Last year, my HN comments ranged from −4 to +76, with one outlier at +283.
(Methodology/source: https://news.ycombinator.com/item?id=32547760.)
(Methodology/source: https://news.ycombinator.com/item?id=32547760.)
Funnily a comment I posted yesterday just passed the 75 points, so it appears that either there is no cap or that it was lifted.