I've done something to my bolt.

[The Gun Pimp]

If you store you bolt separate from your rifle, it's a good idea to de-cock the bolt to save the spring-tension - especially if you go for weeks without using it.

Can't believe I'm going to contradict Vince.....

A spring held under tension under normal circumstances will suffer no ill effects at all. It is fatigue, through the work of compression and expansion that weakens springs. Being held under load can be effected by creep deformation, but only when held under load and temperatures are high enough to deform the spring material to the compressed dimension.

I'm not going to argue that point but firing-pin springs do get shorter over time. I've just received some new Stolle Panda springs and they were about a quarter-inch longer than the one in my rifle. And I always de-cock it at that!

[Ovenpaa]

I seem to remember something about coil springs losing most energy in the first 24 hours after manufacture than for the rest of life when left uncompressed, however I have never actually confirm this. I tend to de-cock some such as my Barnard and Accuracy International and the latter seems easier to de-cock than it did 10 years ago.