338 RUM.
***Not to take this topic, off target but, 7STW "book" and actual, are two different things, as the 7STW was the king of the Big Seven's, until the 7RUM & 28NOS (factory) were introduced, not including the proprietary 7mm offerings. When I re-barreled my long time 7STW to 28NOS, the 28NOS exceeded it's performance, with 175-195 grain bullets, in a SAAMI chamber.***
***Not to take this topic, off target but, 7STW "book" and actual, are two different things, as the 7STW was the king of the Big Seven's, until the 7RUM & 28NOS (factory) were introduced, not including the proprietary 7mm offerings. When I re-barreled my long time 7STW to 28NOS, the 28NOS exceeded it's performance, with 175-195 grain bullets, in a SAAMI chamber.***