Sounds like you have it sorted now. Excellent. If you haven't already done so, whilst the trigger unit is out of the gun, clean it out to remove any gunk that's built up over the years. The grease used at the factory can go hard and gum things up a fair bit.....Use a de-greaser / GT-85, or similar. Let it dry. Then lube with light oil (gun oil, 3-in1 etc.).