What caliber and what MV? You may just slow it down a bit.
Higher pressure loads cause increased copper fouling?Ok back down to a lower node and see if the copper fouling decreases. Many will shoot better at the lower node anyway.
Its pretty obvious that really rough throat is your problem, high or low node I seriously doudt its gonna matter untill your rough throat is addressed.
My 2 cents anyway
Looking at your pics it appears the reamer had some very fine chips out of it, that reamer either needs to be reground or thrown away.