You're a tougher man than I, Gunga Din. There is no way I'd want to touch one of those off in a LCR.
FWIW, here is a screenshot out of my Hornady 10th edition on the 125 grain XTP's.
I too have noticed the discrepancies. I have not tested extensively, but have done a bunch of research on this powder. I believe the recommend by the water cooler brigade on the errornet is not to download below 3% of max load data. But this fellow pointed out something pretty germane:
Maybe you'll find that helpful. COSteve has been around for a long time and I've corresponded with him a couple of times. He shoots his 357 carbines out to about 300 with his peep sights and has given out some pretty good advice over the years on this cartridge and firearms that shoot it.
EDIT: I forgot to add a rebuttal:
Well, now it's clear as mud...I feel like calling Hodgdon.
You've probably heard this too, but H110 is pretty slow burning and isn't completely burned on these shorter bullets. This can lead to forcing cone erosion and top strap flame cutting. Honestly I think you'd need to shoot a lot in a current L frame sized revolver...not so sure in a LCR though...just something else to keep in mind. This is one reason I think I'm mostly going to use it in 140 grain on up.
Disclaimer: I have NOT done much with H110, but I have it and want some barn burner loads for use in L and N frame sized guns. It's on the agenda.
This bugged me so much I called Hodgdon.
Here is their load data:
125 GR. HDY XTP
Starting Loads Grs. - 21.0 Vel. (ft/s) 1,881 Pressure 38,400 CUP
Maximum Loads Grs. - 22.0 Vel. (ft/s) 1,966 Pressure 41,400 CUP
Bullet Diam. .357"
The fellow I talked to, Shane I think, he said that they used to recommend a certain percentage below max load but no longer do that. He said a rule of thumb used to be 8-10% below max, but at the have more precise means of measuring pressures and more data over the years they have completely dropped that "rule of thumb" on load data.
He also said that the H110 powder is finicky and hard to ignite, so the greatest danger is not getting a clean burn if the charge is too low. This can lead to squib loads, or even more rarely a partial burn, smolder and then re-ignite. I said "so a hang fire?" and he said yes. I asked him too about the old "KABOOM" detonation reports. He said these are much more rare but there is some truth to having a too small of a volume charge in a cartridge that it can burn across the top and cause detonation, but it's extremely rare. I threw out "so like a one in a million chance" and he replied in the affirmative but nobody could really know that actual number. Could be higher, could be lower.
I asked him about the discrepancy in their load data vs other manufacturers, like Hornady. He said he's sure they probably got along just fine in their load testing and had good results, but with this particular powder they definitely don't recommend reducing from their starting load. He said using someone like Hornady's data one could fire thousands of rounds without any issues, but then you have that one in ten thousand chance of a squib load...
Very interesting. If I had a LCR I was looking to use these in I think I'd be firing them from a larger revolver first just to get a feel...or there is always Alliant 2400 for the smaller guns. I used that some in my SP101.
I noticed interesting thing from this thread. I noticed that in the pic the values for H110 and 296 are different on the low end. I was under the impression they were the same powder, just labeled different.