there is no danger to the rifle using 165 gr loads. the M14 family is designed to operate within it's optimum range using 147 gr up to 174gr...... my hunting bullet of choice in .308 for black bear and moose is the 165 gr nosler partition.
for bullet weights outside the designed parameters, shutting off the gas system is adviseable.
here's where it gets interesting...... for those with M1A rifles or chinese rifles with U.S. made gas cylinders(usgi,SAI, SEI ) you can purchase a SADLAK , NM "GROOVED" piston and studies have shown that bullet weights up to 200 gr are now possible..... as this piston allows a specific amount of piston blow by that expends the recoil energy/gasses and prevents damage to the rifles action.
150gr will get the job done...... but an extra 15 gr's wouldn't hurt either.... my vote goes to the 165gr for elk, moose, black bear, cariboo and the 150 gr for deer , antelope and wild boar.