357 MAG problem

[P5 Guy]

I tried the Nosler 6 recipe for 158gr 357s and got flat primers. Every component was used that the Nosler 6 spelled out. Nosler Sporting Handgun 158gr JHP, WSPM primer, Federal 357 Magnum brass and the starting load of 15.0gr of H110.
I used my new RCBS powder dispenser for every loaded carteridge. When I saw the flat primers I checked the dispenser against my other scale and found they both are in agreement.
Is there a lower starting charge for H110 that works with the 158gr JHPs I have?
I'm shooting these rounds in my GP100 with a 4 inch barrel if that should matter.
Thanks P5

 

[zxcvbob]

I believe flat primers is normal in a revolver. I also believe that 15 grains of H110 is already on the low side. Try going *up* a little.

 

[ArchAngelCD]

Hodgdon recommends a starting charge of 15.0gr H110 with a 158gr Jacketed bullet and a Max charge of 16.7gr. A charge of 15gr is on the low side, I use a charge of 16.4gr with great success. All the primers on my .357 Magnum rounds look flat when fired in a 4" M686, it's normal. Buy a box of Winchester or Remington 158gr .357 Magnum ammo and you will see the same "flattening" on the primers. Like zxcvbob said, it's normal. Bump the charge up a little and you will get better results.

 

[Ben Shepherd]

Yeah, 15 is usually on the low side with a 158 and that powder. You're running a magnum. Flattened primers are fairly normal. FLAT primers are a different story.

Would you by chance be using federal primers? If so they're real soft, they almost always flatten slightly no matter what load you're using.

 

[P5 Guy]

Thanks gents,
I was under the impression that flattened primers were a sign of too much powder? They were not too hard to extract, but they didn't fall out.
I found on line in the Hornady site that they start at 12.7 of H110 for their 158gr JHP.
Now I'm really confused.

 

[buck460XVR]

I found on line in the Hornady site that they start at 12.7 of H110 for their 158gr JHP.

...and their max is 15.6 I believe. The new Speer manual lists their starting load for 158s @ 13.9 and maxin' out @ 15.5.

I shoot 158 XTP's over 15 grains of H110 all the time, it is not my hunting load, but it is a nice magnum target load outta my 6" 686.

 

[P5 Guy]

I'm using Winchester's small pistol magnum primers.
How much would the bullet mean to the load recipe, if I was to substitute the Nosler for the Hornady and use the Hornady charge figure?

 

[Remo-99]

yes seems to be normal for 357mag, i recommend avoiding Federal primers for full power loads though. Being a magnum they run fairly high pressures for pistol primers. I made the mistake of using my Federal target load primers in full power loads as i was out of wsp at the time. The result was primers cratering around the firing pin and into firing pin hole (also running a lighter mainspring in 686).
That then resulted with the cylinder being jammed closed and wouldn't rotate either, easy fix with a few light taps with plastic mallet whilst opening the cylinder, but i did not have that with me when i was out shooting.

 

[Mal H]

I was under the impression that flattened primers were a sign of too much powder?

With that caliber, there's flat and then there's really flat.

With the former, you get flattened primers that still have the firing pin indentation and some radius is still visible on the edges.

With the latter, the firing pin indentation is either flattened out or even bulged out where it tried to fill the firing pin hole; the radius has disappeared and the primer is as flat as the remainder of the head, the only difference being the color! I've only gotten those types of flattened primers a few times, but always in firearms that can handle the pressure.

 

[VegasOPM]

.357 mags run at up to 41,000 CUP- that is definitely flattened primer territory- along with some flowing around the firing pin. Fire off a full power factory load and use that as your basis for primer deformation. I use magnum primers when I load hot .357's- they are a little harder.

 

[joneb]

Every component was used that the Nosler 6 spelled out.

Nosler probably didn't use a 4" GP 100 to test that load. I loaded 12.2 thru 12.8gr of AA#9 behind a Nosler 158gr JHP with WSP, at 12.8 I was getting flattend primers and semi-sticky case extraction, at 13.2gr all of these symptoms went away in a old Colt Trooper .357 I would watch for cratered primers, and really sticky shell extraction

 

[Steve C]

In the picture below you will see 3 different .357 mag primers. The case on the left is flattened, the others are normal. So where your primers really flattened like shown or just typical .357 mag fired primers? A picture would be helpful.

 

[ArchAngelCD]

P5 Guy,
H110/W296 powders work best when they almost fill the case. If you charge only 12.7gr H110 in a .357 Magnum case under a 158gr Jacketed bullet you will have a problem. Loading that light with those powders can case a squib or might even separate the jacket from the lead center leaving the jacket in the barrel. That round isn't a problem but firing the next round gets very interesting.

While bullet companies and manuals are very good sources of load data I tend to trust the powder manufacturers more. There is a lot of good data on the Hodgdon Load Data Site. They are listing a starting charge of 15.0gr H110 and a Max charge of 16.7gr H110 under a 158gr Hornady XTP bullet. Like I said above, I get very good accuracy from a charge of 16.4gr. If you are getting good results with a charge of 15.0gr by all means keep using it but whatever you do, please don't load a charge of 12.7gr because IMO that is not a safe load.

I am also using W296, (same powder as H110) a Winchester SPMP along with Hornady 140gr, 158gr and 180gr XTP bullets. Most of my primers look like those in the Winchester case pictured above. That is fine and fairly normal for a .357 Magnum in a revolver...

 

[Ridgerunner665]

All reloading info is not created equal...after a few years of trial and error I have found Sierra to be the best guideline because they do more research than the others.

Here's what my Sierra Edition V book says about the 357 mag with 158 grain JHP's and H110...from a 6 inch barreled Colt MKIII Trooper

Start load: 13.3 grains @ 1,150 fps
14.8 grains @ 1,200 fps
Max load: 16.3 grains @ 1,250 fps

Starline brass
CCI 550 primers
OAL 1.585

Hope that helps...

 

[eclarsen]

P5 Guy says "I found on line in the Hornady site that they start at 12.7 of H110 for their 158gr JHP."

ArchAngelCD says "please don't load a charge of 12.7gr because IMO that is not a safe load."

Confused?

You bet.

I didn't start that low (12.7 grains), but I am still curious about which manual to believe when considering mins and maxs. The top end is just as variable.

Don't have my manuals handy, but is the bottom line that we have to load up to max for our specific revolver to find out what it is...get to the flattened primer on the left of Steve C's picture (post #12) and back off?

 

[rcmodel]

If you don't have to beat the empties out with a stick, you are fine.

SAAMI reduced the maximum pressure allowed for the .357 years ago from 40,000 plus, to 35,000 now in deference to S&W K-Frame damage, and the little J-Frame guns.

Factory .357 loads of 40 - 50 years ago were loaded way hotter then any load you will find in a new loading manual or factory box today.

Don't sweat the primers.
Load up until you start getting stiff extraction and stop or back off slightly, and you will be fine.

rcmodel

 

[The Bushmaster]

Flattened (and I don't care how flattened) is NOT a sign of over pressure. Cratered, punctured (blown) or leakage around the primer are signs of over pressure as far as primers are concerned. With a revolver the first sign of over pressure is hard extraction as rcmodel discribed.

 

[P5 Guy]

Steve C, They are definitely like the one on the left. When I de-capped them the primers looked like little hats. They had no radius at all. The cup was flared out to the edge of the primer pocket and overlapping the case head a little bit.

 

[buck460XVR]

from last weekend.....we shot a coupla hundred of em at bowlin' pins and clay pigeons. 15 grns of 110 under a 158 xtpHP.....CCI 550 primers. Again makes for a nice magnum practice round that aint hard on the hand or the gun.....with a little more umph than what my son calls the "#ussy rounds". My 686 seems to prefer Lil' Gun when pushin' the 158s real hard.

 

[ArchAngelCD]

buck460XVR,
If you are shooting at full size bowling pins and want something a little heavier for your Magnum try a 180gr Jacketed bullet over 15.0gr Lil'Gun. That load will leave no pins standing and that's no lie!!

Also, I completely agree with what rcmodel said. The loading data and .357 Magnum factory ammo available today is closer to the hot .38 Special ammo available 30+ years ago than true .357 Magnum ammo.