Iv’e been inside the depository...looking down to the street changed my perspective on how difficult the shot had been..I remember thinking that I could have hit him from up there with a good fastball. I have limited shooting skills but it still did not look very far when you consider that Oswald had a sniper badge..
At that distance, with something to lean on, I'd give myself a 50-50 chance of hitting someone in an open, slow-moving car, with my sidearm.
For a trained rifle marksman, with a scope, it was a 'piece of cake' shot.
Oswald did not have a military sniper rating. He shot Marksman in the Marine Corps, IIRC. While Marine Corps marksmanship standards are quite high, Marksman is the lowest of the three possible awards for rifle marksmanship. In ascending order- Marksman, Sharpshooter and Expert. To my knowledge, the Scout/Sniper school won't even look at you unless you shoot Expert. I'm not even sure that the Marine Corps had a sniper program when Oswald was in. Captain Land had to pretty much start from scratch creating a sniper program not much after Oswald's time in, in the 60s.
There is also no distinguishing badge for Marine Snipers.