Funny you should ask. Being the worlds luckiest guy, I have alittle experience to share with you regard this & more.
I just received back from a famous gunsmith, a Bat action, die blanks and 2 Border barrels. I say the gunsmith is famous because there is surely nobody shooting a custom, who hasn't heard of him. I sent him a full reamer kit -Rougher, finish, sizer, 10 pilot bushing kit, a floating reamer holder, go/no-go guages, and prints. All stuff sent was brand new and verified perfect. He had 2 months to finish the barrel blanks.
3 months later my stuff arrives engulfed, every nook & cranny, with grime. One barrel was not headspaced correctly,I can't close the bolt with the GO guage). All chambers are oversize, including my dies. My GO guage, boltface, and sizing die are galled,from use while grimey).
There were other problems, but how did this happen?
Well aside from inattention to detail, lack of cleanliness, and poor work standards, the only things returned to me UNGRIMED,therefore -not used), were the ROUGHER and SIZING reamers.
So I would agree with DANTEC.