The question came up on another forum about how much velocity you should get out of a 158 gr. 357 magnum in a rifle. One highly respected reloader says he is getting 2000 fps with Hodgdon's recommended load of 18.0 gr. Lil Gun.
Indeed, Hodgdon claims that Lil Gun produces 14,900 CUP less than H110 when loaded to about the same velocity in the 357 with a 158 gr. Hornady. That sounds too good to be true and you know what they say about things that sound too good to be true.
Still, I have not tested that particular combination, so I cannot confirm or deny it.
I will point out that Lil Gun did not produce these amazingly low pressures in other cartridges that Hodgdon tested. Are we supposed to believe that the laws of physics are different for the 357 ???????
I will point out that Lil Gun did not produce particularly low pressures in my 357 cast bullet loads -- in fact, when loaded to the same velocity, Lil Gun and WW296 produced about the same pressure, as measured by a strain gage.
I will point out that when Hodgdon or anyone else introdues a new powder, they don't automatically retest all their old powders. In other words, Hodgdon's H110 data may have been tested years before the Lil Gun data. Since they should be recalibrating their pressure barrel every time they use it, it's conceivable that the lower pressure claimed for Lil Gun could be due to a difference in calibration. That makes more sense to me than any other explanation. That's why, when you are doing a comparison test, it's always better to load all the cartridges at the same reloading session and shoot them at the same range session.
I will point out that Hodgdon is still using the obsolete copper crusher method and we don't know how CUP correlates to PSI in the 357 or if it correlates at all. The SAAMI spec is 35,000 PSI or 45,000 CUP, so you would assume that 35,000 PSI = 45,000 CUP, but don't bet on it.
I will point out that Quickload pressures do not agree well with Hodgdon's data or with Winchester's data. Maybe Quickload is wrong, I dunno. The only thing I am sure of is that it is hard to get good pressure data in the 357.