While what Buffalo Bore states is true of 38/55 brass over 375 brass, ie it has greater capacity, that comes at the expense of strength in the head area. If you goggle 375 vs 38/55 brass you’ll see images of sectioned 375, 30/30 and 38/55. Sure 38/55 provides greater capacity but I’ve found 38/55 brass shows pressure signs quite quickly too and prefer not to use 38/55 brass for high pressure loadings.
If you really want a case capacity increase and strong brass, then the next logical step is ream out the chamber to 375/356. This provides a considerable increase in case capacity. You also need to work the internals to feed the wider case. To my mind this is the big bore that Winchester should have released. For dies I use Redding 375-308 dies and a 30/30 shell holder. This would be a practical alternative for those of you considering a re-bore. Even the 375Win Lee FCD works on the 375/356 case.
Last edited by JFE; 05/02/20.
