In answer to the original question about the Taurus semi-auto:
I doubt that leaving a hammer spring cocked will degrade it much. In fact, for most DA/SA guns, firing the gun in DA mode compresses the hammer spring farther than when the spring is locked back in SA mode for fired in SA mode. I wouldn't worry about it. You don't hear of hammer springs failing much...
The following is a rehash of things discussed here on a regular basis, but it continues to come up.
Bill DeShivs said:
Wear on any spring in the gun is negligible, so it doesn't matter if you leave it cocked, uncocked, chamber empty, slide locked back, whatever.
It depends on the gun and it's design.
Were the original poster to leave the slide of his Taurus locked back for an extended period, he might find that the recoil spring has lost a lot of its strength. (A few years ago a participant on this forum told about that happening in his Army NG unit's armory; the NCOIC had to get new recoil springs for nearly all of unit's M9s (a gun that is very similar to the Taurus being discussed) after he had stored them all that way the prior winter.
On the FN Forum shooters who install red-dot optical systems with silencers or compensators on their FNX-45 Tactical semi-autos have found that when the new equipment is installed, the guns suddenly seem to be OVERSPRUNG. They won't cycle! The extra weight of new optical sighting systems and the muffled or redirected gases from silencers or compensators change how the slide and barrel behave.
They also find that there are no lighter recoil spring assemblies available for those guns from the gun maker or in the after-market. Rather than building replacement recoil spring assemblies (using aftermarket prings and guide rods designed for Glocks [which have very siimilar guide rod assembies] most of the shooters have found they can weaken the existing recoil springs by leaving the slides locked back for a week or two (or three). The guns then cycle properly. Most of us don't leave slides locked open, but it can be done and it can be done out of ignorance.
As you well know from other the many discussions about this topic we've had on this forum, some gun designers INTENTIONALLY over-stress certain springs. Why? Because that may be the only way to make a very small gun function as intended. To do that they have to use less metal and push that smaller metal spring harder.
The point, however, is that springs can wear out from more than just cycling alone.
The same is likely true with some HIGH CAPACITY MAGAZINES, but not all of them. Wolff Springs routinely recommends downloading all hi-cap magazines a round or two if they are to be stored for long periods. This is on the FAQ page! (Wolff doesn't sell more mags when they tell you how to prolong spring life.)
Small recoil springs? Let's talk about the Rohrbaugh R9, which is arguably the smallest 9mm semi-auto available. Leave that slide locked back for a couple of weeks and tell us how well that gun works at its next range session. The R9 recoil spring has a recommended service life of 250 shots -- which is roughly equivalent to running 40 mags through the gun. Rohrbaugh traded off long recoil spring life so that he could build a smaller gun that worked well -- as long as you keep the easily-changed (and relatively inexpensive) recoil springs fresh. I wonder why a R9 spring should only lasts 250 rounds, while some other gun springs may run for thousands of rounds. Cycling alone doesn't necessarily kill springs, but how a spring is used -- even if it's used as intended -- can do it in.
JoeSixpack said:
But I will say that it does not matter how you store it as far as the springs are concerned, research has shown they wear out due to compression/decompression cycles.
Can you cite that research for us? Otherwise your claim is the firearms equivalent of fake news: it sounds right, but there's nothing to back it up. If you
can offer research that shows that cycling (and not deep compression) kills springs, you'll have added to our base of knowledge and earned our appreciation.
A number of engineers who participate here, (including a Metallurgist or two) have told us that the long, deep compression of a spring (which
can happen when a gun is cycled) is where the damage and wear CAN occur. And if you leave the spring DEEPLY COMPRESSED, the longer it stays that way the greater is the likelihood of damage. But only if the compression pushes the spring to or past the spring's design (elastic) limits.
If you have a full-size 17-round mag and never load it past 10 rounds, that mag spring may outlast both the gun and the shooter, regardless of how many times it is cycled. The spring just won't be pushed anywhere near its design limit. But if that mag is left loaded with 17 rounds for a year or two, you might see a dramatic reduction in spring strength - and in a few cases, the may won't even allow the gun function when used.
It all depends on the spring's design and how the spring is used.
JohnKSa, a
Firing Line staff member and also an engineer, has conducted his own research. I think he would disagree with your claim about cycling. Here's a link to some of his work posted on this forum, and his related comments:
https://thefiringline.com/forums/showthread.php?p=6005156#post6005156
JohnKSa also knows a bit about spring powered air guns, and he has posted links to studies done by experts familiar with those types of springs.
Cycling isn't necessarily a spring killer. Most tappet springs in motor engines will cycle many, many millions of times over their life and never fail -- but they were designed so that they can't be over compressed. Most gun springs are like that, too, but there are exceptions -- cited above.
Most sure is a Sixpack hasn't spring Tension to worry about, isn't it?
I did today an gruesome range session of a whooping 4 rounds.