Complex sentence: On December 24 Kordecki refused to surrender once again, and the Swedes went back to shelling the northern side; during one of their most heavy barrages the second of their 24-pounders malfuncioned and was destroyed.
Split into simpler sentences: On December 24 Kordecki refused to surrender once again, and the Swedes went back to shelling the northern side. During one of their most heavy barrages the second of their 24-pounders malfuncioned and was destroyed.