My gamo whisper classic with the nitro piston is recoiling hard and is deforming the opening on the scope stop. I just ordered the plastic bumper stop that Gamo makes but is this normal?

Most serious scope owners know that cost is no reason to get a scope. The cost sometime exceeds the value of what it is on. Cheap scopes are not worth the effort to work on.

Gamo Big Cat 1250 Problems - Airguns & Guns Forum

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Feb 24, 2013 - 20 posts - ‎8 authors
Gamo Big Cat 1250 Problems, Air guns, Airgun Forum. ... OK, so I bought my first air rifle since being a kid with a crosman 760 and it was a .... but when you get into the 800 and 900 fps range they tend to lose accuracy fast.

gamo lost power Questions & Answers - Fixya

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Get free help, tips & support from top experts on gamo lost power related issues. ...My gamo whisper classic with the nitro piston is recoiling hard and is ... IM LOOKING FOR A REPLACEMENT MAINSPRING FOR GAMO BIG CAT 1250.

Big Cat® 1200 Air Rifle ' Gamo USA

The three reasons that stop a springer cocking are
1 main spring has broken and stopping the piston reaching the trigger sear and engaging . remove spring to check
2 trigger is jammed and not allowing engagement of sear or trigger unit is broken (may be a spring broken easy fix )
3 piston engagement slot damaged broken ( replace piston)

If it is trigger wear problems think about getting it repaired or replaced depending on length of time owned

http://www.airrifleshop.co.uk/Airgun%20manuals.htm
Has some gamo manuals not the specific one you want but has all the important info for safety and operation plus zeroing if its a parts diagram you want look at the following link
http://www.aceros-de-hispania.com/MANUALES-DESPIECES/DESPIECES-CARABINAS-GAMO/despiece-silent-stalker.jpg

I have a similar Gamo air gun and the serial number is on the barrel on a flat spot on the side near the hinge.

Yes if you meet the FAC inspection standards and pass the interview

I'm not familiar with the scope, is it an air rifle scope? One stroke type? If not, the backwards recoil of the air rifle is tough on a normal scope, they aren't made for that type of abuse. They work fine with a normal recoil. That is why they started making air rifle scopes. I'm sure that the internals of your scope are damaged somewhat, you can take off the eyepiece no problem, you might find something in there, loose screw, missing screw, you never know, don't get too carried away with the dis-assembly, you'll never get it back together. It sounds like the magnification ring is messing with the focus of the eyepiece. Might just need some oil. Hope this helps.

You either have a piston stop bumper failure or some damaged orings. Look on the schematic and the piston stop bumper is number 11, part #107236. A lot of times the piston stop bumper will disintergrate due to becoming brittle from the compressed air and not having enough lubrication. Look for small plastic balls in the head under the valve. If you see little plastic pieces than that is what remains of the piston stop bumper. You will need to remove the valve from the head cap in order to inspect the bumper. Also inspect all orings. The slightest damage can have big effects. One other thing to look for is damage to the plastic valve that rides on 3 orings. (2 out and 1 in) I don't believe you have valve damage because you say it is firing like a machine gun. This is almost always the piston stop bumper.