Re: Masters for New (ACW Union) US Infantry on the March
The slope arms are a bit vertical on the models and look from the pics as if they are balancing them.
The US Army did not use "slope arms", period. Shoulder arms was the norm, with the right hand wrapped around the trigger guard and the rifle carried vertically, tucked in to the right shoulder, as per Hardee's Manual.
Some Virginia units in the CS Army used Gilham's manual where the rifle is carried sloped back over the left shoulder, left hand gripping the butt as in these figures.
The other most common position used for movement at the double quick, was "right shoulder shift": the rifle is held with the right hand under the butt and angled to the rear and left, behind the soldier's head