I'm with Milt on this one as I don't really worry so much about pressures as long as they are below my own personal thresholds. But I load for every gauge I shoot because I feel my ammo is as good if not better than any off the shelf fodder. I also can't find the loads I want when I want them, so I go down to the loading chamber and crank 'em out by the 100's.
The commercial ammo manufacturers (except RST and other boutique loaders) have never been clued in on the pressure thing because they don't have to as long as they stay within the SAAMI limits for each gauge. Our guns fall into that boutique category. The rest of the shotgun world does'nt give a hoot about pressure or recoil and how it affects their modern guns. In reality it does'nt matter to them as long as it goes boom and the target or bird is hit. Gary is correct in that velocities and pressures in factory ammo will vary from lot to lot by virtue of differences in powder density, interior hull dimensions, wad composition and primer brisance, just to name a few.
The bottom line is it's your gun buy what you like and shoot, shoot, shoot. It's all good. If you worry about pressure and recoil, and you should if you are shooting a gun made more than 50 years ago, either you buy the boutique ammo or load your own. It's not rocket science and there is a tremendous satisfaction of bagging your limit or shooting a good score on the clays field with your own ammo.
Oh, by the way just to reiterate, pressure and recoil are not related. I don't care if you are shooting a Benelli 3 1/2 super jam-o-matic or a H&H Royal but they do matter and if you would stay on the low end of both, you and your gun will be better off. Don't get me started on 1400fps. or 2oz. turkey loads.
Nice photo Uncle Gringo Milty. I'm sure you were'nt hammering one of your Smiths with that South American ammo.
Mark... Where did you dig up that photo?