To get a brush out of a .50 caliber barrel - take an empty 45-70 shell case, file the rim off, drill out the primer pocket to accept a 10-32 screw, use a 1/2" 10-32 screw to mount the case on the end of your ramrod, push it down and force it over the brush so that the brush is inside the shell casing, slide the whole works out.
