Relying on memory here but I had a Moss 44US(C) - very similar - and I wonder if you have taken the bolt apart and cleaned it? The firing pin channel can get gunked up and require significant cleaning. Also, you have good advice here but there are also Mossberg experts over at Rimfire Central - http://www.rimfirecentral.com/forums...splay.php?f=51
- as well as the parts needed at http://havlinsales.com/
, as previously suggested.
In addition, doesn't the 44US have an adjustable trigger? As I recall, it is very easy to pull the stock off of the rifle and gently play with the screw to set the trigger at a level that you like.
You WILL like the 44 US series. Great rifles