58 Remington Euroarms a little help please

[Sundance]

Had this problem a few weeks back after  GOOD clean its seemed fine.  In the mean time I orded a new trigger and forked spring thinking replacing the aforementioned might solve.  Anyway problem occured again today and decided to replace trigger, works fine until I put the cylinder back in - can't understand this?  I thought that forked spring might have got weak so tried to change that, however longer part of spring that goes against the trigger is longer than original just about fits, but to no avail.
If the gun locks on full cock etc.. all seems fine why won't it work with the cylinder in?  This has got me stumped.  I think its going to be a gunsmith job as I'm out of ideas.
Can any of you good folks offer an explanation, or advise further?
If I file down spring will I need to heat it to give back strength etc..?

[Sundance]

Just put the original trigger back in and its working fine, however very, very sensitive let off - real hair trigger
Hhhhhhhhhhhhmmm.   Not sure if I can live with this, and suspect I'm going to encounter the same problem with use..

[Sundance]

I just used a Dremel on that forked spring - did it slowly though  it did'nt heat up.  Fitted the new trigger and spring and the let off after some light Dremel work on the trigger - it was a mile off being right, and a polish with very fine wet and dry all seems right.  Just hope I haven't messed up the temper of that spring.

It's more satisying sorting it yourself than handing it to a gunsmith..