Disadvantages
The break open design is best suited for non-repeating firearms. To get multiple shots requires either multiple barrels or a revolver cylinder; while this is fairly simple for shotguns, with double-barreled shotguns quite common and even four-shot designs like the FAMARS Rombo available, double rifles require very precise alignment of the barrels so they shoot to the same point of aim. Modern double rifles are very expensive, and designed for short range use; the barrels are often regulated for ranges under 100 yards (91 m) for use against dangerous game.
Wear in the mechanism is focused upon the small contact area of the latch, and the breech is difficult to seal properly once the latch wears. In some firearms, such as the Thompson Center guns, the latch is a removable part that could be replaced when worn. Designs without a replaceable latch may be fixed by building up the worn part with a welder, then filing back to shape.
Break-open actions are also not as inherently strong as other action types, rendering it capable of withstanding only relatively low pressures. The action is usually held closed by a single locking lug, usually below the barrel in a single shot or between the barrels of a double barreled gun. The single lug must carry all of the force of firing the cartridge. For shotguns, which operate at very low pressures, this is not an issue.
Some centerfire rifle cartridges, however, can generate pressures that may be too great for a single locking lug, if it is not stout enough. The Thompson Center Contender, for example, was limited to .30-30 Winchester level cartridges. To fire more powerful cartridges requires a much larger locking lug, such as that which Thomson Center used on the larger Encore model. By comparison, while bolt-action shotguns may only use a single locking lug, almost all bolt-action rifles use multiple locking lugs around the perimeter of the bolt to provide an even distribution of the forces of firing, giving a much higher intrinsic strength. Since many break open rifles, such as the inexpensive H&R models, are built on large frames originally meant for shotguns, the action is very heavily built and capable of handling moderate to high pressures. Still, belted magnum cartridges such as .300 Winchester Magnum are generally only found in the highest quality, very expensive break action rifles.
Break open designs work best with rimmed cartridges, which can use a solid extractor. Rimless cartridges require a spring-loaded extractor, which can slide out of the way for cartridge insertion, and spring back to engage the recessed rim. While these spring-loaded extractors are found on even inexpensive models, the spring-loaded extractor is not as strong as a solid extractor, and increases the likelihood that failures to extract will occur.
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