From my experience, the old paper shells were much closer to the stated length on the boxes then modern day plastic shells. Doesn't matter whether it was roll crimped or pie crimped a 2 3/4 inch shell was 2 3/4 inch when fired. All the companies, Remington, Peters, Winchester and Western introduced the "New Remington crimp," "New Peters Crimp,"
New Flat-Top Crimp.jpeg
and "Super-Seal Crimp"
Xpert Super Trap & Super Skeet brochure, steel heads.jpg
Super-Trap folder cover.jpg
on their 12-, 16- and 20-gauge Skeet and Trap loads in time for the 1939 GAH, with the new crimp appearing in their 1940 catalogs. The new crimps began appearing on hunting shells after WW-II, Remington and Peters a bit sooner than Winchester and Western.