S&W 77a seals

[thescrawler]

So, I have this S&W 77a that is a heck of a shooter. Ive done alot of work on the trigger and rebuilt the flat head piston. The problem that I have is the air chamber seal cups were worn out. I have ground out and rebuilt them with 5 different epoxys over the years trying to find one with the right hardness level to hang in there for the long haul, but to nonavail. Every time I do it, it works great for a little while and then stops working again.

I am hoping the combined minds on here will have some suggestions for me.

Thanks in advance.

 

[Skillet]

Mac-1 rebuilt mine. U need only send the piston assy, not the entire gun. It uses the same piston seal as a CR 1400.

Read that a former Crosman engineer 
went to S&W and helped develop their air gun line. Mine likes superdomes. A 14-15 fp rifle. For years I used only 10 pumps, 'till I read an owner's manual and discovered it's designed for 20.

"Cracks" pretty good, @ 20 pumps