7.62 x 51mm - .308 win usage?

i have heard that you may run into a problem when shooting commercial .308 in old military rifles chambered for 7.62 nato. is the same true when shooting 7.62 nato in a rifle chambered for .308 win. from what i have read the main problem is case stretching in the longer chambered military rifles and the case failing. i do not believe from what i have read i will have a problem in a short chambered rifle designed to use .308. if anyone has anything to add please let me know i am just wanting to confirm my thought and make sure i have fully understood what ihave read about the ammo.