I have on my desk before me the 1947 Second Edition of Major Sir Gerald Burrard's
The Modern Shotgun, Vol. III The Gun and the Cartridge, and give full recognition to his exhaustive research, support from Imperial Chemical Industries, and personal experience.
HOWEVER, shotshell performance and ballistics changed substantially in the U.S. 50 years ago after the following:Remington SP high density polyethylene compression formed hull with a separate base wad was introduced in 1960. The polyethylene Power Piston Figure 8 wad (Patent 3,217,648) in 1966. The one piece RXP with an integral base wad in 1972.
http://books.google.com/books?id=scA6lVmzQA8C&pg=PA21&lpg Winchester/Western introduced the Mark 5 polyethylene shot collar in 1961, followed by the one piece compression formed plastic hull for the Super-X in 1964 and AA Target shells in 1965.
The Federal Riefenhauser (straight wall) plastic shot shell was introduced in 1965.
Previous threads on this and other forums have also shown examples of modern plastic 2 3/4" hulls which when fully opened were shorter than 2 3/4". On Sat. I'll do some trash diving after shooting skeet out at Ben Avery and collect an assortment of shells and post an image and measurements thereof.
