Dry Fired by Accident

But it can...

You should be very careful to never dry fire a spring air rifle. I had an R10 that broke a spring upon dry firing the first time. I had it Diana model 48 that broke a spring after a number of dry fires I'm not sure how many. I had a 460 that I lent out. It came back with a broken spring. I don't believe that it had been dieseled.

If the rifle is still shooting to point of aim, it is unlikely that you did any damage unless point of aim changes drastically in the next few dozen shots.
 
I've had a single dry fire ruin only one gun of mine, and it was a xisico. Mike melok even knew I dry fired it, and replaced it at NO CHARGE for me (it was one he tuned for me. He disassembled it to determine what went awry, and said the only problem he noted were the forks had loosened up. He used the gun for parts and tuned another for me). The gun went from being a laser to opening up to soda can accuracy and the ES's went from single digits to double digits.... Don't know why he did that, but it was tremendous in my eyes. The gun was shooting perfectly until I dry fired it by accident...thought I had loaded a pellet, and knew I didn't with the crack it made and lack of any hole in the target...

If the gun is shooting as before, I wouldn't worry...


 
Gamo is fine to dry-fire. They even say so. One of the few break-barrels I've seen that do.

As someone else here who asked the same here quoted:

”Repeated test-firing – before launching any new rifle to the market, Gamo tests them by dry firing each rifle model 100,000 times (10 units are shot 10,000 times each). Once the product is launched, two out of every 1,000 are tested again with 10,000 dry fire shots. In addition, ALL of our air rifles are checked part-by-part, and each is shot and tested by a robot to ensure the power, grouping and velocity required by our exhaustive quality control standards..."
 
I wouldn't get into a habit of accepting that dry firing a spring piston gun is ok. You might forget its loaded. Same as I wouldn't make a habit of dry firing a firearm. Its bad habits that develop and thats where the accidents happen. 

A SPRING piston gun isn't meant to be dry fired. A gas ram might be OK? 

Although, when I was a kid, I dry fired my old Diana 24 a zillion times. It was left cocked for months once. It still has the original spring and internals look like new. Has thousands of rounds through it. Shoots around 590fps and a SD of 3. So, this one survived.