I made up ten of five different loads in 0.1 grain increments from 19.2 to 19.6 grains of H110 to see if I could find a more stable load for my 357 Magnum Security-Six. I went to the range expecting winds around 6 mph and got winds at 35 gusting to 45 mph.
The temp was 53F but it felt COLD in that wind. I had to run these loads through the chronograph to get the velocities and standard deviation. i posted a target at 50 yards to have a consistent point of aim and pointed my Lab Radar at the target. I already had it set for pistol velocities and set out to run ten rounds and then start a new record for each load.
The chronograph worked great and even though I was shooting off hand i didn't really expect many hits on the 8x8 target with the wind pushing me all over the place and using five different loads on the one target. I was surprised to find 29 of the 50 rounds landed on the target with five of them inside the 2inch dot.
When I got home and used the computer to download the results from the chronograph I was happy - really HAPPY to find one of the loads produced a standard deviation of 12.81 fps. That is 0.8% (8/10s of 1%) of the average velocity of 1599 fps. That not only more consistent (as far as the testing has gone so far) but also 140 fps faster than the load I was using before. That 140 grain XTP is fast! Although the 19.6 grain load was faster the standard deviation went up to 0.88% of the average velocity. The load below it (19.4 grains) was just over 1% of the average velocity for standard deviation. There were no signs of pressure even with the "max" load of 19.6. The cases dropped out of the cylinder under their empty weight and the primers were well rounded.
I will now continue to test this load under various conditions and on calmer days to see if I can shoot it and if it stays stable.

WOW...seems like you have come close to nailing that ideal load mate.

When shooting 357 Mag, I started off using 296 but found it to be very finicky in that a minute change in load would produce big differences in pressure and also on the target. I next tried 2400 and it was a lot better and more “user friendly”, resulting in good accuracy and case life. I then decided to try an Aussie powder, ADI AR2205...I found my powder. Great accuracy and very versatile across a different range of bullet weights...and pressure signs were non existent.

As it turns out, I believe that H110 is AR2205 made by ADI renamed by Hogdon and your testing parallels what I found when shooting pistol, although I didn’t go to the same detail as you.

That is an awesome result.
I have not yet loaded my 357 with H110 or 2205, looking at your result it seems to be a great load for hunting.
I wonder how good it would be on a 16 inches lever action?

gelandangan wrote:

That is an awesome result. I have not yet loaded my 357 with H110 or 2205, looking at your result it seems to be a great load for hunting. I wonder how good it would be on a 16 inches lever action?

Only one way to find out mate. ADI list it for bullet weights from 110gr up to 180gr in 357Mag from an 18.5” barrel. Nothing to loose and everything to gain.

I worked up my original load back in the mid 70s for hunter's pistol silhouette. The original load used the Speer 146 grain half jacket hollow point and 18.5 grains of 296. That was fast enough that it stayed accurate out to the 100 yards I was shooting. I had to stop using that bullet because it left an indent on the chickens at 25 yards in the shape of the hollow point tip, They said it was damaging the targets, I had to go up to 19.1 grains with the Speer JHP bullet to get similar accuracy. Now, since Speer stopped making that bullet I switched to the Hornady 140 XTP and the accuracy took a dive. SO I got serious about it and used the chronograph to get the best consistency I could. It had worked well with my 9mm and 40 and with my 223.

I definitely would need to find more time for shooting. indeed.

That sounds very much along the lines of,
"Now I'm retired I don't know how I found the time to go to work"

Hard for some eh mate

truly it is a busy retirement life.

I work more hours now than when I was gainfully employed. I just like what I'm doing and who I do it with, a lot more.

gelandangan wrote:

That is an awesome result. I have not yet loaded my 357 with H110 or 2205, looking at your result it seems to be a great load for hunting. I wonder how good it would be on a 16 inches lever action?

gelandangan, H110 performs even better in long barrels. I think you would have golden bullets.