[Goatwhiskers]

While waiting for materials to come in, once again got to thinking (sometimes a bad thing). I'm building up a cadet Martini in .357Max, 24" 1 in 16" twist barrel. I notice that the little bit of data I have on the cartridge is loads for pistols, using "pistol powders" from the faster burning end of the spectrum.`Would there be any advantage to moving to a slightly slower powder to take advantage of the longer barrel? I'm not gonna suggest any particular ones yet as this is a theoretical question for now. Goatwhiskers

 

[kludge]

Yes, there can be a benefit. I think people are getting some numbers in the range of 2200-2300fps with A1680 and 180gr SSP. It's a little too slow for my 9.5" SRH .454 but it meters great and shows good accuracy.

 

[broom_jm]

Reloder 7 and Li'l Gun are also good options for a 357Max and longer barrel. 23 grains of RL-7 would be about the maximum and 21grains for Li'l Gun. Please reduce both by 10% and work up.

 

[COSteve]

Like the 357mag, the 357max works well with Hodgdon's H110 and H4227, their slowest burning magnum powders, in longer barreled firearms. Hodgdon's load data site recommends both for the 357max.

 

[Rocky Raab]

The longer barrel itself will give you the most boost, simply because the high-pressure gas has a longer distance and time to act on the bullet. That increases the velocity.

Going to a slightly slower powder can add a wee bit more, but the burn rate is only an indirect reason for it. The real reason is that you'll be able to use more of the slower powder, and more powder can produce more gas to do the pushing. Burn rate tailors how long pressure stays high, not how high the peak is.

In a given cartridge, one or two powders will prove to be optimum. It depends mostly on bullet factors (bearing length, material, diameter and weight among others) and on case volume.

BTW, the reverse does NOT hold any benefit. It does not pay to move to a faster powder for a shorter barrel. A faster powder means less powder and thus less gas produced. That in turn means less total "push" regardless of barrel length.

 

[BackWoods Billy]

Thanks Rocky..I learned something today...