For what it’s worth, it took me several hours over the course of 2-3 days of slow inletting using inletting black to get the barrel fully seated on my Chambers York County rifle kits. That’s not a knock on Chambers kits. Unlike the Kibler kits, they are not designed to come together without some substantial final fitting/inletting on the assembler’s part. Think of it as a “middle ground” in terms of difficulty/work required between assembling a Kibler kit and building a gun from a blank.
Also, when I built my first one, I bought the assembly video Chambers offered for sale which was very helpful as a first-timer.
Good luck.
Jay