I am trying to keep my oar out of the water on this topic (indeed, contemplating puting an oar on my shoulder and walking inland until I reach a spot where someone points to it and asks me what it is).
However, L6, could you have been possibly thinking of 'Devil's Brigade?' This starred (I think) William Holden and Vince Evans. At one point Holden, the CO of the newly formed American Canadian spec ops unit, takes a knife out of a package he got in the mail, sticks it between the desk and drawer, and pushes down on the handle with his hand. The blade snaps, and Holden disgustedly tosses it aside.
Of course, even if I am right about the movie, it was made in an unenlightened era where knives were expected to be prying tools in an emergency.
In 'Dirty Dozen' I believe they used standard bayonets. Certainly that is what 'maggot' (Telly Savalas) stabbed the young woman with.
Movies aside, perhaps some ingenious maker could provide a knife with a torque wrench like meter with a digital read out on the handle, measured in inch pounds, or inch ounces, or whatever, and guarantee the knife up to only a certain level (in the lateral plane). Just a thought.
Walt