.357 Mag Powder

[dhoobler]

I was just testing .357 mag loads this past weekend. I had some accurate #9 sitting on the shelf and I wanted to use it up. I had plenty of odd brass and some Winchester magnum primers. I used the starting load, 11.2 grains under a Hornady 158 gr LSWC, according to loading data:
http://www.accuratepowder.com/wp-conten ... eb-REV.pdf
which lists Winchester magnum primers.

The primers were flat after firing. I chronographed the load out of my 686+ with a three inch barrel and got 1145 f/s with a SD of 21.81. I did not expect to get flattened primers with the minimum load. The load data shows 1104 out of a six inch barrel.

I loaded up the same round, but with CCI standard primers. I got 1110 f/s with a standard deviation of 17.26. The edges of the primers were rounded, not flattened.

I am puzzled as to why an increase of 35 f/s would require so much more pressure that it flattened the primers. I suspect the Winchester primers are made of softer alloy.

[K-Texas]

I was just testing .357 mag loads this past weekend. I had some accurate #9 sitting on the shelf and I wanted to use it up. I had plenty of odd brass and some Winchester magnum primers. I used the starting load, 11.2 grains under a Hornady 158 gr LSWC, according to loading data:
http://www.accuratepowder.com/wp-conten ... eb-REV.pdf
which lists Winchester magnum primers.

The primers were flat after firing. I chronographed the load out of my 686+ with a three inch barrel and got 1145 f/s with a SD of 21.81. I did not expect to get flattened primers with the minimum load. The load data shows 1104 out of a six inch barrel.

I loaded up the same round, but with CCI standard primers. I got 1110 f/s with a standard deviation of 17.26. The edges of the primers were rounded, not flattened.

I am puzzled as to why an increase of 35 f/s would require so much more pressure that it flattened the primers. I suspect the Winchester primers are made of softer alloy.

Simple: the loads that got the magnum primers were operating at a significantly higher pressure level. A simple test since you have a chrono, use a standard primer and work your loads up in charge-weight until you get the same 1145 FPS you chrono'd for the loads that got magnum primers. Even then, with the same velocity, the loads with standard primers will yield a lower Max Pressure than the loads that got magnum primers.

Much of the problem is data. The older Accurate data that was properly chrono'd from a S&W 6" 686 is the most impressive .357 magnum data in my possession. In BOLD print you'll see it stated that a standard small pistol primer was used for those loads, and that should you use a magnum primer, the charge-weights of the powders in that data should not exceed the START CHARGE!

If you set out to make great loads with AA No 7 or No 9 it will be incumbent upon the handloader to find which powder does best with which primer. So the standard deviation calculator built into better chronographs will help by giving you the standard deviation of either method of using a standard vs a magnum primer. Just remember that with those 2 powders, No 9 might be the better choice for full-power loads while No 7 won't be far behind in velocity, while the better of the 2 for "medium" level target loads will be No 7. Because I've been there, done that, if the goal is target grade accuracy at a higher velocity level than can be had from W231/HP38, well play with as many as you care to. When you get around to True Blue it will speak for itself and I use a CCI550 with True Blue for .357 Magnum loads.

And many who would offer advice might recommend W296/H110/L'il gun. How they fail to comprehend the difference in the internal combustion area of a .357 Mag vs a .44 Mag is a matter I won't waste time on trying to understand. The smaller case capacity of the .357 Mag will not require the powder to burn as slow as what might be ideal for the .44 Mag where W296/H110/l'il Gun are among the very best choices if you don't mind the blast/flash. 11 FS will definitely put an end to that! And back in the day when we didn't have the lot variation issues with Blue Dot, and at a similar burn rate to AA No 7, Blue Dot was capable of giving higher velocity than slower magnum powders like W296/H110/2400, so long as idiot testing wasn't involved, like say publishing velocities where you need to read the fine print that states that they were tested from a 10" barrel.

Another aspect considering burn-rate of powders, the hyper velocity .357 Magnum loads that were chrono'd from a 10" barrel will the poorest choices for barrels shorter than 4". Matching the burn rate proportionately to the barrel length is how I roll in terms of powder selection. And then, powder selection becomes even more finite from that powders pressure stability. The kind of stuff you may not read in a particular handload manual or guide. The odds of getting sound advice on the net . . . it might be best to get some background on the knowledge of the person advising it.

Lastly, flattened primers aren't quite the same kind of evil as poor or difficult extraction from a revolver's cylinder. Thinner chamber walls that come with 7 holes drilled in the cylinder must also be considered. And lastly, the 158 gr. SWC used in the Western Data was hard-cast and not the soft swaged lead of the Hornady bullet which is best avoided for super-sonic velocity or even down to around 900 FPS. And by super-sonic I'm talking about the speed-of-sound at sea-level and approx. 1118 FPS.

[SQLGeek]

Convenience will likely be a factor and you may need to get what's available. Try several and then try True Blue when you run across some. Hopefully you have a chronograph, and one that will give you values for standard deviation.

I don't have a chronograph...yet. It's on the list and it's one of the reasons why I'm not looking to push the envelope on anything. That and I don't want to blow up my Pinned and Recessed S&Ws!

True Blue looks compelling. But small pistol magnum primers being unobtanium right now, I might have to put it on the back burner.

Your BE 86 recommendation looks good. Alliant has data for 9mm in 125 gr LRN which is a bullet I was looking at trying from Brazos Bullet Company. And it just so happens that the 357 data calls for Federal 100 primers, which Midway has in stock along with BE 86.

[K-Texas]

I don't know anyone who shoots full power .357 Magnum loads all the time. As handloaders we tend to experiment with lots of different loads, even the really light Wadcutter loads for target shooting. Follow the data and you'll be fine. With the model 27 and 28 being N-Frame Smith's, I wouldn't be much concerned about wearing them out.

I don't use flake powders because I've just found too many advantages in using sphericals; metering in particular. But in a pinch, or an all I could find kinda situation, BE86 is one I'd want to work with. I haven't taken a hard look at data for it, but from what I've seen, it looks versatile enough, and mid-range loads from the data might be interesting as would loads at or just above start charges. It could be a good choice for someone who doesn't want to stock many powders. Certainly not an issue for me because I have enough sphericals for any load level I choose to make.

Then, because it is flash suppressed, if the need arises you should be able to turn out good defense loads. For very light loads you may find you need something a little faster burning like say, Bullseye. Power Pistol is simply a larger flake cut version of Bullseye to slow the burn rate. Same with BE86 except that a flash suppresant is added, and one reason that BE is in the name BE86.

I might also add that when anyone looks at the Western data you should look at the list of abbreviations for the bullet they used. Page 17 in the downloadable edition No 7 load guide. The good news being that they tend to use more different bullet types than others do.