.357 Mag 125gr Montana Gold JHP & Power Pistol

[mobocracy]

Any powder weight suggestions? Yes, there are probably better powder choices but the current component market doesn't make it easy to pick up random pounds of powder and I have 6+ lbs. of Power Pistol on hand. The gun in question is a K-frame 4" Model 66-2.

Speer #13 lists 9.5-10.5 for all 4 125gr bullets and the same thing for the 110gr JHP.

A 2004 Alliant reloading guide lists a max load of 9.2 with an anonymous 125gr JSP.

Hornady 7th Ed. doesn't show any Power Pistol load for bullets over 110 gr, but their 110gr load shows 8.5-10.4 -- lower minimum but about the same maximum as the Speer #13 load.

I usually find the Speer manual prints hotter load data than other manuals; I generally split the difference between the Speer and the Hornady, paying attention to OALs and the bullets in question.

With that in mind, I'm thinking a moderate warm-up load of about 8.5 or so; about 8% under the Alliant max load. Kind of far under the Speer minimum, but it is a K frame and I'm not looking to stop a bear; I have N frames and 10mm autos for that kind thing, and a .50AE Desert Eagle if I really want to be a stroke artist, but I would like more than just a warmed-over .38 Spl +P.

 

[Steve C]

Note that the earlier more generic Alliant data that list 9.2grs of PP as maximum with a 125gr bullet was using a Federal 200 small pistol MAGNUM primer while the current Speer data uses a Speer 500 small pistol STANDARD primer wich can account for a lot of the difference in pressure and top load.

Personally I'd have a tendency to trust the old Alliant data with generic bullets over the more specific Speer gold dot data. The reason is that the loads I've put together with PP in the 9mm and .38 spl have had velocities within expected levels of what the older Alliant data lists when run over the chronograph.

For example a .38 spl with 6.3gr load of PP behind a 125gr Remington JHP using a Winchester standard small pistol primer averaged 1,080 fps from a 4=5/8" barrel of a Ruger BH. The Alliant data velocity of 1,165 fps from a 5.6" barrel isn't too far off actual when you adjust for shorter barrel and diversity between firearms.

Since factory full power (1,450 fps) 125gr loads can and will often crack the forcing cone of K frame .357 pistols its better to use a little lighter load than maximum anyway with 125's.

I'm thinking a moderate warm-up load of about 8.5 or so.

I agree with your thinking, best to work up if you are looking for a particular velocity and to achieve best accuracy.

 

[mobocracy]

I ended up loading a batch of a 100 with 8.6gr Power Pistol and it was a decent load -- grouped well and shot pretty much exactly to point of aim, cases ejected smoothly with no sticking. And it seemed a fairly stout load as well; noticeably heavier than the Glock 17 throwing 115gr JHPs behind 6.2gr PP that I shot as well.

It's too bad the newer Alliant load data has become regurgitated Speer load data. Yes, same company under the hood, but I'd at least like some diversity of load data.