AA#7 357 loads

[Spawndn72]

I am confused.

For a 158 grain lead SWC Accurate shows a starting load of 9.1g and a max of 10.1 as follows
"158 (L) LC SWC 9.1 1,041 / 10.1 1,183 33,228 1.580"

Lyman 49th edition shows doesn't have a 158 grain, but it goes have a 155 grain which I would think would at least be close, but it shows:

"155 (L) SWC 10.8 893 28,300 / 12.0 1146 41,300"

How in the world can the be that far apart?

 

[rockquarry]

Different pressure guns, perhaps different dimensions, different operators, different bullets with different bearing lengths, different powder lots, different primers, different seating depths, different brass, maybe some other factors... I don't think this is all that unusual. A good reason to have a variety of load manuals for comparison.

 

[Nevada Ed]

A actual weapon or a Universal Receiver can make all the difference in the world.
Plus the type of bullets make up, OAL and chamber fit will toss in a monkey wrench.

When in doubt.........
I go with the powder companies data, and build from there.

Stay safe.

 

[rwsmith]

I'm an old reloader.....

... and have learned that their are substantial differences between load data from different sources.

HOWEVER, sometimes I see something that is mind boggling and that is one of them.

Another thing that bugs me is that my longest pistol barrel is 6" long and my shortest rifle is 16" long, while the universal receive is 10". It looks like one those thing that doesn't correlate with anything in the real world in order to keep people from making assumptions.

 

[stansdds]

Different manuals can give wildly different load data. I tend to look at all of my manuals and consult any information available from the powder manufacturer. I tend to look at all my data sources and try to find some common ground.

There will be tons of variances depending upon weapon, brass, primer, bullet, and seating depth of that bullet, and even case mouth crimp. This is why it is best to start with the starting load and work up. Never start at or very near the top.

 

[gwpercle]

I am confused.

For a 158 grain lead SWC Accurate shows a starting load of 9.1g and a max of 10.1 as follows
"158 (L) LC SWC 9.1 1,041 / 10.1 1,183 33,228 1.580"

Lyman 49th edition shows doesn't have a 158 grain, but it goes have a 155 grain which I would think would at least be close, but it shows:

"155 (L) SWC 10.8 893 28,300 / 12.0 1146 41,300"

How in the world can the be that far apart?

I have noticed the discrepancies since 1967....and after 50 years there are still discrepancies but there are just so many variables..
One of the reasons Lyman's might be different is the bullet they used. the 155 gr. SWC #358156 is cast of hard Linotype (BH hardness 22 to 24)and fitted with a Gas Check . The accurate bullet is a Laser Cast lead , bevel based (no gas check) bullet , according to their site BH hardness is 24.
So although the bullets are quite similar...that little copper cup on the base of the Lyman allows it to be loaded to a bit higher velocity. The plain bevel base of the laser cast is a minor difference but could explain the discrepancies....

Then again...I could be totally wrong...maybe the guys at Lyman are just more "adventurous" in their testing ????

I cast and load the #358156 in 357 magnum with accurate #5 and have not found Lyman's data to be excessive with this bullet, hard cast and gas checked.
I would use Accurate data with softer cast plain or bevel based bullets.
About all we can do is pay attention to the variables , use the data that fits the components we are using and use some good old fashioned common sense.
The little details can and do matter...sometimes a lot so pay attention to the details.
Gary

 

[Mark in GA]

The most obvious answer here is one I have run into more than a few times with 357 Mag. We all know there are two pressure measuring systems, PSI and the older Copper Units (CUP) system. With these two systems applied to 357 there is quite a difference in the two limits. 35,000 PSI on the newer true PSI system and 45,000 CUP on the old. You can’t always make this statement because the systems vary from cartridge to cartridge and there is no real mathematical formula to convert from one system to the other. But in 357 Mag one thing that can be said for sure is when the CUP pressure system and limits are used in the testing, the result is much stronger/hotter/powerful loads. You can even see it across the load data that Accurate themselves have published over the years as they started with 357 in PSI, then for a few years used the CUP limit since other powder manufacturers powders/loads showed greater performance (using the CUP system) they switch their 357 loads to CUP testing. Now they are back to PSI and the lower load limits.

Mark in GA

 

[Spawndn72]

Thanks for the explanations everyone. I am using xtreme bullets 158 grain SWC with a Brinell of 18 with 9.4 grains of AA#7. They are pretty light but shoot great. This is my first time reloading 357.

 

[mtgianni]

A few decades ago Accurate told everyone to please junk their loading manual #1 and not to use the data. No matter the source make sure it is current or safe with your lot of powder.

 

[S&WIowegan]

Old data is NOT necessarily appropriate for modern powder, primers and guns. One reason is powder mills sometimes blow-up and never get rebuilt. When I first started using AA#7 in the early 90s, the powder was made in Israel. Then Kaboom and the powder was next made in Czech Republic. I don't now where it's made today. This one reason older data is suspect. Another reason is better technology today gives more reliable data.

 

[JagmanFL]

I've learned the hard way to not stick with one publication, or even two. I too use Accurate Powders. I load for my .357 J-frame. I wanted to try some #9 powder for the first time. Western Powders says the start load for 158 Hornady XTP at 1200 fps is 12.4grs. Lyman Load Data starts at 13.4 grs for the same load. I loaded 20 rounds as an experiment at 12.4 grs. Thinking it was the safer load. I went to the range, and KABOOM. Damn near blew the gun out of my hand with a huge explosion. I have a bag with the remaining rounds to this day, dated April 2016. I have since got the Hornady 10th edition reloading book. It says to start their 158 XTP rounds at 9.7 grs, at 1000 fps. Their top load is 11.5 grs at 1200 fps. I'm now loading them at 9.7 grs of #9 and they shoot much easier. Over the years, I've learned to use many different manuals. Then again, after so many years, I've created my own set of notes on which powders to use on which rounds. As you move forward in this hobby. Take good notes on everything. Powder, load, bullet. You'll soon have your own set of notes to rely on.

 

[rockquarry]

I have about fifty load manuals going back to the '50s. Much of the old data is comparable to current data, some of it isn't. I use current data, but the old books are invaluable as reference sources.

A lot of the old loads were never pressure tested. Empty cases were eyeballed for high pressure signs. I have the original Accurate Arms book as well. It does have a hot load or two, but probably not as many as some think.

 

[shocker]

I've learned the hard way to not stick with one publication, or even two. I too use Accurate Powders. I load for my .357 J-frame. I wanted to try some #9 powder for the first time. Western Powders says the start load for 158 Hornady XTP at 1200 fps is 12.4grs. Lyman Load Data starts at 13.4 grs for the same load. I loaded 20 rounds as an experiment at 12.4 grs. Thinking it was the safer load. I went to the range, and KABOOM. Damn near blew the gun out of my hand with a huge explosion.

Are you saying the loads aren't SAAMI compliant or that shooting 357 MAGNUM from a pocket pistol is a bad idea?

 

[JagmanFL]

I'm just stating facts from personal experience. Using the publications that I had access to. Loading for my personal firearm. I'm certainly not accusing any publication of being wrong. I'm sure someone loaded those loads with their particular firearm and gathered the data. I was just saying to use a multiple of different publications, and from those you will dial in what is right for you and the particular firearm being used.

 

[rwsmith]

I'm not even sure that the copper pellet...

I'm not even sure that the copper pellet measured peak pressure but more of a total load, which without a clocked curve is pretty useless. One thing I can say is that even with old data I've never damaged anything and I don't know anybody that did that couldn't be pinned most likely on error. I think that the phrase 'strong modern gun' counts for something.

 

[S&WIowegan]

Using the word "KABOOM" usually means to experienced shooters that the gun was destroyed. As best I can tell from your post that's not what happened. Do you mean the load was producing heavy recoil? You might be surprised that some people are less recoil sensitive than others. Also shooters can learn to handle recoil better. The first time I fired a 44 Magnum I used factory ammo in a Ruger Super Blackhawk and I was stunned! I eventually got used to the recoil and also got better at managing it.

I had a similar experience when I first shot my S&W 500 magnum. I'm not sure I'm used to it yet.

 

[Old 44 Guy]

It was much easier in the old days when all we had was Bullseye & 2400. Now with new powders, etc. I mainly stick to the old loads my Lyman # 39 book says. My old .44 loads, not Elmer's assure me of sure accuracy.

 

[JagmanFL]

Okay, Kaboom was a bit extreme. No, the gun was not destroyed. But, being a J-frame. What some would call a pocket pistol. I was very uncomfortable with that particular load in that gun. The recoil was very excessive. I could have adapted to it, but I was more concerned for the gun itself. I just felt that load was too hot for that gun.

 

[Green Frog]

My basic rule of thumb is that if I find one source with a load suggestion significantly higher than others, I. Am very skeptical and hesitant to use it... if on the other hand one source is lower than all its neighbors, I’m not as worried about going high with the majority. Theexceptiontothis rule is if I see a downward trend in newer sources, I watch them and act accordingly.

Froggie

 

[stansdds]

My basic rule of thumb is that if I find one source with a load suggestion significantly higher than others, I. Am very skeptical and hesitant to use it... if on the other hand one source is lower than all its neighbors, I’m not as worried about going high with the majority. Theexceptiontothis rule is if I see a downward trend in newer sources, I watch them and act accordingly.

Froggie

And a good rule of thumb I believe that to be.