The insides of a double rifle's action have been compared by some with the insides of the human body. Generally, if all is well and working as it should, it is better to leave well alone and carry on. When things go wrong, however, they often go wrong badly and this is when the services of a “surgeon” in the form of a highly skilled gunmaker is called for.
Although over the years a handful of action designs were introduced that made use of coil springs, the British by and large favored the use of leaf springs instead. Leaf springs are, however, tricky to make and require not only careful filing and fitting but a touch of metallurgy as well to work properly. I know of very few instances where leaf springs, even some very old ones, have failed, but being mechanical in nature they certainly can fail. Since it is impossible to predict exactly when a leaf spring, especially an old one, will fail, this is one of the risks inherent in old British guns and rifles that must be accepted beforehand. The same goes for other parts of the action such as the hammers, firing pins, cocking levers, and the like.
In my time, I have had exactly one leaf spring break on me. This happened on the first morning of a high-end guinea fowl shoot in
