The captain hits the dwarfs M helmet with L weapon, plus sharpness star, and over strength chit the article states this as a heavy hit destroying the helmet.
If this was an article about 1st edition basic combat, then it would be correct. In the 1st edition rules, losing a sharpness star when striking armor was only an optional rule (2.3 Armor Bonus) that probably wouldn't used by beginners.
If you could identify the exact article that you are reading I could check it out myself to be sure.
I thought this would be a medium hit. L + sharpness + over strength = H. Then subtract sharpness for M.
Yes, this would be correct for 2nd & 3rd edition rules.