KeithL. The half cock is a safety of sorts. Do not carry the rifle with a shell in the chamber and the hammer all the way down. Any blow on the hammer will fire the rifle. You can use the half cock, but I usually carry mine with an empty chamber, at least until I am on a final stalk. It's like the Colt single action. It's best to carry the hammer down on an empty chamber.
To prove my point, take a primed, but otherwise empty case and chamber it. Lower the hammer to the full down position. Tap the hammer lightly with a plastic hammer or a piece of 2x4. It won't take too hard a blow to prove my point. Any sort of harder blow, could break off the half cock notch, if you choose to use it. I have heard of accidents, where the hammer has snagged on brush, and then fallen to fire a round in the chamber.
That's probably why the gunmaker's lawyers had them put that push button safety on the new Winchesters and Marlin.
Reminds me of a happening at the range last week. There was this old gentleman, I'd say about 70 or 75 years old. He was nearly in tears as the new marlin rifle his wife bought him for his birthday would not fire.
He happened to bring it to me to look at, to see if I could figure out what was wrong. It took me a while to convice him that it was that lawyer proof pushbutton safety that was preventing the gun from firing. I took it off, and the gun shot fine. It's a good thing he wasn't bear hunting.
Paul B.