The main problem you will run into is OAL. In order to load a 165gr spire point .308 bullet into a 30-30 with the correct OAL, the bullet will be too far in the case, that is, the ogive will start below the case mouth.... If your chamber will allow you to load long, it is possible, but IMO, its not a good idea... Almost as bad an idea as buying a single shot 30-30....
To me, the 30-30 round makes no sense unless you are going to use it in a levergun....