I have a 500x.And I want to see if the 1000x springs will fit?Any one have the spring length of the 1000x also the lenght of the chamber as well? I have a Hatson 55 spring and its to long.total lenght is 11 1/4, My 500x spring is 7 7/8. Tks Mark

Actually, the modern hatsan 55 spring should be the same as that of 1000x, as these two rifles differ in stock only and little minor design differences, probably also a tophat present in 1000x. Length of the modern 1000x spring is 13-14", uncompressed, new (there was also a shorter version similar to yours, with a heavier and longer tophat, seems like you have exactly that version). Anyway, your best bet is to cut the spring to the desired length and flatten the cut end, just make sure the spring's outer diameter fits in your 500x piston prior to this modification.