Recently removed a damper from a 312 and it was snug.  Sent it to Damper Dudes (highly recommend) and they made it new again.  Wanted to be careful putting the damper on since it felt snug by hand.  Got about an 8" piece of steel all-thread that was the same as the crank bolt (can't remember threads off the top of my head).  Slid the damper on the crank snout (with grease), threaded the all-thread into the crank, slid a crank washer and short piece of pipe and another washer on the all-thread.  Ran a nut down to the pipe and put double nuts (tightened together) on the end to hold the all-thread.  Twisted the nut by the pipe the pipe to apply pressure while holding the nuts on the end.  Damper went on with no drama and the all-thread protected the threads in the crank.  Something to consider.