Originally Posted by
Kosh75287
Alliant CURRENTLY lists 14.8/2400 as their max charge with a 158 gr. bullet, though a jacketed one of hollow-point design, seated to 1.575". It yields 1265 f/s from a 10"(!!!)barrel, probably un-vented. I wonder the following things (without really expecting any concrete nor confident answers):
1.) Would the use of a (higher-lubricity) hard-cast LSWC with an identical load yield a higher velocity +/- lower chamber pressure, without serious change in accuracy?
2.) Would seating either 158 gr. projectile to the SAAMI Max 1.590" (cylinder length allowing) lower chamber pressures sufficiently to warrant exceeding the 14.8 gr. upper-limit charge weight by up to 0.5 grains?
3.) If we're "maxed out" in our use of Alliant 2400, would abandonning tradition for the use of other propellants, such as 300-MP, H4227, H110, or VVN105 or N110 enable us to get closer to the original factory specs, without shaking apart our 6-shot N-Frame S&Ws, .357 RedHawks & Blackhawks (6-shot ONLY), T/Cs & F.A. Single actions?
MY answers, in the absence of testing, are "Probably", "Maybe", and "It might be worth trying". respectively.
The cold realities of MY situation are that MY .357 Magnum has a 4" barrel, and I'VE NEVER been able to get 2400 to burn completely in ANY handgun caliber, in ANY barrel shorter than 7.5". I don't know if it's worth blowing yet more unburned powder through the tubes in pursuit of the original (if memory serves) 158 gr. @ 1450 f/s from a 6.5" barrel, nor 158 gr. @ 1550 f/s from the 8 & 3/8" barrels. I guess that's up to the individual reloader.
Early on, I, too, tried the 13.5/2400/158 gr. SWC load in .38 Special cases and it clocked in the (VERY) low 1200s in my Police Service Six. I tried the 15.0/2400/158 LSWC (max recommended, at the time) and got just under 1300 f/s from a 4" barrel. I ended up using 8.0/Unique/158 LSWC, or 9.4/Herco/158 LSWC, and obtained velocities clustered very closely around 1280 f/s. Since 1982 (when I bought the revolver), I've run a fairly steady diet (over 60%) of the latter 2 loads through my PS6, despite both loads later being revised downward. My revolver shoots as well now as it did in 1982. No looseness, no end-shake, no nothing. That's according to various gunsmiths, not me.
YMMV