GAMO AF-10 won't cock

[jan1973]

Hi everyone,

This is my first post here on GTA. I have a GAMO AF-10 and it won't cock anymore. I'm a beginner when it comes to repairing air rifles/pistols so I hope you'll bear with me. When I took it apart I noticed the sear spring was longer than it should be and I replaced it with a new one. I was able to take a few shots and then again it wouldn't cock. The top closed without any resistance which shouldn't happen ofcourse. Again, I took it apart and I took the valve from the valve block. The O-ring didn't look perfect, but it was still there. After some begging I was able to borrow a valve from someone else and I put it in the AF-10. I thought I had fixed the pistol as I was able to shoot again. It took a few shots and then it showed the same behaviour : it won't cock and the lid closes very easily so it's not compressing air in the piston.  Can anyone  tell me what's broken in my AF-10? Oviously, the sear spring and the valve aren't the issue.

[Back_Roads]

 It is very much like the Beeman P-17 pistol, do a search on that here or Google, much modding has been done to these. I think it may be the internal valve lever that has become bent and needs re alignment, this happens from trying to recock the gun, other thought is the weaker spring, has taken a set, try the OE spring again

[jan1973]

Thanks for your reply. I've looked at an exploded view diagram of the beeman p17 and internally it seems to be different. The piston might the same but the valve system is different. Maybe the beeman p17 is more like a gamo compact or gamo pr45? Your reply did make me think though. The spring was extended to an abnormal length, the only part that could be bent to cause this is the sear. I'll have a look if I can take it out, I will have to remove the valve housing from the cilinder get a good look. The part that I can see looks ok though.

What do you mean with internal valve lever? The AF-10 has a valve that's inside the valve housing, as far as I can tell there's is no lever, just the sear that holds the valve up.

One thing I forgot to mention in my original post: when the pistol malfunctions after having able to fire several shots the valve seems to have gone down beyond the point where the sear holds it back while cocking. So if you try to cock it then, the valve just doesn't work and all of the air is just blown out of the cilinder instead of being compressed in it. I have no idea why the valve goes down so far.

[Back_Roads]

 Yes I meant to say sear, I guess it is the best description.