Flat Primers

[rwsmith]

I don't get it...

This exactly!!!!!! You are pushing the 2400 to at or beyond max loads there.

Alliant shows a max load of 14.8 grains using a Speer 158 grain GDHP. But, if you look on the Nosler website in their load data, they show a max load of 12.3 grains of 2400 with their 158 grain JHP bullet. I am seeing some serious pressure looking at the way the primer extruded out around the circumference of the primer pocket.

BTW, how did these extract from the cylinder? Were they tight or did they come out easily?

I don't understand the 12.3 grains of 2400 as a top load. That to me is a medium load in a .357.

PS: My Lyman book says 14.9 gr 2400 is the max.

 

[99bob]

This exactly!!!!!! You are pushing the 2400 to at or beyond max loads there.

Alliant shows a max load of 14.8 grains using a Speer 158 grain GDHP. But, if you look on the Nosler website in their load data, they show a max load of 12.3 grains of 2400 with their 158 grain JHP bullet. I am seeing some serious pressure looking at the way the primer extruded out around the circumference of the primer pocket.

BTW, how did these extract from the cylinder? Were they tight or did they come out easily?

They came out fairly easy. I've had worse with factory ammo. I didn't have to "pop" them out. Just a simple extraction. I will look into Nosler's info. Thank you for sharing that information.

 

[muddocktor]

Yeah, I know that looking at primers in pistol cartridges isn't the best way to look for pressure signs, but I've also never seen primers extrude around the pockets like that before without also seeing other signs of high pressure, such as sticky extraction. And this isn't just confined to reloads either. Back in the 80's is when I first came across PMC ammo and I remember buying some 357 Mag of theirs that was extremely overpressured. They were extremely hard to extract; had to use my boot heel on the extractor to kick them out of the cylinder on my 27-2 and the primers were as flat as yours, with some extrusion around the primer pocket like yours too (not as much though). That gun isn't cut for moon clips. I was glad it was an N frame 357 with that box of ammo.

 

[99bob]

I don't understand the 12.3 grains of 2400 as a top load. That to me is a medium load in a .357.

PS: My Lyman book says 14.9 gr 2400 is the max.

Regardless. I made a rookie mistake and thought I knew everything. I appreciate the heads up and the great information.

Give me some props for being aware enough to stop shooting them and ask questions. Did you all notice I shot very few out of my box. This was first time out with these loads. One of the first things I do is check for pressure signs and bullet jump. I was second guessing myself, but threw the moon clip in. They are flatter on the moon clip.

 

[99bob]

Yeah, I know that looking at primers in pistol cartridges isn't the best way to look for pressure signs, but I've also never seen primers extrude around the pockets like that before without also seeing other signs of high pressure, such as sticky extraction. And this isn't just confined to reloads either. Back in the 80's is when I first came across PMC ammo and I remember buying some 357 Mag of theirs that was extremely overpressured. They were extremely hard to extract; had to use my boot heel on the extractor to kick them out of the cylinder on my 27-2 and the primers were as flat as yours, with some extrusion around the primer pocket like yours too (not as much though). That gun isn't cut for moon clips. I was glad it was an N frame 357 with that box of ammo.

I can relate. I'm still going to shelf these and start again. Maybe I'll pull them on a rainy day.

 

[oink]

I don't understand the 12.3 grains of 2400 as a top load. That to me is a medium load in a .357.

PS: My Lyman book says 14.9 gr 2400 is the max.

Yeah, my old and newer Lyman books says 14.9 but my Sierra 3rd shows 15.3 and my Speer #10 shows 15.9. However, my Hornady 4th Edition lists a max of only 13.5.

Regardless, the signs reported scare me and that Scandium frame is probably not the best platform for particularly hot loads anyhow. A Super Redhawk might be more appropriate.

 

[muddocktor]

For your information, here is the data Nosler lists for their 158 grain JHP bullet. I took a screen shot of the page for you to look at the data:

 

[Forrest r]

Excellent catch muddocktor!!!

2400 is all over the place in the 357. Lyman 49th has max 14.9gr, speer #12 has max at 12gr and change, hornady has max at 13.5gr.

It's the design of the bullet and how much of that bullet is seated in the case/case volume.

2400 is 1 of those powders that has what's known as diminished return. That's why I like it so much & use it in anything from 38spl's p+ loads to 308w's.

Diminished return and a chronograph:
If you work your 2400 loads up (ladder test in .3gr increments) and shoot them over a chronograph you will see the velocities steadily rise as the powder charge increases.You will get to the point that there will not be as much of an increase in velocity per ladder jump as there was in the beginning of the ladder test. That's called diminished return. No increase in velocity/minor increase in velocity but an increase in pressure.

Typically this is where I stop. No since in increasing pressure with no real gain in velocity. You will find that your sd/es will be at their best also.

FWIW:
I use 14.7gr of 2400 to push a cast 158gr hp in the 357's. Most of that bullet is outside the case/in the huge hp of the bullet. I could go up to 15.3gr of 2400 for a max load. But when I did the ladder tests with that 2400/cast bullet I found that after 14.7gr there wasn't much return velocity wise. Just more pressure.

 

[99bob]

Excellent catch muddocktor!!!

2400 is all over the place in the 357. Lyman 49th has max 14.9gr, speer #12 has max at 12gr and change, hornady has max at 13.5gr.

It's the design of the bullet and how much of that bullet is seated in the case/case volume.

2400 is 1 of those powders that has what's known as diminished return. That's why I like it so much & use it in anything from 38spl's p+ loads to 308w's.

Diminished return and a chronograph:
If you work your 2400 loads up (ladder test in .3gr increments) and shoot them over a chronograph you will see the velocities steadily rise as the powder charge increases.You will get to the point that there will not be as much of an increase in velocity per ladder jump as there was in the beginning of the ladder test. That's called diminished return. No increase in velocity/minor increase in velocity but an increase in pressure.

Typically this is where I stop. No since in increasing pressure with no real gain in velocity. You will find that your sd/es will be at their best also.

FWIW:
I use 14.7gr of 2400 to push a cast 158gr hp in the 357's. Most of that bullet is outside the case/in the huge hp of the bullet. I could go up to 15.3gr of 2400 for a max load. But when I did the ladder tests with that 2400/cast bullet I found that after 14.7gr there wasn't much return velocity wise. Just more pressure.

Great information. Explains how I tripped and fell on this. I assumed. I'm just glad I was paying attention. I wish I was paying more attention while gathering my load data.

 

[Bakebfr480]

Doesn't look abnormal to me.

 

[ArchAngelCD]

Like I said in my first post, primers are not a good indicator of high pressure in handgun ammo, especially since the OP is Bellingham there was no sticky extraction.

I can tell you, when I was shooting factory ammo all the 158gr Winchester .357 Magnum ammo I shot had primers which were flatter than those. If the only indicator you are seeing are the flattened primers I wouldn't worry.I

Edit:
Here are some new max book loads with 2400
Speer #15
158gr Speer GDHP 14.8gr @ 1265 fps 10" barrel
Hornady #10
158gr Hornady XTP 14.3gr @ 1200 fps 10.5" barrel
Nosler #8
158gr Nosler JHP 12.3gr @ 1520 fps 8.3" barrel ( I DON'T SEE HOW THIS VELOCITY IS POSSIBLE)
Lyman #50
158gr Hornady JHP 14.9gr @ 1279 fps 4" barrel
Alliant Online Data
158gr Speer GDHP 14.8gr @ 1265 fps 10" barrel

It looks like all the sources but Nosler agree on the max charge and velocities with a 158gr jacketed bullet and 2400. Older sources have even higher charge weights. I would say 14.8/14.9gr is a safe and charge especially since that's what the powder manufacture is telling us.

 

[oink]

I can tell you, when I was shooting factory ammo all the 158gr Winchester .357 Magnum ammo I shot had primers which were flatter than those.

I respectfully call BS on that.
I have shot many factory .357s most of which were 158 GR. at many qualifications. Being a scrounger reloader I scrounged the brass I shot and that of many others, used it for years and still have it. I've never seen a primer as flat as the example he pulled. I think the flattest primers I remember were from some Geco brand I bought many years ago, but they weren't anything like as flat as the OP's.

Otherwise I don't claim expert status and the rounds in question may be just fine. But they would scare the **** out of me.

 

[ArchAngelCD]

Why in the world would I say that unless that's what I have seen? I also specifically said 158gr Winchester ammo, not all 158gr ammo. There was nothing respectful in what you said.

 

[oink]

I'm sorry if I offended you. That was not my intent and I should have been more diplomatic in expressing my disagreement.

Furthermore, out of curiosity I went and looked in my storage closet. I saved many of the boxes the Dept. ammo came in and put my reloads back in the boxes. Most of the boxes are Win. 145 GR Silvertip. There is some Win 158 GR but most of the boxes are the 145 Silvertip, so I can't confirm my previous statement.

They currently contain 160 GR gas checked cast lead (wheel weights) SWC on top of 6.5 GR of 231 and probably CCI Mag primers but I didn't mark the primers on the box. Looks like about 8 boxes still loaded. I think I need to go shoot the new (to me) 6" 19 I bought at the LGS a couple of weeks ago.

 

[Paul105]

Primers are not necessarily indicators of excessive pressure unless totally "Nailed" or blown primer pockets, and "nailed could be excessive head space.

OPs orig pictures ARE NOT FLAT flat primers.

15.0gr of 2400 under a 158gr bullet (unless a full wadcutter or maybe w/mag primer) is not going to be a problem in any .357 Magnum rated revolver.

Nosler manual for handgun ammo is an outlier -- if you don't believe, compare .44 Mag and .454 Casul to other manuals.

FWIW,

Paul

 

[Misskimo]

My 460 primers are almost alway flat. If the cases come out . U good .
also My factory 300 Ultramag Rimington shells are flat. But not as flat as the 460

 

[robert1804]

What does an obvious pressure warning sign look like?

The pressure warning I use in a S&W revolver is difficult extraction. I consider that the first and final warning. The only reliable visible sign is a kaboomed revolver. Rugers have a flat area around the firing pin so you can see a really flattened primer. Excessive case head and primer pocket expansion are good pressure indicators but aren't really visible. Sticky extraction happens before this in my experience.

 

[27 Man]

I have shot a Lyman 358156 with a gas check and 15 grains of 2400 for years in my model 27 revolvers. Never had an issue with flattened primers or sticky extraction. I did change from magnum primers to standard.

 

[Forrest r]

I have shot a Lyman 358156 with a gas check and 15 grains of 2400 for years in my model 27 revolvers. Never had an issue with flattened primers or sticky extraction. I did change from magnum primers to standard.

Nice!!!
The lyman 44th edition (1967) lists a 5" bbl/max 2400 load 358156 bullet:
15.0gr 1270fps
The lyman 3rd edition cast handbook (1980) lists a 4" bbl/max 2400 load 358156 bullet: 14.0gr 1299fps 41,900 cup
The lyman 49th edition (2008) lists a 4" bbl/max 2400 load 358156 bullet:
14.0gr 1299fps 41,900cup

The lyman 3rd & 49th also list the 358311 160gr bullet with a max load of 15.5gr of 2400 1344fps 39,700cup

The 358311 uses more powder but yet has a lower pressure. Must be a seating depth thing/how much case capacity the bullet takes up.

 

[Forrest r]

Odd
I always thought the 1st sign of over pressure was primer flow where the fp hit.