Unfortunately, it sounds as if all your initial problems with the bolt not closing was due to your 3/8" drive socket (I had to turn mine down, then found a 1/4" drive works great) the larger 3/8" hits on the thread in the action. This gave you a bad taste right off the bat, but may have just been you?
I too am surprised you bought another Mtnr barrel - guaranteed no difference in tolerances from GM.
As, to your trigger. Sad, but I don't think anyone took you trigger as what Sabotloader has shown are what they offer is what you have and had. I could imagine they took it off when disassembling the rifle and inadvertently put a different one on.. As to defective, if it was like the other issues you have stated - doubtful you took the time to adjust.
Now, you trashed which was most likely a perfectly good barrel?
I bet their experience was as good as yours.
Last edited by 52bore; 12-25-2017 at 03:22 PM.