I was sighting in with my buddy the other day and his first shot did not fire. The primer had the smallest dimple. I know the primer was seated properly as I 'felt'it before I handed it to him. The second and all subsequent shots fired. I am sure that he put the gun(Rem 7600) away last year with the hammer 'cocked'as he has done for the last 15 years. I suspect that a combination of a weak spring on the hammer and poor lubrication was the culprit. My question is, do any of you know if storing a gun long term in 'cocked' position weakens the spring?

I always lower the bolt with my finger on the trigger to store my rifles with the firing pin spring relaxed, but this is just my anal-retentive habit and has more to do with my imagination that the sear contact points are somehow in a strain all that time. I don't think that not doing so will weaken the spring appreciably.

It is more likely that your friend's firing failure was a combination of sticky parts and (as is famous in actions like the 7600), generous headspace that allowed the cartridge to be positioned forward in the chamber and minimize the firing pin strike.

Most of the newer guns have fine springs. I think they may take a "set" if stored cocked for too long, but not weaken (your friends rifle fired every round after the 1st).