The new heavier trigger spring for Contender frames was introduced (as a liability deterrent, I'm sure) in 1997, according to an e-mail I received from T/C Customer Service Manager Tim Pancurak.
The older frames with the original springs could be adjusted to a perfect, no-creep no-backlash surprise break of around 2 lbs., safely. The newer ones won't go below about 5 lbs. And of course the whole discussion is moot, because effective Jan. 1st, the 'newest' Contender has no adjustments in its trigger at all...it's as bad as the hated Encore.
You can buy lighter aftermarket springs( I think Brownells has them, and probably SSK,) but installing them yourself isn't easy.
I'm holding onto my two old frames. Maybe somebody hasn't gotten the word yet and you can buy theirs. Watch the prices of 'originals' go up...