sharps4590,
Thanks for your post.
In many ways I feel (rather than think) the same way you do. Have both stuck to 2-1/2" shells in short chambers, and also some roll-crimp loads.
But eventually also shot plenty of 2-3/4" shells of appropriate pressure, in older shotguns/drillings with "short chambers," including some over a century old. However, I did have them checked out, and sometimes tightened by top professionals, before using the "modern" loads. Never had a problem. (Of course, am also aware of Sherman Bell's pressure tests, which are very interesting!)
Have also talked to more than one top-notch shotgun smith, including one who's worked on hundreds of British "bests," who says lengthening chambers in older guns "to reduce pressures" can result in the barrel thickness at the front end of the chamber can become too thin to contain pressures of SOME newer shotshells. In other words, "fixing" short chambers due to the old myth can make older guns unsafe.
