Questions about. 357 mag reloading data

Use the load data that best matches your bullet. That company has performed tests using that specific bullet and powder combination. Different brands and shapes of bullets will have different effects on pressure. Do any of these sources state the pressure that those given loads will produce? Maximum pressure for .357magnum is 35,000psi (SAAMI). You're doing the right thing by working your load up.

Nothing to worry about having low capacity case fill. I have used .357magnum handloads with as little as 3gr of powder which doesn't even fill the case by 25%. Just be wary of accidentally throwing a double charge because this won't overflow the case.

You may already know from loading .45-70 that you will need to flare the case mouth if you're using lead bullets, otherwise you can crumple the brass or shave lead off the bullet.

Mixed Nuts said:

I
These two sources have data for Accurate No9 and cast .357 magnum bullets.

One book has data for 158 grain cast RN bullets over a max load of 13.7 gr of No9.

The other has 15grs of No.9 as the max for a 160grain cast RN bullet.

And... that same book has 13.5grs of No.9 as a max load for a 168gr LSWC.

So. I loaded 158 LSWC at 12.4, 12.8, 13.2, and 13.4 grains of No.9.

But, after a considerate suggestion, I went to the alliant, western powders load data.

There, a SWC bullet at 158grains, has a max load of 12.4 gr of No.9!

Anybody have any opinion about this? Did I load too hot? Why the wild discrepancies in data between sources?

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It is a common question or "dilemma"

Different tests, different methods different data, time place etc. Different bullet.

When in doubt use the Powder Company data. Even that is a SWC vs your RN but the bullet weight is the same so that's fine.

Consult 3 sources and get 5 answers

#9 Powder is Accurate not Alliant, It is a slow powder so there is more "fudge" room as opposed to fast powders which can make a BIG difference

As you are just beginning I would stay at the 12.4-12.8 range, no need for the higher loads unless you have some need to waste powder or knock down trees or something.

This is a pretty common finding in 357 magnum load data. No two sources ever agree. Some 357 load data such as Lyman's and older Speer data was developed by shooting in an actual 357 magnum revolver, and others were developed in universal test barrels. Data created in an actual revolver is usually substantially higher than test barrel data because the cylinder gap on a revolver bleeds off a lot of pressure which allows a bit more powder to be used before pressure signs are encountered. Speer has stated that some of the data in there older books was developed by just shooting the revolver with different charge weights until extraction became sticky and they called that the max. No pressure measurement devices were used. I have loaded up to many of the loads listed in my lyman book without trouble.

Its pretty easy to tell pressure signs in a 357 revolver. When the primers are flattening out and it takes just a little extra force on the ejector to push the cases out you need to back down half a grain or so.

Another point, Accurate powders are finely granulated and like dust as you noted. Not all handgun powders are that way. In fact some like Alliant Unique are quite course and bulky.

http://www.ilrc.ucf.edu/powders/sample_detail.php?powder_id=17

Study all photos of #9 . Look at the different manufacturers Check chemical in each.

1 photo looks very different then the others.

Note that Olin and IMI is listed as a manufacturer. Blended surplus powders from both??

This may account for the wide range of loading data? Ball powders need a magnum primer or one that is for a 357 mag. Reloading data lists these primers to be used with the 357 magnum. CCI 550 Mag., WSPM, FED 200, REM 5 1/2 .

This reloading sure is fun.

Accurate #5 Walkalongs photo. The burn rate may be close or the same, but doesnt make me want to use any Accurate powders.

Different Powders, same Number. Good reason to start low on the powder charge and work up to maximum, when opening a new can of powder. Accurate's powders have been made different places over the years. Here is a sample of two lots of AA #5. One from the 80's and one from 2006.

Hodgdon has some powders made in different countries, that are listed as the same. IMR 4198 is one. Canada and Australia.

Understandable. I haven't seen the two books you mentioned in a couple decades, didn't even know they were still in use. As noted above it is not common for one manual to have exactly identical data than another manual because of component and testing differences. For load data, where mistakes can be disastrous, I suggest one keep as current as possible, so find a newer published manual, like the Lyman 50th and put the pamphlets and "one caliber" books on the shelf for future entertainment. I would only use online data from powder manufacturers, no forums, and no pet loads websites. I've had zero problems with getting load data from published manuals in over 30 years...

Mixed Nuts said:

One difference, the handgun powder was like dust and the volume of dust per case was smallish. Periodically, I would pour a charged case back into the scale pan to recheck that I wasn't losing powder to static cling or window breeze. Seemed okay.

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Something to keep in mind. Many of our favorite handgun cartridges such as 38 Special, 44 Special, 45 Colt and some others were originally released loaded with black powder. The cases had to be large to get enough powder in the case so that the cartridge performed as desired.

When smokeless powders were developed, they developed lots more energy per unit than black powder so a considerably less amount of powder was needed. Hence, as you are seeing, the 357 Magnum you are loading is not full of powder.

Note, 357 Magnum was never a black powder cartridge, but was an evolution of the 38 Special, which was. So that the 357 Magnum cases would not chamber in a 38 Special gun, they increase the length of the case. The higher pressure capability of the 357 Magnum cartridge allows for a great fill percentage with many powders though.

Cartridges released after the development of smokeless powder such as 9x19 or 45 ACP generally are full of powder as the cases are smaller not needing the volume of powder the old black powder rounds needed.

One safety concern when reloading the cartridges originally developed for use with black powder, the cases will fit double or even triple charges of smokeless powder causing a very high pressure round that will wreck a gun. It is important to double check that cases have not been excessively charged.

On to Accurate powders. Over the years, Accurate powder production has moved around from plant to plant and manufacturer to manufacturer. As a result, the data changes a bit from time to time. Assuming you have current manufacture Accurate powder, I'd recommend using Western Powder's current data.

Here is a link to their current data.

http://www.ramshot.com/wp-content/uploads/2010/09/WesternLoadGuide1-2016_Web-1.pdf

OP, another thing to be aware of when looking at data for lead bullets is the bullet construction (for lack of a better word). Some manuals list data for a swaged bullet vs a hard cast. This will have a difference in charge weights as the pressures needed to move them down the barrel will be different.

My Lyman #49 lists a start of 13 and a max of 14.5 max with a 155 cast and a start of 12.3 and max of 13.7 with a 160 cast.

Shoot what you have, at 11.4 to 12.2 grains it should still be pretty mild. If you can still push the cases out of the with a finger on the ejector you are okay. I would not be worried at all to work up to 13 grains in .3 grain steps while keeping an eye on the primers and paying careful attention to how the brass extracts. If the brass starts to take more than light finger pressure to extract back up a bit. If you have a chronograph that can be useful as well.

LYMAN cast manual lists a 160 gr hard cast RN bullet loaded 12.3 to a max of 13.7 gr of AA#9

The difference between a 158 and 160 is nothing, In fact one can use the data for the next HIGHER bullet weight.

It is pretty hard to blow up a revolver using SLOW powders, depending on what gun you are shooting out of??

If you plan on pulling then pull the highest loaded ones (you have them labeled right??)

Probably can get away with them in a Ruger, but hey, why risk it?

Mixed Nuts said:

Someguy2800, gonna do more loading before shooting. Will walk it up toward 13, or 13+. And if I get a great load in the high 11 or low 12 gr range I may stop there.

Rule3, . Yes my friend, I know which are which. I'm not that sloppy.

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Sorry about that, I was working on a 2400 powder question also.

I went back and edited my reply to indicate AA #9

"...very different than the 45-70..." Just because of the relative sizes of the components. Mind you, other than some of the magnum rifle cartridges, everything is smaller.
"...load data that seems to contradict..." Nature of the beast. Some on-line data is newer. Some is the same as the book data. All manuals will be slightly different as they reflect the conditions and exact components used on the test day only. Primary difference is the velocities. That's caused by the slight differences in powder lot burn rates. However, there's an issue with some on-line sites using magnum primers for magnum named cartridges with some powders and not in cartridges that are not magnum named. Isn't terribly important, but it's wrong just the same. Pressures might be different.
"...Ball powders need a magnum primer or one that is for a .357 Mag..." Not at all true. Magnum primers are about how easily the powder used ignites and nothing else. Absolutely nothing whatever to do with the cartridge name. The one used for a .357 Mag is a small pistol primer. Not a small pistol magnum primer. Period.
"...and cast .357 Magnum bullets..." The important part of that is the 'cast' part. Cast and jacketed use different data. You cannot drive a cast bullet at the same velocities as a jacketed bullet without causing leading in the barrel. And the hardness of a cast bullet makes no difference. A plated bullet is not a jacketed bullet either. They use cast data.
Anyway, as long as your loads are within the ranges in whatever manual you use, you're safe. Old manuals and pamphlets included.

OP, IIRC Swaged lead bullets will work in lower pressures and velocities so will generally call for smaller charges. Cast, as they are harder will require more pressure to get moving down a barrel.

Another thing to consider as you look at data - be aware that some companies, Alliant for example, may only publish the max load. This is sometimes apparent in some data where you will only see one number listed, and hopefully a note somewhere on the page that indicates it's a max load and to reduce by 10% (commonly) for starting loads.

And another point is that the bullet styles, bearing surface, etc, will yield different results.

The other consideration is that the newer editions of many reloading manuals have reduced the max load information. In some cases this may be due to lawyer influences and in others due to better refined pressure testing that has led to a greater understanding of the pressures as measured with more modern devices as compared to the pressure cup crush method.

And the last thing to mention is that some of the one caliber books I have seen have been reprints of older data in one small book. I don't know if that's the case in the book you referenced above. But, since you are using a certain powder a good starting point would be the powder company's data, which you are referencing.

The only thing I'll add to this is that many many people have been shooting the loads listed in these books for decades without issue. With modern pressure equipment some of the old load sources have been found to be over saami pressure, none the less those loads were not blowing up guns. Though I think they should have stupid tatoo'd on there head, I've seen people shooting loads that had to be pushed out of the cylinders by pushing the ejector against a table and claimed to have been doing so for years. Those are the kind of people that blow up guns. I once had a load within book maximum where I had to do that, but one cylinder was enough of that! When I'm working with a 357, if the brass falls out I know the pressure is modest. Once the brass is totally filling out the cylinder but is still not taking more than a couple ounces to eject I know I'm where I want to be. The most important thing is to listen to what your gun is telling you, and a 357 revolver is very good about telling you when enough is enough. Your security 6 is a good strong gun.