Carl's Bullet & Shell sales site recently posted a Houston Read shell with the same saw cuts in the sabot typically associated with the many late-war Broun shells found in Virginia. I made up the first page shown below using Carl's photos and information. So, that brings up the question - where did the idea originate? I had always assume credit was due the self-promoter Col. Broun of the Richmond Arsenal. But upon further investigation, it is clear the concept came from Cols. Raines and Girardey at Augusta Arsenal. Along with Maj. Mallet operating out of Macon, GA, they were the closest thing to a brain trust for CS field artillery projectiles in the South. When the great Rebel artillery commander E. P. Alexander lodged complaints about the poor performance of their 19 pdr. Parrotts and Reads at Chattanooga and Knoxville, he wrote directly to Augusta for help - intentionally bypassing the authorities in Richmond. The saw cuts in the bottom edge of the sabot was Augusta's idea.
Check out the third and fourth items pictured below. This Second Report of the Board of Artillery Officers was the result of extensive field tests mostly conducted during late 1863. They published the results in early 1864 - I believe to emphasize the importance of their conclusions which had largely been ignored by Richmond. Among other suggestions, they called for shorter 10 pdr. Parrott ammunition because they were regularly tumbling even when the sabots took the rifling perfectly. Note on the last page below they call the "safety groove" between the copper sabot and iron bottom of the shell a "lubricating ring." I call it an "expansion ring" for obvious reasons.
W.H.
