Thinking about loading up some hot and heavy loads for my four inch 681. Speer lists a silhouette load, 180 grain full jacket over 14.5 -16.1 grains of H110. They list it in a separate section between the regular .357 and the .357 Maximum. The cylinder just makes the minimum length of 1.625" recommended. They warn only to use this load in "heavy frame" revolvers. If I recall correctly, pressure approaches 46,000. Are we talking N frame only?

(Nosler lists a similar silhouette bullet or a partition over 16-17 grains of H110, without any special warnings).