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old joe krantz · Member

Say I like to sit on my back patio reading with a pipe and a cup of tea. And if the sun is out, gophers will periodically pop their heads up for a few seconds here and there. (3 and counting!) Is it detrimental to the airgun to leave the spring cocked for short periods, say 10 minutes, half an hour, an hour? Is any damage to the gun likely to happen all at once, like a spring failure, or would it mostly be a gradual decline in performance or is it completely harmless?

The window of time to get a shot off is usually very small and the motion and sound of cocking clearly alerts them. Thanks.

walter · Veteran Member

i have heard its not a good idea. i dont know the amount of time at which this happens but im sure someone will be along to help. i would guess the longer the set in cocked position the more chance of losing power to a spring that will not fulling come back to extended lenght. be careful.

Alstone · Moderator & Site Supporter

One of the Airgun magazines over here ( England ) did a test on a range of springers, to see if prolonged spring compression affected performance.

Webley came out top after being compressed for two weeks the performance was down 5%, and most of the others were not far behind. Apart from some of the cheaper models which didn’t come out very well at all.

The conclusion was that prolonged compression made no difference to the working of the spring, apart from a decrease in performance, and when this got too low then change the spring, but this would take many, many hours of compression before you needed to do this.

AL

Dukemeister · Member

Up to 30 minutes cocked would seem to have negligible effect, but more testing is needed. Someone needs to take up the cause where Cardew et al left off. Anyhow, an old thread on the Yellow that I saved gives some results:
http://www.network54.com/Forum/79537/message/1219232516/How+Long+Can+I+Leave+My+Spring+Rifle+Cocked-
The tests were done on .177 calibre rifles using one type of pellet. The results show that after a week left cocked the average loss in velocity was a mere 2%. The overall trend is plotted here:

Of course, there are no data for repeated cycles of 30 min (or any duration), so it is unknown from these tests if the velocity loss is cumulative with repeated cycles or if the springs "recover" after resting.

old joe krantz · Member

Well it does seem to have an effect.

rsterne · Moderator

A whole week of being cocked costs 1-3%.... I wouldn't worry about it.... I often wander around when hunting for several hours with the gun cocked....

Bob

Alstone · Moderator & Site Supporter

The main thing I find is spring recovery time, I tend to go Pigeon or rat shooting for up to four hours at a time, and between shots the gun is permanently cocked. When my TX200 was new there was a drop in fps of around 30fps over a few hours, but over time it has got to around 10fps which it recovers next time I go shooting. I re-shimmed the spring to the fps I wanted and things seem to have stabilised now.

It does seem to depend on how much spare capacity there is in the spring, if your binding the coils I would have though the damage would be greater than a spring running a bit slacker?

A while ago Webley brought out a new spring which suffered no fall off in performance from being compressed for long periods, this was tested by "Airgun magazine" and found the claim to be 99% true. I'll see if I can find the article and post it.

Al

Crosman140 · Senior Member

As others have mentioned, these guns get taken out in the field all the time. They are cocked, locked and ready to rock.

Enjoy your time out on the porch with your springer all ready to shoot so that the next time those little buggers pop their heads up, your ready to let 'em know whose in charge.

walter · Veteran Member

im very happy to hear its minimal if anything. makes me feel better about using my gun cocked for a bit. thanks every one. walt. Mr. Green

cheez · Member

cactusrat · Member

The way I see it is that the spring will break way before it looses enough power to worry about. Keep them cocked while hunting. Buy a new one when they brake. I’m talking cheaper guns here.

On high end guns they are worth sending off to have them fix or if you can diy.

Springs breaking is one of the things that pushed me into the Dark Side. Now that I’m here that is no escape. HELP ME!!!!!! Boozing It

720fly · Veteran Member

How about a nitro piston to replace the spring? I don't know if your gun is compatible or not. It could be worth it?

old joe krantz · Member

cheez · Member

I have thought about this since the topic first came up. If leaving a gun cocked for a few hours effected the spring in a permanent negative way then it is doubtful to me that anyone would be able to sell these guns. Think about it. Say you pay $400-$900 for a quality springer to hunt with. If everytime you hunted you lost a few percentage points of FPS it would not be long before your gun would be useless. Or by the same token if a couple times a year you had to replace the spring it would be too expensive for the vast majority of people to afford. JMHO but common sense would tell me the Germans and Englishmen produce a better product than some might think.

Dukemeister · Member

Grad students are on the right track. The actual mechanism involved is not creep (because the temperature is too low), rather it is relaxation. The fatigue life of a spring will not be affected by the length of time cocked, only the number of times cocked and the severity of the firing cycle. The surface condition of the spring is also critical to its fatigue life. Any nicks or scratches will lead to a short life. A highly smooth and polished surface will give the maximum life. Anyhow, stress relaxation is what causes the spring to lose power when left cocked for extended periods. A brief overview is given here:http://www.rockfordspring.com/relaxationofsprings.asp