Thanks Kwokwai, I've found a place to buy replacement springs, 4.99 before shipping. But I don't see replacement o-rings on any site that sells gbb parts. I guess they assume you can go out and get them locally.
Does anyone know what size it is supposed to be or how I can figure out what size it should be?
It's part 28 and is listed as Main Piston Seal which isn't very helpful.