By the fall of 1861, lead shortages in Richmond had become so acute that Tredegar warned that they might have to cease the production of Archer and other lead-saboted projectiles. This was the primary reason for the abandonment of the Archer. In response, around Oct. 1861 Col. Gorgas sent a memorandum to all Southern arsenals declaring the Read shell with a cast-in iron cup would be adopted as the standard for both heavy and field ammunition. Samson & Pae had already started the production of 3.35 inch Read shells for the reamed & rifled old iron 4 pounder guns. It had a pre-rifled wrought iron sabot as Dr. Read prescribed at that time. But so many of the current 3 inch Rifles were bronze guns, the Ordnance authorities decided a new shell must be adopted with a softer copper sabot so as to wear out the bores as quickly as iron. In Dec. 1861, they announced a new projectile for all calibers from 2 1/4 inch Mountain Rifle Gun to the 4.62 inch Rifle Siege Guns, with copper disc sabots supposedly based on Dr. Read's patented design. The concept had been brought to them by a Mr. Mullane, a civilian ordnance worker from Tennessee. In fact, Dr. Read's 1856 patent mentioned the possibility of bolting an expanding cup onto the iron bottom of a projectile, but he did not recommend it. The geniuses headquartered in Richmond believed they were introducing a fine "Read" projectile. They ignored the drawings and reports coming from the Deep South showing the excellent performance of Dr. Read's cast-in copper cups. And thus, we got the beautiful, but inferior, series of Mullane projectiles. At the time, Tredegar was casting nearly all field-caliber rifle shells and they switched from making Archers to Mullanes in mid-February 1862.
The concept wasn't entirely bad as they were supposed to use a 5 inch diameter piece of sheet copper formed like a saucer to fit into a 3 inch bore. Theoretically, that would allow the sabot to expand laterally into the rifling when it was driven forward by the propellant charge. This was an essential part of Dr. Read's design as can be seen in the high-band configuration of his Deep South Read sabots. But in practice, as can be seen on hundreds of excavated examples, the disc was compressed and driven forward leaving a narrow edge of copper to catch the rifling. The foundries were ordered to adopt Read's superior cast-in copper cup in August 1862. Some continued to make these Mullanes into the late fall of 1862 (see the last page pictured below). I have found no evidence of any test firing in VA except for when they proofed new guns. Yes, the sabots frequently ripped off but I suspect their primary problem had to due with faulty fuzes. A limited supply of large caliber Mullanes continued to be made until the end of the war. At some point in 1864, the heavy copper sabots were replaced by iron which reportedly worked just as well. The 3 inch Mullane or "Tennessee sabot" shell was primarily made in VA. For the first few months, they had no flame grooves. Most of the Deep South foundries made actual Read projectiles instead as they were set up by the inventor.
Additional info can be found in the captions, below. Over the years, I have been fortunate to find three 3 inch Mullanes.
Woodenhead
