Haven't put it to the test, but here are my thoughts: - Big Agnes Storm King 0 Sleeping Bag -650 DownTek-

Despite not having tested the bag out in the elements, I've used it at home on the floor a couple of nights, and here are my thoughts:

A reminder to anyone looking at the BA bags. There is NO insulation on the bottom of the down bags, as compressed insulation does nothing to keep you warm. This is good. This is smart. It allows for more fill on top, and cuts weight. However, keep in mind that there is also no padding under you either. Just fabric.

Also, the sleeping pad sleeve is just 20" or so across, so don't buy an extra large pad, if you want to get it in the sleeve. Personally, I prefer a larger pad, and won't worry about the sleeve.

The second you get in the bag, I start getting warm. If I had to guess, I think with a properly inflated sleeping pad, I'd be comfortable in this bag with no clothes on down to about 20-25 degrees. And colder and I'd put on a light base layer. At zero, I'd be fully dressed.

My one issue is not a problem with the bag, but my expectations. I have a zero degree synthetic bag (comfortable to 30), that is huge when rolled up. I thought the BA down bag would compress a lot more (and it does), but is still bigger than weekend "backpack" sized even after being very compressed.

This review was written in the old system and had content requirements that are different than reviews written today.