I was using a BA encampment recently, it was rated to 15 degrees and I was sleeping in an area that was at high altitude and got down to 36 degrees at night, I barely slept that night because i was chilled to the bone the whole night. I was sleeping in a t-shirt and shorts, I think this may be the main reason I was so cold, but I was also suspicious that perhaps it is the design of the BA bag, there is no insulation on the bottom which is designed to have a pad inserted into it. I had a insulated Air Core mattress in the sleeve that night, can anyone tell me from experience why it was such a cold night for me?
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Modern civilized man, sated with artificialities and luxury, were wont, when he returns to the primeval mountains, to find among their caves his prehistoric brother, alive and unchanged. -Guido Rey