I have an 870tc that was made in 1988, I only shoot about 2000 shells a year through it. When you set it on its buttstock uncocked the pump falls down about 3/8" it locks up tight and will not open when cocked without depressing the lever to open it. I have had it to 2 gunsmiths and they say don't worry about it. I don't see any other 870's at the range doing this regardless of age. I also have an 870 express that is doing the same thing. Do they need repaired?