Oswald in the doorway: the blog of the Oswald Innocence Campaign, by Ralph Cinque

In his Warren Commission testimony, Nick McDonald said nothing about wedging his hand in front of the moving hammer of the gun. 

Mr. McDONALD. . . . [J]ust as I got to the row where the suspect was sitting, I stopped abruptly, and turned in and told him to get on his feet. He rose immediately, bringing up both hands. He got this hand about shoulder high, his left hand shoulder high, and he got his right hand about breast high. He said, "Well, it is all over now."
As he said this, I put my left hand on his waist and then his hand went to the waist. And this hand struck me between the eyes on the bridge of the nose.
Mr. BALL. Did he cock his fist?
Mr. McDONALD. Yes, sir; knocking my cap off.
Mr. BALL. Which fist did he hit you with?
Mr. McDONALD. His left fist.
Mr. BALL. What happened then?
Mr. McDONALD. Well, whenever he knocked my hat off, any normal reaction was for me to go at him with this hand.
Mr. BALL. Right hand?
Mr. McDONALD. Yes. I went at him with this hand, and I believe I struck him on the face, but I don't know where. And with my hand, that was on his hand over the pistol.
Mr. BALL. Did you feel the pistol?
Mr. McDONALD. Yes, sir.
Mr. BALL. Which hand was -- was his right hand or his left hand on the pistol?
Mr. McDONALD. His right hand was on the pistol.
Mr. BALL. And which of your hands?
Mr. McDONALD. My left hand, at this point.
Mr. BALL. And had he withdrawn the pistol.
Mr. McDONALD. He was drawing it as I put my hand.
Mr. BALL. From his waist?
Mr. McDONALD. Yes, sir.
Mr. BALL. What happened then?
Mr. McDONALD. Well, whenever I hit him, we both fell into the seats. While we were struggling around there, with this hand on the gun --
Mr. BALL. Your left hand?
Mr. McDONALD. Yes, sir. Somehow I managed to get this hand in the action also.
Mr. BALL. Your right hand?
Mr. McDONALD. Yes, sir. Now, as we fell into the seats, I called out, "I have got him," and Officer T. A. Hutson, he came to the row behind us and grabbed Oswald around the neck. And then Officer C. T. Walker came into the row that we were in and grabbed his left arm. And Officer Ray Hawkins came to the row in front of us and grabbed him from the front.
By the time all three of these officers had got there, I had gotten my right hand on the butt of the pistol and jerked it free.
Mr. BALL. Had you felt any movement of the hammer?
Mr. McDONALD. Yes, sir. When this hand -- we went down into the seats.
Mr. BALL. When your left hand went into the seats, what happened?
Mr. McDONALD. It felt like something had grazed across my hand. I felt movement there. And that was the only movement I felt. And I heard a snap. I didn't know what it was at the time.
Mr. BALL. Was the pistol out of his waist at that time?
Mr. McDONALD. Yes, sir.
Mr. BALL. Do you know any way it was pointed?
Mr. McDONALD. Well, I believe the muzzle was toward me, because the sensation came across this way. To make a movement like that, it would have to be the cylinder or the hammer.
Mr. BALL. Across your left palm?
Mr. McDONALD. Yes, sir. And my hand was directly over the pistol in this manner. More or less the butt. But not on the butt.
Mr. BALL. What happened when you jerked the pistol free?
Mr. McDONALD. When I jerked it free, I was down in the seats with him, with my head, some reason or other, I don't know why, and when I brought the pistol out, it grazed me across the cheek here, and I put it all the way out to the aisle, holding it by the butt. I gave the pistol to Detective Bob Carroll at that point. .