I installed a new "domed" strain screw in my 15-7, and the trigger pull became very tough and the return sluggish.
I noticed that even in new Smiths, the strain screw is flat on the end.
Do these need to be "fitted" or filed flat? I don't get why they dome the tips only to file them flat at the factory. I don't think the pressure of the mainspring can flatten them that quickly.
I also pulled the stainless strain screw out of my 64-7 and it was mushroomed, do they do this to a certain point and then stop?