KM, look at the 338 Talbot, it´s a modernized 338/50BMG. It was a true barrelburner. According to Cartridges o t World there was severe erosion after only 150 shots. A 30 caliber would be even whorse. I think that the 375 is the smalles bore that work with the big case with the powders available to us. The 375/50BMG is also called 375 Mach V, I belive.
Jerry. Is WCC872 slower than Vihtavuori 20N29?
Thanks, AKI