Hi,
Just for reference I had posted back in 07' when we had to re-string the M819 after the old wire failed during use. It used 105ft. of 9/16" dia. 6 x 19 fiber core wire rope with a nominal strength of 33,000lbs. It had 9/16" dia. before and the pulleys on the boom and sheave match the wire rope dia. I'm sure you could put a little more length on the drum if you wanted to.
It wasn't that bad of a job. There's a wedge in the drum that holds the wire. We had purchased a 400' reel and one end had a finished termination.
See attached pics of comparison between old and new terminations as well as how the wire rope seats in the pulleys.
(new on left, old on right)