This has got to be one of the worst Adaptions of a true story I have ever watched. The producers and director should have paid the extra money to have a military representative on-site. If not that, then at least someone who had a clue about firearms. Lever action rifles were never issued to American troops in Europe. Even if they had been, you can't shoot a Henry multiple time and never work the lever. It might have been a good movie had anyone associated with it had a clue about the military or World War II. As far as believable, I would put it on the same level as Howard The Duck.
Review of D-Day Assassins
