Re-seal FAS 604?

[Monco]

I have a FAS 604. I appreciate this is a low velocity gun to start with, but recently I have formed the impression that the velocity is getting lower, based on, e.g., poor penetration of targets at 10 metres and the feel of the cocking effort.

I’m thinking the gun needs the seals replaced. Is this likely to be justified?

There appears to be no factory support for this model any longer, but I see seal kits advertised by vendors in the UK. Are these kits likely to be of decent quality?

Likewise I see on the web details of how to replace the seals yourself; in the real world how easy is this job to do for someone with very basic mechanical skills?

Alternatively, would anyone recommend a smith to do the job?

[PhatMan]

Monco,

This video (annoyingly age gated) shows the whole reseal process :

https://www.youtube.com/watch?v=TlGQbR0iUAU

Have fun

Best regards

Russ