Air Arms S200, sudden loss of power question.

[Geoff555]

Hi all, This S200 (.22) is fitted with a Huma external regulator and has me puzzled, the pellet probe and cylinder seals have been replaced as they are a 5 minute job and no trouble.
What happened is this, running at 11.3 ft-lbs and suddenly noticed ,literally one shot to the next, that the sound had altered and sounded 'soft.' checked and it had dropped to 9.2 ft-lbs and varying. Winding the hammer spring up makes no difference, tried new spring, same.
Any suggestions would be very welcome.
Many thanks.
Cheers.
Geoff.

[Rich]

Could be muck on the striker pin, the one with the JC circlip. Or bent pin.

[Geoff555]

Hi Rich thank you, I did check the pin when I replaced the cylinder/block seal, straight, clean and free.
Cheers.
Geoff.

[spartan]

The regs probably failed.

[Geoff555]

Hi, the mystery deepens a lot, I did consider a failed regulator so I took a complete cylinder and reg. off a fully functional S200 which was a known quantity.
The result was 8 ft-lbs. So that leaves a faulty breach block, internal crack?? and a barrel problem?? The answer is that I don't know, just on the off chance it was low batteries in the chrono put in new ones, OK I was getting desperate and reaching for an answer.
As I am going round in circles, scratching my head and that hurts, I am going to leave it for a day.
Thanks all.
Cheers.
Geoff.

[Rich]

Most unlikely to be a cracked block, it's aluminium and not a very hard grade at that.

Oil on the hammer? Transfer port adjuster screw problem? Probe O ring blown off? Broken hammer spring?

If the problem persists with a different cylinder you can rule out the reg and the firing valve.