Re Bell's "long shell in short chambers" tests, the average increase was 738 psi as a result of the longer hull. The greatest increase was 1,216 psi, and there were 3 others within a few psi one way or the other of 900. There were also a couple that showed an increase of less than 350 psi. Bell also pointed out that simply lengthening the forcing cone without lengthening the chamber would eliminate much of the increased pressure.

Assuming no forcing cone issue, and assuming you build in enough of a safety cushion by working up lower pressure reloads, you shouldn't have a problem shooting longer hulls in shorter chambers. I've done a lot of that personally and have never had an issue.