The Western Mountaineering Puma MF down sleeping bag is rated for negative 25 degrees F and is a fully-featured winter sleeping bag suitable for most winter backpacking trips in the lower 48 where you can expect to experience subzero temperatures.
Like all Western Mountaineering sleeping bags, the Puma is filled with 850+ fill power goose down which has a very high warmth to weight ratio. Weighing just 3 lbs 7 oz, it’s also one of the lightest sleeping bags you can buy with this temperature rating on the market today.
Feature-wise, the Puma has two large down-filled draft tubes on either side of the zipper to block heat loss and a very comfortable draft collar that wraps around your upper chest and behind your neck to keep warm air from escaping your bag when you move around at night.
The hood is spacious and comfortable and easily fits a down or primaloft pillow if you want a little extra comfort. My model here, on leave from Warmlite, is posing with a stuffed moose. The moose is not included with the bag and must be purchased separately.
Sizewise, the regular 6 foot bag has a shoulder/hip/foot circumference of 64/55/39 inches, making it a moderately snug around the shoulders and upper body for a 200 lb man. However, I was still able to stow some damp gear in my bag to dry overnight, including my plastic boot liners and gauntlet glove liners without being overly crowded.
The Puma also compresses down to the size of a basketball in a compression sack. This is significant. If you do any winter camping or mountaineering, you know that the size of your sleeping bag is directly proportional to the size and weight of the backpack you need to carry, since it takes up about 50% of the space in your pack. I bought the Puma expressly to make it possible for me to use a 4000 cubic inch backpack that weighs under 4 lbs for winter hiking and camping instead of a 5500+ ci pack, saving myself at least 3-4 lbs of base weight in the process.
Finally, the microfiber shell on the Puma, which is what the MF stands for, rocks. It is extremely water-resistant but highly breathable and given it’s weight to performance ratio, I feel that it is a better shell for my purposes than Gore-Tex Windstopper (GWS), another shell option that WM provides for the Puma.
On my trip, last weekend, three of us slept in a double-walled multi-person tent and we had a lot of tent condensation. My companion’s bags got quite wet, but my Puma was completely dry, which I attribute to the microfiber shell and its ability to repel water. In fact, I wish that my 3 season WM Ultralite 20 was available with a microfiber shell, instead of a nylon one, since I occasionally have shelter condensation issues with it.
Microfiber shells are constructed from a tightly woven nylon or polyester with high thread counts. The Microfiber Shell made especially for Western Mountaineering has a 400 thread per inch weave making it highly water repellent, more breathable, and lighter weight than that of coated or laminated fabrics such as Gore-tex and is a good option if you expect limited contact with water such as tent condensation. Good breathability is key in a down winter bag because a build-up of perspiration will degrade the down’s lofting power on a multi-day trip. However, if you plan on sleeping in a lot of wet snow caves, then perhaps the heavier Puma GWS shell is a better choice for you.
Western Mountaineering does not permit their dealers to discount their sleeping bags, making it virtually impossible to find a price break on them.
The Puma MF is a very significant purchase, but if you’re already into winter hiking or mountaineering, you’ve hopefully already gotten over the sticker shock of buying lots of expensive gear. I consider my Puma MF to be an excellent investment and have enjoyed using it over the years.
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