Keith;
I recall the Smith test that Buck did. It was reported on in the Lefever Arms Collectors Association newsletter some years back. He also did another one on a Lefever. As I recall he began with the heaviest load of Blue Dot listed in the loading manuals & went UP from there. My recollection on the Smith is that he stopped when the gun began blowing open at every shot. When testing the Lefever it stayed shut & he did go to the destruction point on it.
As I recall he was loading either 2 or 2¼ oz of shot & with those powder charges he was way above & beyond what an ordinary 1¼ oz load will stress a gun.
Back around 1970 I had a set of Boehler Steel barrels fitted to my FE Lefever 12ga. I have fired a fair amount of the 3 3/4-1¼ loads through it since then. It does have Italian "Nitro" proof marks on the steel set of barrels.
My hunting does not generally call for that heavy a load. I used those when I was doing a bit of Duck Hunting. "IF" I could have got the 3¼- 1¼ load in anything larger than #7½ I would have used them. I did end up reloading so I could use less velocity behind the heavier shot charge, but the gun handled the heavy Factory load just fine.
I am certainly not going to disagree about the durability of OLD WOOD. In fact my statement was the wood was what I would be concerned about. Even that old Junker H Lefever I mentioned does Not show any signs of metal Peening. As I mentioned with the ball joint hinge completely removed the gun will close tight with virtually no shake or movement from the bolted Doll's Head alone holding it shut. I of course have no idea what loads it had fired in the past. It has the barrels Lefever cataloged as "Best London Twist", though they were no doubt made in Belgium. I would pretty nearly though Bet the Farm they were not all PussyCat loads.
I fully agree everything has its design limits. Old JD Hydraulic cylinders for instance from the 2-cylinder era used pressures below 1K psi & had leather cup seals. Put them on a modern tractor with pressure in the 2K-3K range & they won't last long. 1¼ oz of shot was however a common load for the 12 gauge in the era the Smiths & Lefevers were built. Those old loads using 1¼ oz pushed by 28 grains of Infallible or Ballistite , 3½ drams measure of Schultz or Dupont smokeless are not Light. These are all recommended loads straight from a Lefever catalog of the day.
I have never loaded shells below around the 7-8k psi range when loading smokeless, even for Damascus & Twist. As of yet have seen no reason to do so. Pressures much below that are outside the Design Element of most smokeless powders. Smokeless doesn't ignite as easily as Black & burns with a differing characteristic. It also needs to be used within its design element. With the exception of very fast powders such as Bullseye or Red-Dot this does not include 5K or less loads. Those pressures are simply playing on the ragged edge of design for the slower powders.
