I've said this before and I will say it again, most problems with a HOT is that the gun was taken apart by a gunsmith that did not know L.C. Smiths and the Hunter One Trigger. There are three screws that can cause this trigger to not work or not work correctly.
In putting the stock back on, the top tang to trigger plate screw has to be just right, too tight and it will cause the trigger housing plates to bind on the sears. This screw has a tapered head and has to be orientated to the slope of the top tang, so this means one full turn.
The next screw, rear trigger plate to rear of top tang. This screw if it is sticking out of the top tang is doing the same, binding the trigger plate to the sears.
The third screw is one that is the most common problem when the locks are taken off, the lock plate connecting screw. One half turn will make the HOT double or not work at all. Since all screws to an L.C. Smith, even the lowly Field Grade farmers implement gun had all screws orientated.
If you have ever had a stock off a gun with a HOT trigger and seen how much more wood had to be removed for it to fit, you would wonder how it could hold up. Not only was more removed, but where the selector bar is, a small hollow is put on each side for the bar to be able to move for left or right switching.
The HOT is an excellent trigger if left alone with very few moving parts. Of anything to go wrong is the thin wire spring on the spur lever.