Just got a USMC sleeping Bag in LONG size (for "6 foot or taller"); tag on outside of foot.  Coyote brown exterior, green interior; not likely reversible, but unsure about that.  Seems about same weight as lightweight Army MSS "Patrol" bag, but the two systems are not fully compatible, as the Army system relies on snaps for attaching all the components, and lining-up all the zippers, while the USMC system relies on rubber "bungee" loops sewn onto the OUTSIDE of the USMC bag to interface with snapped loops on the INSIDE of the USMC bivvy.

There's a 1' wide nylon webbing loop sewn into the foot of the bag, possibly for hanging it for drying/venting.  Would appreciate info about this.

Someone wishing to modify their black Army Patrol bag to be compatible with the USMC bivvy could sew some loops in the right spots on exterior of patrol bag, so as to match the snapped loops inside the USMC bivvy.  That would ensure the zippers/closures all lined up.

Single 1/2 length central ventral zipper (plastic/small-toothed) with decent length internal and external zipper pulls.  There is a sort of"wind barrier" over the zipper, but poorly done, IMHO.  NO auxiliary closures for the bag should the small-toothed, plastic zipper fail----and the zipper can definitely "snag" on the internal lining of the bag, as I just found out. There is a bungee cord around the face opening with a cord-lock adjustment at the top/forehead of the face opening.  One may have to partially open the zipper of the bag to fine-tune the bungee adjustment.

Plastic snaps near the "neck" of the bag, one female on a "tab", and two stationary male snaps.  IDK how durable they might be, nor how useful.  If they fail, remove them all, and replace with common all-brass snaps of same size.  Given the thinness of the material in which these OEM snaps are set, gluing some additional material onto the bag/tab where these OEM snaps are emplaced might be a good idea.

Bag itself is very likely NOT water-resistant, at least by the time most of us get a surplus item, so suggest when laundering the bag, use proper chemicals for laundering, rinse 3X, and then consider applying appropriate "rinse-in" waterproofing chems.  Using proper "rinse-in" waterproofing chems on the bag ought not impede its breathability.

FWIW, USMC sleeping bag ensemble includes a mesh bag which supposedly will contain both bag+bivvy.  Not a bad idea, as the mesh bag will allow a limited amount of venting/evap of water on the items.  Not perfect, but not a bad idea, either; depends on how durable the mesh bag is.

Gently rinsed a little grime/finger grease from a couple spots on the USMC bag, and currently tumbling it on LOW heat in clothes dryer, reversing it inside-out second time.

See USMC Bivvy Initial Review:  https://www.ar15.com/forums/armory/USMC-Bivvy-Sack-Initial-Review/10-535806/?page=1

Can't speak as to upper/lower temp levels for the USMC sleeping bag, but unless the USMC bag and/or the Army Patrol bag has some sort of whiz-bang synthetic insulation, USMC sleeping bag is probably comparable to the Army Patrol bag.

USMC General System Info (1-70):  https://www.trngcmd.marines.mil/Portals/207/Docs/FMTBE/Student%20Materials/FMSO%20Manual/105.pdf

Link is dead. Is this the 3 part sleeping system bag? Slept in that one for a lonnnnnng time! All ya need now is a Fly for it!

Fixed link, kinda.  AFAIK, the USMC sleeping system consist of: "3-season" sleeping bag, bivvy sack, mesh storage bag, solid nylon storage bag, and what appears to be a 3/4 length sleeping pad.

I could be wrong about "some" of the items being "officially" included within the USMC system, so listing all pertinent items.

I'd be obliged if someone can send me a current link to the instruction Manual for the USMC Sleeping System, or whatever it is called.

ARMY MSS has a light Patrol Bag, an Intermediate bag (either of which can be used seperately, or fastened together for cold weather), a bivvy sack, a compression sack, and possibly a sleeping pad.  

Army has also issued in the past some heavy fleece cold-weather sleeping boots, mitts, and a head-cover.  IDK if USMC has issued similar items.

Don't claim to be an Expert, just relaying info as I get it, along with some personal observations and comparisons of items with gear that I own.

I have some saved images of the USMC sleep system instructions but they are hard to read. Its the only piece of the 3S system I am missing.

I've kept my components in the mesh bag in my vehicle. It has held up quite well - no tears or other issues.

While searching I found the training video. Until finding it I was unaware of the additional cold weather portion of the system.

Marine Corps Sleep System Training Video:

Very informative vid, and thanks for posting it.

To return the favor, herea link to a New waterproof stuff sack and a manual: Link

I was interested in the USMC system primarily due to the bug netting on the bivvy sack; I wanted to see how it was made and whether I could fab something similar for Army bivvy sack.  Bought the Long USMC "patrol" bag for added utility.

Could probably be done by someone with a lot more machine-sewing and fab skills than I currently have.   I have "in my mind" the basic outline of how the thing should be made and attached to the bag with snaps.  @Diz

Since the Army Patrol bag can have couple of loops added (hand-sewn) to it in order to ensure all the zippers (bivvy and bag) are lined-up, I don't think most people need to rush out and buy the USMC "patrol" bag, unless it's on account of the size/length of the bag being an issue

TLDR: Perhaps use of Hyperlink Icon would help out?

Before I saw that video last night I'd not known that only the long size bags have a green interior.

Thanks for the auction link - I had seen that listing before. It gave me a thought that I need to first check the pocket of my waterproof stuff sack in case one is there that I didn't notice.

The netted portion of the USMC bivy bag is what initially interested me as well.

The challenge was finding one that didn't have cigarette burn holes in the netting.

I found a really nice used bivy with a perfect net and never looked back. I think the flexible wire to keep the net off one's face it a really intelligent design feature.

The only time I've tested the bivy's water resistant capabilities was in a buddy's leaky tent in a hunting camp. I was dry and warm - he wasn't.

Now I'm interested in the winter bag add-on.

This vendor has different grades of the bag you're looking for; the one linked is the best grade.  "One size fits all"  Link