They can. They are more precise because of the way they shoot. You don't need to worry about rubber. A pneumatic speargun's power will determine how difficult it is to load. To make your life easier, look for loaders that are included in any purchase. Pneumatic spearguns are precision-engineered, but as a result, they can often be rendered useless by dirt or grit. They are difficult to maintain because the firing mechanism is completely enclosed. A banded spearfishing weapon is the best option.