will be wearing his mil-issue 'bear suit' cold weather gear, and that is factored into the bags -30 rating. Our hero was not wearing the bear suit but he said that he was able to sleep and did not feel uncomfortable. He did say that it was highly advisable to have a face mask or something to keep your face from freezing since ducking your head into the bag coccoon-style would be unwise since the moisture from your breath would make things cold in a hurry.

His summation was that at -10 the bag was fine. He has doubts about its use at -30 unless youre wearing a polypro set of underwear and/or the pile/fleece bear suit. On the other hand, this was with the bag sitting outside…not in a tent, shelter, igloo, or other enclosure that might have offered some increased warmth or protection from the cold. He said its definitely worth the $190~ he paid for it.