Transfer port seal

[Roger5]

My .177 TDR transfer port seal is leaking, had it apart today and replaced the seal, unfortunately, this hasn't cured it, took it apart again, and replaced the seal with a 6 x 1.5 instead of the original 6 x 1, this cured the leak, but now the bolt Housing sits proud, and to refit the barrel band I had to push the barrel down slightly, obviously, I'm not happy with that, and have now ordered some 6 x 1.2 seals to see if any better, anyone else had or seen this type of problem before ?