Hello
After I got done with shooting all the .38 Special loads I still had some time to shoot some 125gr JSP .357 Mag test rounds. I wanted to see what effect warmer weather would have on this as well.

The only difference from last time;

357 Mag 125gr Factory Duplication

is I increased the Blue Dot charge from 13.0grs to 13.5grs and N-110 from 18.0grs to 18.5grs, just to test the waters.
The V-V load data says 18.4grs is max.

As predicted, there was no change in velocity with the Rem factory load, although it grouped a little better in the warmer weather. And, although all the loads, with the exception of the AA#9 load, grouped well, none of the loads tested came close to the factory velocity.



Some comments;

17.0grs AA#9……CCI550 primer. Virtually to change in velocity. I noticed just a hint of resistance in ejecting the fired cases this time. This load grouped better in the cooler weather. This indicates to me this load is right up there with respect to pressure as weather gets warmer.

18.0grs Enforcer…..CCI550 primer. Significant increase in velocity and grouped much better. Cases fell out normally.

18.5grs N-110….. CCI500 primer. It’s the fastest handload but I expected the velocity to be higher with this one. 60fps slower than factory but, not bad.

13.5grs Blue Dot…..CCI500 primer. 13.0grs is just as good as 13.5grs. 13.5grs actually clocked a bit slower. Cases fell out normally.

10.5grs Power Pistol… CCI500 primer. Lost some velocity this time, although the group tightened up considerably in the warmer weather.
Kind of interesting to see that 10.5grs of P.P. provides equivalent velocity to 17-18grs of other slower burning powders.

17.5grs 2400……CCI500 primer. Lots of bark and lots of bite! I noticed that increasing charge weight past about 16.6grs, provided very little to no increase in velocity or performance. At least in my gun, there is no reason to go past 16.6grs, although in a longer barrel you would probably see a difference.
Cases fell out normally.
Here’s a pic of a group shot earlier with 16.6grs at 25 yards;





I didn’t shoot any H-110 or 296 this time. I have tried this combination many times in the past and have never been impressed with the velocity as compared to other powders in a 4” barrel 686, although accuracy was generally very good.

So, duplicating this Remington-UMC 125gr JSP load seems to be out of reach, at least in a 4” barrel with these powders, staying within published maximum charges.
I would like to give 410, Longshot, and 4100 a try.. We’ll see.

I ran several of the loads you listed on QuickLoad, and they were waaaay over published max pressure (like 45Kpsi or more). Velocity staying the same, or dropping, with significant increases in powder charge is often a sign of being well into the danger zone of pressure. R,

QL is a nice program but it's not perfect.

These folks;

Alliant Powder - Reloader's Guide

http://www.accuratepowder.com/wp-con...d_data_3.5.pdf

http://www.vihtavuori-lapua.com/pdfs...-Data-2006.pdf

I don't believe would publish loads that produce 45K psi of pressure in a 357 Mag, especially in this day and age.
If I were to fire a load producing 45K, I would have to beat the brass out with a hammer, I would think.
However as it was, the fired brass fell out of the chambers normally and the primers were normal.

I did do some incremental steps last time, not all was posted, and did not run into any of the pressure phenomenon of that which you speak, with perhaps the exception of Enforcer and 2400.
I am familiar with this phenomenon especially in rifles.
The loads posted were only meant for the purpose of illustration and I'm not advocating their use. Everone has to make their own decision on what loads they choose to use.

Anyway, the whole point of this was to show that Remington is using an exceptional propellant and I have yet to duplicate that performance with anything available to me in a handload.

I appreciate your comments.