Note that since about the time WWII ended shells have been purposely & intentionally loaded in England into hulls longer than the 2 1/2" chambers they were intended, & so marked, to be used in. But what do they know, they're such dumb Brits who "Never" ceased proof marking Damascus barrels for use with smokeless powder.
Note these longer shells were all closed with a "Fold" crimp, thus there was clearance between the end of the loaded hull & the cone, the big secret to using a longer hull than the chamber. The loaded shell should "Never Ever" actually enter the cone restricting crimp opening. This was all settled some 70+ years ago, why dispute it now.
Accounts of all the work done at that time can be read in "The Modern Shotgun". Note that Burrard neither developed the principal, nor did the testing, he simply reported on the vast amount of testing done by the major shell makers of England such as Eley etc.
It is too bad a few people were simply Too Ignorant to understand what he wrote, would have saved them a heap of trouble. Or perhaps they did understand but just wanted to act like they discovered it to try & make a Big Name for themselves.
