Both factory and custom can produce good or poor shooting barrels. It's a case of barrel roulette. I have had a factory .260 barrel significantly outshoot a heavy EABCO barrel and a factory .243 barrel that significantly underperformed vs a standard taper EABCO barrel. Same for a fluted MGM 357 max barrel that could not keep up with several H&R handi rifle barrels. Every barrel is it's own creation. Buy them, try them, keep the good and sell the average.
