M14Dan, wow, 50,000 rounds through your Chinese M14, that is impressive! :-)
I had the opportunity to shoot a Norinco M 14 back in the mid-1990's and what was odd was the fact that the owner and partner did not feel that they had to let the barrel cool down. We were shooting Spanish .308 surplus, and the owners just kept shooting as fast as they could load it. I remember the rifle was beefy and solid, reminded me of the Mauser 98, and I could feel the heat coming from it's cooking barrel.
I inquired with the owner of the rifle that maybe he should let it cool down some, but he said "I like to shoot it fast and hot". Doesn't that cause the barrel to shoot out fast, or does the M14 use some kind of setup to allow it to be shoot hard and heavy without multiple barrel changouts?