nglitz wrote:"Springs are damaged by repeat stress fatigue, working them beyond their range, or ultra high temperatures taking out the temper. Not time."
The most accurate description of spring wear outside of metallurgical textbooks. Any spring that is damaged by being left normally compressed has very poor spring design or metallurgy.
Not time.
Thanks for supporting my view .
I think the OP's rifle is needing some TLC
So...
I changed the firing pin spring(have run more than 1000 pellets),I changed the air cylinder,I treat the rifle with a lot of looove,but today I felt like I wanted to throw it in the target range...
As I was practicing,at about the 50th pellet,it lost velocity...
POI was at 8,six o' clock...
Unscrewed and screwed the cylinder back and everything was normal...
At about 70th pellet,the same thing again...except that unscrewing-screwing didn't fix the problem...(air cylinder volume was a bit below 125 bars,don't know if that matters and I didn't have time to fill it up and shoot again)
What could the problem be?
Well,we don't have a qualified FWB dealer/service here so I guess I must pack and send it to mother FWB...
Strange thing is that with a cylinder charged at 175 bars,I don't face that behaviour...
assuming you have access to another p70 (that works well) you could try and change one item at a time to see where the failure is.
suspects are
1) all the springs in the air path (not just the velocity spring)
2) all the orings (the exploded diagram has the necessary sizes in order to obtain them locally)
3) the valve and its seal
4) the regulator
5) the cylinder
