Complex sentence: It was too severe, and I seldom fired it, but it is a curious fact that I never shot a fire with that rifle without bagging, the entire practice, during several years, was confined to about twenty shots.
Split into simpler sentences: It was too severe, and I seldom fired it, but it is a curious fact that I never shot a fire with that rifle without bagging. The entire practice, during several years, was confined to about twenty shots.