Rating: 3 / 5
Just had to try this gear out. It is 3.5 lbs. so it is not UL. But the hood is detachable, wool lined, syn. fur lined with a wire inside to shape the hood, velcro attachment under the chin, and size adjustment lines inside the hood.
It is hot in 35 F weather, when I tried it out in the picture.
Lining is some kind of synthetic. It cost $25 used and in excellent shape from a surplus dealer here in N. Cal. over the Internet.
Main goal in owning this is to learn to use a hood with fur lining on the outter edge in heavy weather, snow and cold. Now all I gotta do is wait for the snow, since the weather front changed and the snow level lifted -- had been expected to snow the next four days, but doesn't look like it now. Phooey.
Jacket is extra long and was designed to be worn over a pack in the back, so this is a small and I can wear a medium or large usually. Jacket has waist level draw cord and bottom bungy cord draw string, two hand warming pockets that are very deep, could hold enough UL gear for an overnight. The lining unbuttons and comes out -- it is a synthetic lining that is effective, as far as I can tell.
Its history goes back to 1951 and the Korean War and cold weather, sub-zero. It was made in the same configuration until 1965, according to the Internet sites devoted to it. In 1965 the materials were upgraded to better synthetics in the body and hood, or so the web sites say.
What is funny is it was a favorite piece of clothing for the Mods in England and was worn by musicians like the Who. It is, therefore, a collectors item in Britain. There is even an entire web site devoted to it and unused M51s are being sold for as much as 400 British Pounds, at least that is what the web sites say.
So this gets a 3 for being fun, and my first blizzard jacket & hood w/fur lining (synthetic), and because it made the postmistress and my partner laugh their heads off when I tried it on in the post office today.
Initially I had given this a 5, but on reading the Reader Review page the criteria for a rating are a ratio of performance to weight. And, this is not a UL piece of gear IMO at 3.5 lbs. Therefore, I wouldn't want someone to run out and buy it thinking it was a piece of UL or L backpacking gear. Also, it is old technology so there are not only lighter but, IMO, funcitonally better choices available.
Its serious use will be as safety gear in our Explorer or Subaru when the weather is bad and cold. It will be stuffed in the back of the vehicle with the kitty litter for icy conditions, the emergency bivvy/heat blankets, first aid gear, flares, tools, battery cables, shovel, and most recent edition of the BPL magazine.