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357 AMP handloading

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paul v. View Drop Down
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    Posted: 14 Jan 2019 at 6:40am
This may help.
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Luc V. View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Luc V. Quote  Post ReplyReply Direct Link To This Post Posted: 12 Jan 2019 at 11:36am

Luv2shoot,

The numbers on the supervel file are CUP (copper units pressure) to make it even more difficult there is also LUP (Lead units pressure). Those two terms were used back in the days, depending on the type of crushers used.

One remark about the conversion formule you found, I would not trust this much because there are to much different copper crushers used. With each new batch of proofed crushers you had to be recalculate the whole formule to get the correct pressure. Back then you could not just read the pressure from a clock on the test pressuregun. It had to be calculated from the measurements of the crushed piece of copper.

 

As far as your 19 grains of H110 it might work well. The reason the slow powders work OK on much lighter loads as usual is because you used it in a bottle necked case instead of a straightwall case. I'm pretty sure  a to light load would not work well in a straightwall case.

I have a similar result with my 357 Sig caliber.

Because you have to push all that volume of burning powder throug a smaller diameter the pressure will rise (due to the shoulder in the shell) before the bullet leave the shell, not the barrel. Difficult to explain in words, but try this to understand: take a waterhose and sqeeze it off to a smaller diameter you will see that it will spray water much further because of the rised pressure. If you sqeeze it even more tighter you might burst the hose (if enough water pressure to start with.) I hope this makes you understand somehow the way pressure works...

 

To get back to your 19 grains load, to make it work well and consistent, make sure you have a verry good grip of the bullet in the case. The use of a factory crimp die (I use Lee Presicion) is recomended. If the bullet has to little grip in the case the primer can have enough force to push the bullet foreward before a good ignition of the powder. Then you should find much unburned powder in the barrel. If it burn well and have a clean barrel, you a probably good to go. 

About a case not completely filled with slow burning powder, it fails because there is to much room (airspace) inside the case and primer has enough force to blow the powder foreward and the flame is to cold to short for good ignition. I doubt it it could happen in a 357AMP case with 19 grains H110. Thats why I said to use magnum primers.

In all my reloading experiments I had that happen once with a very light load in 45-70 Gvt cartridge. I worked well when I switched to magnum primers.

It all sound difficult, but its just logic....

 

 

 

 

 

 

 

I would suggest to load 20 or 30 rounds and try them but also look good for accuracy, if they are consistent and good groups, it will work fine. If you have fliers all over the target the pressure (ignition) is not reliable you should adjust the load.

 

 

 

 

 

 

 

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Post Options Post Options   Thanks (0) Thanks(0)   Quote BEEMER1 Quote  Post ReplyReply Direct Link To This Post Posted: 12 Jan 2019 at 12:33am
As far as 19 grains being as low as one should I guess that all depends on the gun.  I was told to start there and work up until I found a load that would lock the bolt back and met my accuracy expectations.  Both 19 and 20 did that in my gun so I stayed at 19.

The springs in my gun probably need changed and after putting in Wolff +10% springs I am sure I would need to go up.

good luck.


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Post Options Post Options   Thanks (0) Thanks(0)   Quote Luvz2Shoot Quote  Post ReplyReply Direct Link To This Post Posted: 11 Jan 2019 at 9:11pm

Beemer:  About 15 years ago, not too long after I got my first 357AMP, I was at a gun show and on one of the tables a guy had a small plastic bag with shells in it.  Written on the bag was "40CT.  357 Auto Mag. $5".  Needless to say I couldn't get a $5 dollar bill out of my pocket fast enough.  When I got home I checked each shell in my gun.  Each shell allowed the bolt to close and rotate into the locked position.  Right then I knew I got lucky running across these.

Starting this reloading process I started with a different 357 barrel but used those shells as a starting point.  I locked the bolt open and dropped a shell into the chamber.  Very slowly I closed the bolt and it only "hung up" when the extractor went over the rim of the shell.  Once the shell was against the bolt face I closed it all the way and it rotated and locked into place.  I knew that those shells would give me a good starting point at seating the shoulder depth.
 
I set the shell in my 357 necking die and ran the die down to the point that it just touched the shoulder.  I backed the die off about 1/2 of a turn.  I ran the first 44AMP shell into the neck die.  I then put it in the gun to see if the bolt would close and lock into place.  (the first time did not).  Then I turned the die down a little and ran the shell again to neck it just a little further.  Again, I checked for fit.  After about 4 or 5 minor turns of the die I got the neck down far enough to fit into my chamber - but it was tight!  So, I took the die and turned it down a hair more.  The shell dropped in and the bolt was able to close and rotate into the locked position.
 
I then did the "test" that Tim Bell posted in another thread.  With shell in the barrel and the bolt close and locked on it, take the end of the barrel and push it into a towel and watch the travel.  I observed how far the barrel moved before the bolt started to unlock and rotate.  I guessed that with very little "play" before the bolt started to disengage, I got the shell to rest on the bolt face where it is supposed to, and that I had gotten the shoulder fit for my gun correct.
 
I ran a bunch of 44 shells to that neck depth.  I verified that each shell dropped in and checked the "barrel push check" on every shell.  I was assuming that I got everything correct every step BEFORE loading with any powder.
 
Before dropping powder into the first shell I had read everything that I could.  I must have put a good 10-15 hours into reading, searching, and posting on here.  This has been fun and I can't wait to start loading a few hundred rounds for the 158gr bullets.  THEN I'll start to work on some hole-punching loads for the 125gr bullets.  I plan to start at Lee's lowest suggested load (LOL).  And I will go back through and see what other "recipes" people have shared for the 125gr bullets.
 
Luc:  Thank you for posting this.  I noticed they are testing 24gr of 296.  WOW!  In the "pressure" column, do you think that is PSI or CUP pressures?
 
I found this conversion online:
 
CUP to PSI:
(PSI + 17902)/1.516 = CUP
 
PSI to CUP:
(1.516 x CUP) - 17902 = PSI
 
 
By your numbers (above) that you got from your program, I am only right around 24569 CUP.
 
(19345 + 17902) / 1.516 = 24569.
 
 
As Beemer and you have mentioned/hinted, for this gun 19gr of H110 (or W296) should be right around the very lightest we should be using?
 
 
If you were happy and you knew it, would you clap your hands?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Luc V. Quote  Post ReplyReply Direct Link To This Post Posted: 11 Jan 2019 at 5:09pm
If I remember well, I have an email from the late Lee where we discussed pressure in automag cartridges and he said that he usually worked around the maximum of 50.000 CUPs. for the 44
I guess the 357 should be much the same.
Included is an old file about tests he did for the 357.
 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote BEEMER1 Quote  Post ReplyReply Direct Link To This Post Posted: 11 Jan 2019 at 2:54pm
Originally posted by Luc V. Luc V. wrote:

To Luv2shoot, it's easy to know the volume of the resized case, just pour water in the case and fill it to the top. That weight in grains is the maximum volume.
 
To beemer, I'm almost sure Lee Jurras never tested the Automag cartridges in PSI. Back then all testing was done in CUP. There is a Huge difference between the two.
It's a mistake often made to mix those numbers/parameters.
 

Luc, you  are probably right and I was aware of that when I posted the comment.  I do not remember if I read that or Lee told me that and I do not know where to look for it.

All I know is that Jurras tested some Lomont AMP loads and the were well into pressures that are normally only seen in magnum rifles.  Jurras said they were well beyond anything he would load.

Luv2shoot  -  I understand your concerns.  I will say this, after 30+ years of hand loading I could not come up with a worse cartridge to start on than the 357 AMP.  With head spacing concerns, reformed brass, and user unfriendly powders it is a tough one for anyone.

When I bought my first 357 AMP it came from a girl and it included 2 boxes of ammo from a commercial reloader.  There were only two rounds fired out of the 40 which I found strange.  

I loaded one round and fired it and everything went fine.  I loaded two rounds next and the gun would not fire as it was not in battery.  I started checking the ammo and nearly all had the shoulder too far forward to chamber.  I checked my gun against the dies and the headspace on my pistol was out of spec and I had to remove material from the bottom of the die to reload for it.

When loading for Auto Mags caution is advised.
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Luc V. View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Luc V. Quote  Post ReplyReply Direct Link To This Post Posted: 11 Jan 2019 at 2:39pm
To Luv2shoot, it's easy to know the volume of the resized case, just pour water in the case and fill it to the top. That weight in grains is the maximum volume.
 
To beemer, I'm almost sure Lee Jurras never tested the Automag cartridges in PSI. Back then all testing was done in CUP. There is a Huge difference between the two.
It's a mistake often made to mix those numbers/parameters.
 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote BEEMER1 Quote  Post ReplyReply Direct Link To This Post Posted: 11 Jan 2019 at 3:28am
Originally posted by Luvz2Shoot Luvz2Shoot wrote:

Luc,

Thank you for the info and the offer. I am not an experienced loader either. In fact this was the first time that I have loaded for anything. I figured that if I can meticulously go through the process to load my 357AMP, I can apply it to just bout anything else that I shoot (and feel fairly comfortable doing so).

I do have to say that after firing off the 19gr load and seeing what the gun did, I just can't imagine loading it any higher. After reading everyone's input, I see that it can go higher.

Thank you for running the info through your program. I have no idea what the volume of the case is, but I can see what I can find. I am trying to load these things exactly as published by Lee and other sources. I am loading with CCI 350 Magnum pistol primers. (I do remember reading to only use magnum primers when loading for these.)

Does anyone know what sort of pressures these things can be loaded up to? I thought i remember reading that Lee and Kent were testing/shooting these pushing 30,000 CUP?



Lee Jurras tested some of Kent Lomont's loads in his pressure barrels at Super Vel and he had loads for the 44 and 357 AMP at 65,000 psi.  Glad it was not me or my gun doing the shooting.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Luvz2Shoot Quote  Post ReplyReply Direct Link To This Post Posted: 10 Jan 2019 at 11:56pm
Luc,

Thank you for the info and the offer. I am not an experienced loader either. In fact this was the first time that I have loaded for anything. I figured that if I can meticulously go through the process to load my 357AMP, I can apply it to just bout anything else that I shoot (and feel fairly comfortable doing so).

I do have to say that after firing off the 19gr load and seeing what the gun did, I just can't imagine loading it any higher. After reading everyone's input, I see that it can go higher.

Thank you for running the info through your program. I have no idea what the volume of the case is, but I can see what I can find. I am trying to load these things exactly as published by Lee and other sources. I am loading with CCI 350 Magnum pistol primers. (I do remember reading to only use magnum primers when loading for these.)

Does anyone know what sort of pressures these things can be loaded up to? I thought i remember reading that Lee and Kent were testing/shooting these pushing 30,000 CUP?


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Luc V. View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Luc V. Quote  Post ReplyReply Direct Link To This Post Posted: 10 Jan 2019 at 5:50pm
Luv2shoot,

First I want to say I do not reload the 357 AMP cartridge but out of curiousity
I just ran your loading data through the QuickLoad program and it gives the following result:
Velocity 1218 fps (for a 6 inch barrel)
Chamber pressure 19345 psi
Case filling = 71.4 %
Amount of burned powder when bullet leaves barrel = 69.25 %

If you interested in a full ballistic result for your exact cartridge, send me an email and I return with a screenshot from my computer with full details.

For a correct result I need the grains of water (volume) from your resized 357AMP case, the OAL of the complete cartridge, the load of powder and the type and weight of the bullet. Also the barrel length of your gun.
When I have that I can send the you data for your gun/cartridge.

So far I see it's a fairly low load.

Just one remark about slow burning powders and light loads, be sure to use MAGNUM primers.

The magnum primers make all the different in ignition. Magnum primers have a longer and much hotter flame as others. Just shoot a primed case with the different primers in low light and watch the length of the flame.

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