I recently purchased a PPG reamer in 375 H&H in order to make Wilson-type chamber seating die. Fortunately I have the help of my uncle, a retired tool and die maker. However, he has never had to use a tapered reamer and has never cut a rifle chamber. My question is: How much metal can these reamers be expected to remove? It seems to me that if after drilling a .377 pilot hole, the reamer would suffer tremendous wear if a series of larger holes were not drilled first. Any help is appreciated.

The reamer you have is quite capable of doing the entire job, the only drawback being it will take a fair amount of time do to having to remove and clear the chips every .050-.100 depending on how the reamer handles the chip load. Many rifle barrels are chambered completely with only a finish reamer.