Complex sentence: To this end, master gunners first simply used larger powder loads, which, however, exerted larger pressure on the existing cannon and could make the cannon burst, causing the death of the irreplacable gunner with his crew (and even kings).
Split into simpler sentences: To this end, master gunners first simply used larger powder loads. These, however, exerted larger pressure on the existing cannon and could make it burst, causing the death of the irreplacable gunner with his crew (and even kings).