I think the main thing here is that factories have so long warned us against using longer shells in short chambered guns. This was however based predomintely on the "Load" on the inside of that longer shell, not the length of the case itself.
A similar thing existed with shooting "Ball". Most Muzzle loaders were cylinder bore & it was common to mold balls to about .010" under bore size. As choke obring came in fashion shortly after breech loaders came into general use it was not considerd desirable to stuff a .719" ball into a shell & fire it through a .690" choke, so choke bore guns began to be marked "Not For Ball". Of course as long as that ball was smaller than the choke no problem existed (other than accuracy) so that mark was dropped over 100 years ago. Even today I hear people say it will "Ruin" a full choke bbl to fire a Foster Slug through it even though they are purposely built to go through the tightest choke they are apt to encounter. Many "Facts" were based on a certain set of circumstances, but once ingrained its a long battle to get folks to accept they are not applicable to "Different" circumstances.
