Safe to say that most people don't have the knowledge or instruments to measure the pressure or recoil. Some die-hards do send their shells away for pressure testing. But then I've read lengthy threads that say having somebody else test your load will only tell you the amount of pressure your shell generates in that person's instument, but not necessarily the pressure within your gun (enter differences in chamber dimensions and, dare I say, forcing cones).
So where does that leave the mere mortal? To make judgements based on the information we have, namely shot weight and published pressures. In the case of factory shells, pressure data may or may not be available, leaving us only with manufacturer's promises of "light" or "for vintage guns".
I think chamber dimensions should not be of much significance. If I recall correctly, the difference in chamber diameter, standard American 12ga vs British 12ga, is .002"--so little that Brit hulls work in Yank doubles, no problem, and vice versa. And a bunch of people, from Burrard and Thomas on up to Bell, have played enough with long shells in short chambers to show that, to borrow a phrase from the late Michael McIntosh, that's a fairly friendly troll--as long as the pressure is safely within the parameters for the gun in question. Increased pressure because of the long shell/short chamber combination seems to run in the vicinity of virtually none to a few hundred psi. In other words, not enough to hurt as long as you leave yourself enough cushion. And as long as the gun in question does not have one of the older forcing cones that approaches a right angle rather than a taper.
Last edited by L. Brown; 01/17/11 04:54 PM.
