Does an AEG's spring compress / weaken over time? (and Guarder springs)

Fatboy40

Fatboy40

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I'm assuming that a stock / potentially lower quality AEG spring will over time compress slightly, ultimately reducing the AEG's power / FPS, would others agree that this assumption is correct? The reason I ask is that my DE M904E is getting approx 10 to 15 FPS less now on chrono, on 0.25's, than when I first got it a few months ago.

I'm going to get a Guarder SP100 from AK2M4, which will possibly take me a little over the 350 FPS / 0.20 limit. If this is the case I'm also assuming that being a better quality spring if I compress it for a while, not too much, it will settle to a more permanent strength?

 
There is a small amount of creep in these springs. The spring in my scar settled and that was three years ago.  The FPS has always been consistent. I think things would get worse if you had not used an AEG for many years, someone on these forums should know and give you a better answer.

 
Its just as likely that the chrono was inaccurate.

Went to a site where they had two chrono's which read 50 fps different ?

I had an AEG which was slightly hot and left it half cocked (spring compressed) to see if I could get it down by 10-15fps.

I tested every couple of weeks and it did eventually work but had to keep it like that for about six weeks.

Its true that a low quality spring may deform more quickly.

 
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EDcase said:
Its just as likely that the chrono was inaccurate.
Click to expand...
Click to shrink...


I almost never consider the potentially obvious things, so I just got out my own chrono for a few tests.

I got the same FPS on 0.25g as I did yesterday, around 290, and 0.20g are down by 20 FPS from the first tests I did against the gun (0.966 J). I've no reason to doubt the ML bucking / air seal so I'll get the SP100 first and see what the results are.

 
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I'm no expert but have a small bit of experience with spring making companies as I have my own (Gearparts) springs made. 

Yes stock springs on the whole will lose power over time.  They're generally made from cheaper non-tempered wire, sometimes call "piano wire".  This wire is readily available and cheap.

My own springs are made from oil-tempered Japanese SWOC-V steel and less susceptible to shrinking overtime.  The M110 I've been testing for the past 18 month 300,000 cycles is still the same length as day 1.  I've never performed a stress test on Guarder but imagine they are pretty much up there.  

 
@Fatboy40 haha, you should be fine with the sp100, I get around 360fps with 0.2g (sorry I don't know the J).  As an interesting experiment the start length is 170mm, let me know what the length is after a couple of 1000 BB's

 
So if I buy one of your springs with the Japanese steel, will that make my BBs sharper?

Hattori Hanzo style ?

 
My Guarder SP100 spring, and a few bits to tweak my sons G&G Firehawk, arrived today so I cracked on and replaced the spring in my Double Eagle M904E (so easy to do with a quick change spring / V2 gearbox).

The stock spring when removed was 160mm in length and had no tighter coils at either end, and as stated earlier the Guarder SP100 was 170mm, and the SP100 was fitted with the tighter coils on the spring guide. On 0.20g I went up to approx. 342 FPS and 1.09J, and on 0.25g it was approx. 306 FPS and 1.09J.

So, at the moment, I'm a happy bunny but a bit miffed that at my game on Sunday I was shooting 0.25g's at around 16 FPS lower than I could have been and was when I first got the AEG.

I'll report back towards the end of December for @ak2m4 and list the FPS (but will only take the spring out if the FPS has noticeably dropped).

 
@Fatboy40 Don't be too miffed about the drop in your DE M904E, it's actually firing a little low but it's good enough without having to open it up again.  The stock spring could be fine, problem could even be with the cylinder head, piston oring, nozzle, bucking, hop chamber etc.

 
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