I have built guns and smithed near 30s years, many of those as a daily profession. I have a whole book case of reference books. I know for sure, I have never heard of a Hornet being dangerous in one, and used the Howe reference as a professional shop apparently not having any problems. I would have to suspect thousands have been converted over the years.
I dont doubt you have seen two cracked, the question would be if there was some other factor , actions in a fire perhaps, lots of things are possible.
If we consider how many 218 bees, I suspect thousands at least, some even the improved version that the Low Walls have been converted too as well, and its zippier than the Hornet, I simply fail to comprehend how some more warnings have not been published, than seem to exist on the topic.
Its an interesting topic for sure. Frank de Hass talks of converting Ballards to the Hornet, as long as the FP is modified, an obvious need for the Win Single shots as well. I have to wonder if the ones you saw damaged had been modified. As far as I know, the Ballard ran similar rounds as the low wall, but admit having not studied the Ballard to the extent that I have the Win singles shots.
As far as pressure, consider this. In Phil Sharpes "handloading" he shows pressure levels for several rounds that we know the Low wall came in, 25 20 Single shot for example and shows loads ranging from 12,000 to 25,000 and actually even higher "for strong actions".
Another one the 25 20 WCF, lots of known examples of Lowalls can be found. same pressures shown, up to 32,000 in his tests, no mention of rifle action strength.
That force against the breech face is directly related to cartridge rim diameter is well known. While rare, at least one Win lowall is seen in Madis book in 32 40 WCF. Now this is one I HAVE HEARD is "they never chambered it in a low wall, " yet Win apparently made them if Madis knows peanut butter from horse apples. And granted, Madis early books on Wins are full of later discovered errors, proven by later research, but I imagine his picture and description is factual.
Now the kicker is, Sharpe shows breech pressure for the 32 40 in loading data, in the 25,000 level. Sharpe was no wall flower on guns or cartridges either, nor were any of the other sources I have referenced.
But if 25,000 will crack any and all low walls, I fail to see as too why these other multiple examples did not either in even larger rims size, and similar pressures. And its only reason, that them early reloaders loaded off Sharpes data, using all the rounds in discussion.
Maybe its simply an "early gun" versus "late gun issue". Maybe once they converted the FP to the Mann or perhaps its the Niedner type, that cured the cracking problem, of which as said, this aint my first rodeo by a long shot, but I have never heard of it surrounding the Hornet in a Low Wall. And there are likely other things I have never heard of as well. ;D
Joking aside, I am not being argumentative for that sake alone. I was really interested in your reasons for caution on the Hornet in the Low Wall.
If you have other evidence, please enlighten me, I always am open to interesting technical discussions on rifles, but I feel I have posed some interesting counter points for consideration as well.
thanks, Ron