After posting on the 1922 10-gauge article link, I reviewed UMC catalogues last night while watching TV. During the 1890s UMC only offered 8-gauge NPEs, both paper and all brass. Their first offering of loaded 8-gauge shells came in their 1900 catalogue --
They must have realized pretty quickly that some of those bulk smokeless powder loads were too hot and scaled back by 1901 --
Things stayed the same through 1905 --
UMC then began phasing out the TRAP shell and replaced it with an ARROW shell made for bulk smokeless powder. Previously the ARROW shell had just been made for dense smokeless powder.
June 1909, 8-gauge ARROW Shells loaded with bulk smokeless powder --
June 1909, 8-gauge ARROW Shells loaded with black powder --
