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#618536 08/23/22 11:17 AM
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Nitrah Offline OP
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An engineer friend and I were discussing using snap caps in our doubles to relax the main springs when not in use. His view is to Not use snap caps and relax the springs as it is just one more cycle. He feels leaving them compressed does not shorten their life but the actual use, compressing and firing the gun is what wears them out. Is there a right answer?


This ain't a dress rehearsal
Nitrah #618540 08/23/22 12:32 PM
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There are x number of cycles in any spring. "Relaxing"The spring uses up a cycle. Think about bending a wire back and forth until it breaks is an example. The wire isn't heat treated so it has fewer cycles until it breaks. If the maker of the spring gets the heat treat right and removes stress risers by proper polishing the spring wil have more cycles built in. But they all have a finite number of cycles.

Nitrah #618541 08/23/22 01:02 PM
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Originally Posted by Nitrah
An engineer friend and I were discussing using snap caps in our doubles to relax the main springs when not in use. His view is to Not use snap caps and relax the springs as it is just one more cycle. He feels leaving them compressed does not shorten their life but the actual use, compressing and firing the gun is what wears them out. Is there a right answer?

Your engineer friend is correct.

1 member likes this: Tom Findrick
Nitrah #618542 08/23/22 01:29 PM
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Hunter Arms would agree also; the back of post-1920s hand tag
"We advise leaving the gun cocked at all times."

[Linked Image from photos.smugmug.com]

Nitrah #618573 08/24/22 04:21 AM
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Despite the general consensus here, I will continue to store my guns with their mainsprings in an uncompressed state.

It is well known that springs under compression lose strength over extended periods of time. Gun magazine springs become weaker when left fully loaded, and may begin to cause feeding problems. Leaf and coil springs in vehicle suspensions definitely begin to sag over time. Valve springs in engines stored for long periods will show a measureable difference in uncompressed height, and the eventual loss of strength can lead to valve "float" at high rpms.

https://idcspring.com/spring-lose-tension-when-compressed/

None of my guns is likely to have spring failure because I have fired them the tens of thousands of times required to exceed the maximum average number of compression/extension cycles before failure. For almost all of us, the greatest threat to our springs is incorrect polishing and tempering during manufacture (generally beyond our control), and stress risers that occur due to corrosion. In other words, a rusty spring is more likely to break than a spring with a clean polished surface. I'm pretty sure that a real metallurgist who knows a bit about springs and heat treatment would agree.


A true sign of mental illness is any gun owner who would vote for an Anti-Gunner like Joe Biden.

Nitrah #618629 08/25/22 11:53 AM
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By a metallurgical engineer from one of the frequent thread on Trapshooter.com

All ferrous metals, like springs, will "take a set" over time, and all ferrous metals. like springs, wear due to being "cycled."
However, the "take a set" takes lots of time, many years, and is enhanced if the metal is at high temperature (which gun springs, generally are not.)
So, you have to ask yourself, is it more damaging to the spring to "cycle it" one more time to de-tension it (and remember, it is STILL under tension even if you let the hammer down) or is it more damaging to leave it under tension.
For gun springs, especially if you replace them periodically like you should, I am pretty sure the answer is, it doesn't make a darn bit of difference.

On the same thread it was stated that both Beretta and Perazzi, and made in USA Kolar, recommend using snap caps.

Another engineer on the same thread
As an engineer I look at the Perazzi spring and question the extremely small radius at the corner. The stress concentration must be very high near the corner. I also wonder how the pin is attached. I think that it is welded which can do interesting things locally to the spring metal. Sometimes that local heat can help relieve manufacturing stress, sometimes it can really screw things up. Again, without knowing what manufacturing processes are used, I would just think that increasing that bend radius would greatly expand the useful life of the spring. Marcello Guliani's version of the spring must have a longer working life because of the way he rounded that corner. Once I run out of factory Perazzi springs I will switch brands.
What we do know is that it is very easy to either drop the hammers on a snap cap or a penny, or pull the trigger assy out and drop the hammers manually. Why would you even risk shortening the spring life by leaving them cocked?
For those with coil springs, they don't seem to be as sensitive to breakage, but again, why shorten the life of the spring when you can drop the hammers so easily?

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I currently have 3 12 gauge L.C. Smiths- which I shoot rather often- I use snap caps in them, to relax tension on the V-springs, and as far as the ejectors are concerned, having coil springs, those springs are under tension until the gun opened, then they "relax" when they act on the ejectors hammers to expel the snap cap, or fired shell casing. But I do not use them in my older (1940 era) 12 gauge M21--never had an issue with broken springs either. RWTF


"The field is the touchstone of the man"..
Nitrah #618632 08/25/22 12:14 PM
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c. 1900 Parker hang tags
"We recommend snapping hammers down (BTW without a snap cap) when put away for great length of time. (It takes tension off the springs.)"

Nitrah #618633 08/25/22 12:19 PM
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Is there any truth in the theory that dropping the hammer without a snap cap produces avoidable stresses on the nose of the firing pin?

Nitrah #618634 08/25/22 12:19 PM
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As an engineer myself, I agree with your engineer friend. As a restorer of double guns and maker of springs, I can add this. I see many guns that have been sitting unused
and left cocked for decades. When I remove the parts, clean and then reassemble, the springs are just as good as when they were made over 100 years ago in most cases.
Also consider this, most people at the turn of the century didn't use their guns any where near as often as we do today, with clay shooting and all, I would wager most were all kept in the
cocked position, when put away.

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