Hw 97 losing power

[SlowTurtle]

Initially I thought it was just the colder temperatures but after a few warmer days the gun is till shooting 3 to 4 mils lower and inconsistently at 55 yds. I guessing that I've probably put 15000-20000 pellets through it since it was tuned.

I've had broken springs before and it doesn't really feel like that but it's hard to tell without busting it open which I'd rather not do unless necessary. 

Any advice or ideas would be helpful. Thanks.

 

[Bob-in-WV]

I would change out the breach seal first and if that doesn't help, it may be time for a rebuild.

 

[hitech]

Have you chrono'd it to see if it's actually losing power? Like Bob said, the breech seals is where I'd start. The sliding chamber in the 97/77 make it more difficult to replace but it's still not hard to do, and it's cheap. If the rifle was previously tuned, it also may be a piston seal that is worn or just needs a refresh of lube. Springers are generally easy to work and cheap to replace parts.

 

[SlowTurtle]

I would change out the breach seal first and if that doesn't help, it may be time for a rebuild.

Have you chrono'd it to see if it's actually losing power? Like Bob said, the breech seals is where I'd start. The sliding chamber in the 97/77 make it more difficult to replace but it's still not hard to do, and it's cheap. If the rifle was previously tuned, it also may be a piston seal that is worn or just needs a refresh of lube. Springers are generally easy to work and cheap to replace parts.

I went ahead and ordered both seals. I'll try the breech seal first and see where she goes from there. 

I didn't want to crack her open because she was shooting so well and I'm a shooter not a tuner and didn't want to bugger up a fine tune job.

I don't have a crony but it's looking like I might be in the market for one.

Thanks for the input.