M-65 Jacket Liner warmth comparison

I found it to be a little warmer than a LS polyester t-shirt plus a 100 wt polar fleece "expedition weight" long-johns top – but only about 1/2 – 2/3 as warm as a 200 wt polar fleece jacket.

Hi: There is a lot of market demand amongst the military for a P-loft jacket liner that can look like a M-65 but be much warmer; Brigade Quartermaster has many versions. So my guess is that the M-65 is much less warm than commercial Primaloft jackets—my MEC p-loft jacket is the equivalent warmth to 400 wt polyester pile by personal experience, sorry I have no CLO values to share!

I used to love my "woobie", as we called them. That is until I did anything active with it one. They don't breathe at all and you get that ohhh so wonderful clammy feeling after any amount of physical exertion. Also keep in mind anything issued to the military is made by the lowest bidder so the materials aren't exactly the best.

M-65 Jacket Liner Warmth Comparison

The US Military’s insulation value specifications, for the various components of their ECWCS, are listed in the following table. I added the columns for the jacket and pants.

A M-65 jacket liner, $6.98 and 10 oz, is between the warmth of a Polartec 300 jacket (.92 clo) and a Patagonia PO (1.06 clo). The Polartec 300 and Patagonia PO clo values are from my laboratory test chart previously posted to this forum.

I'm sure going to have to push this to my new Scouts.

Thank you, everyone, and especially you, Richard. Your posts have been most instructive and very appreciated.