I had two problems with my m14 while in the Army.
One, I had a FTF and reached my thumb down into the receiver to straighten out the round in top of the mag and ended up with an m14 version of 'm1 thumb'. It was bloody.
Next when I first got the m14 in basic and we went to the range, the first firing went like this:
We lined up on the range and were told we would fire one round.
RO says ,over the loudspeaker: 'Ready on the left, ready on the right, the firing line is ready ! Fire ONE round !
I aim, pull the trigger and boom boom boom boom boom, 4 rounds downrange in about 1 second.
The DI comes over and chews my ass. I explain I only pulled the trigger once. He screams "one, ONE ROUND"
RO says ,over the loudspeaker: 'Ready on the left, ready on the right, the firing line is ready ! Fire ONE round !
I aim, pull the trigger and boom boom boom boom boom, 4 rounds downrange in about 1 second.
The DI comes over and chews my ass. I explain I only pulled the trigger once. He screams "I told you ONE ROUND". I explain the rifle is malfunctioning. What do I do? I've only got 20 rounds in the mag and they'll be gone after five shots. He says do the best you can.
RO says ,over the loudspeaker: 'Ready on the left, ready on the right, the firing line is ready ! Fire ONE round !
I aim, pull the trigger and boom boom boom boom boom, 4 rounds downrange in about 1 second.
The DI gives me a dirty look and we take a lunch break.
As we break, we stack all the rifles in a rack. While everyone is eating, I swap the trigger group from my gun with the one next to mine.
After lunch:
RO says ,over the loudspeaker: 'Ready on the left, ready on the right, the firing line is ready ! Fire ONE round !
I pull the trigger, Boom !
At the other end of the firing line, I hear, boom boom boom boom boom !
I qualified expert, don't know about the other guy.
[oops] [roll]
Those are the only two problems I ever had with an M14, and I've had no trouble at all with my M1, even though I've only put about 1000 rounds thru it. I'd guess, being made in 1944, it's had a few through it.