My father in law bought me one of these (first photo) recently. Its the Ontario Spec Plus Air Force survival knife. The blade is the same as the old Ontario leather handled survival knife I was issued in 1971. It was called the Pilots survival knife then. The new model is made of 1095 high carbon steel as was the old model. The photo below shows the new version. All in all its a very nice, well built knife. I actually like the handle on this one better. The old leather handled version was good, don't get me wrong, but in the dry Arizona climate mine shrunk and the hexagonal hammer head/pommel wiggled a bit. I soaked it for a week in neatsfoot oil and this helped for a little while but a month later it was loose again.
I modified the new one the same way I did the old model. I dulled the top edge on the front of the blade. This makes it easier to do things like draw with the blade without cutting your fingers. I never really understood why they sharpened this. Another thing is the saw back. This was made to cut through the thin magnesium-aluminum alloy skin of an aircraft. I actually used my old one to saw through a piece of palo verde but it took a long time. It would be nice if they left the back plain. There are more than enough choices for a good, portable survival saw available. As for the so called "blood grove", it aint no such thing. My quartermaster was a very knowledgeable guy and he said it was there to give the saw clearance while making curved cuts. Makes sense to me.
I did what I always do to a new knife. I took off the edge and resharpened it. The reason I do this is thus: the boys at the factory sometimes get a little carried away with the belt sander or grinder and get a little too much heat on the edge. When you remove the factory edge and resharpen, you get into new, untouched steel and your edge will be very sharp as well as durable. The edge from the factory was very sharp but there were a few spots where it was a bit rough. My resharpening took it to a mirror finish, razor sharpness. I've skinned two cedar logs with it and it still pops arm hair.
This picture show another model of an Ontario knife. I used it to show what the sheath looks like on mine. Its exactly the same. I like the double security of two handle loops. The old model has only one loop and I remember loosing mine once because of a defective snap. I did find it, fortunately, and had the quartermaster fix the sheath. (I think he just threw it away and gave me a different one.) Another difference is the old sheath had an outside pocket with a small carborundum stone. It was handy for touching up the edge but not doing a full sharpening job. The new sheath doesn't have a pocket or stone. I think I'll add a pocket somehow and through in a ferro-cerium spark rod and a diamond sharpener. The sheath is well made from heavy leather and cordura nylon
Here's a photo of the original "Pilots survival knife". Mine was dated (on the pommel) 1-71 or January 1971
This is a very good knife and I would recommend it to someone looking for a decent, moderately priced survival knife. By the way, since I got the Spec Plus, my wife decided the old Schrade Walden sheath knife is hers now. She really likes that knife!