Flat Primers

[99bob]

I've seen flat primers, but the ones in the moon clip seem to be flater. Same batch as the top row in my box.

Nosler .357, 158 grain JHP, p/n 44841
Top row and moon clip loaded with 2400 @ 14.8 grains.

Model two rows are factory Blazer Brass 158 JHP and PMC 158 JLT for comparison.

Bottom rows are the same bullet with H110 @ 15.1 grains.

Has anyone else noted anything like this before? Should I be concerned? I double checked and these are starting loads. I crimped at the cannelure. OAL is 1.580. Good roll crimp.

Firearm is a 327 TRR8

 

[ArchAngelCD]

Primers are not a good indication of excellence pressure in handgun cartridges unless they are really bad.

Those don't look all that bad to me but what do I know?

 

[99bob]

I pulled the primer that seemed to be the flatest. I personally haven't seen one like this before. Funny, my 180 grain loads aren't as flat. I(being a novice) assumed they would experience more pressure.

 

[oink]

Those do look pretty flat to me. Are they getting cratered around the firing pin too? I have no experience with 357s with moon clips or moon clips period for that matter.

 

[oink]

I pulled the primer that seemed to be the flatest. I personally haven't seen one like this before. Funny, my 180 grain loads aren't as flat. I(being a novice) assumed they would experience more pressure.

Hey, I don't claim expert status but that primer doesn't look good to me.

 

[99bob]

Yes there is a slight ridge around the outside diameter of the firing pin impression. More so on the moon clip ones. There is only two that are flat as the picture I just shared.

 

[Ole Joe Clark]

How does the load you are using stack up against what your loading manual says?

Have a blessed day,

Leon

 

[99bob]

Crater picture added.

 

[99bob]

How does the load you are using stack up against what your loading manual says?

Have a blessed day,

Leon

They are starting loads. Powder measured by a PACT digital scale that I calibrate with every use. I also use check weights. Primers are Winchester Magnum Primers. All case we're trimmed to match and all primer pockets cleaned. I was very cautious with these loads as it has been a while since I loaded magnums. It's been years since I loaded a .41 Magnum. I usually do all my .45acp and .38 special, but admit I'm not as picky on those.

 

[arjay]

Look pretty flat from here.How was the recoil compared to a factory load?

 

[99bob]

Look pretty flat from here.How was the recoil compared to a factory load?

Recoil was manageable, maybe 7-8 on a 1-10 scale. Factory stuff being a 6-7. Seems liked the PMC was a little more noticeable than Blazer Brass. Likewise my load was a little more noticeable than the PMC. The 2400 was a little louder than the H110. I was expecting it to be the other way around.

 

[oink]

I gotta say something isn't right. I've never had a primer that flat. I'd start over from scratch starting with the loading manual data, weighed loads. You didn't empty a powder reservoir into the wrong can of powder by chance? Again, I'm no expert but those primers would scare me. How do the cases look? Are they getting bulges near the base?

 

[robert1804]

The firing pin bushing has a convex shape. When the primer is mashed into the bushing, its convex shape presses a corresponding concave shape in the primer. It makes them look flattened. If you look closely, the primer has a dished in shape. The difference between real visible pressure signs and a kaboomed revolver is not much. None of the pictures show any obvious pressure warning signs.

 

[Simson-Suhl]

One item I have noticed about primers can depend on who made them. I usually use CCI small pistol primers. Ran out and local dealers were out also. Purchased a carton of Federal. Same powder load, same bullet, same S&W Model 19-3. The Federal primers were flattened more than the CCI.
I do believe CCI primers have a thicker/harder cup than some of the others including Federal.

 

[rwsmith]

14.8 grains of 2400...

14.8 grains of 2400 for a 158 gr. bullet seems more like a TOP load to me. I believe that is where I start running into trouble with my .357 with locking up the cylinder. My 686 has the 'M' modification but if I get too raucous it will still lock the cylinder up, but right below that is no problem.

 

[99bob]

I gotta say something isn't right. I've never had a primer that flat. I'd start over from scratch starting with the loading manual data, weighed loads. You didn't empty a powder reservoir into the wrong can of powder by chance? Again, I'm no expert but those primers would scare me. How do the cases look? Are they getting bulges near the base?

Nothing noticeable to the naked eye. I just compared them to the PMC brass. It's about the same, maybe a little more.

The firing pin bushing has a convex shape. When the primer is mashed into the bushing, its convex shape presses a corresponding concave shape in the primer. It makes them look flattened. If you look closely, the primer has a dished in shape. The difference between real visible pressure signs and a kaboomed revolver is not much. None of the pictures show any obvious pressure warning signs.

Makes me feel a little better.

One item I have noticed about primers can depend on who made them. I usually use CCI small pistol primers. Ran out and local dealers were out also. Purchased a carton of Federal. Same powder load, same bullet, same S&W Model 19-3. The Federal primers were flattened more than the CCI.
I do believe CCI primers have a thicker/harder cup than some of the others including Federal.

Not a chance on mixing powders. I'm careful and only have one container out at a time. Long ago I threw away a container because I may have or may not have mixed them up as you said. Better safe than sorry.

I was wondering about the primers as well.

I'm still torn. I hate to throw these out/pull them.

 

[rwsmith]

CCI has been...

One item I have noticed about primers can depend on who made them. I usually use CCI small pistol primers. Ran out and local dealers were out also. Purchased a carton of Federal. Same powder load, same bullet, same S&W Model 19-3. The Federal primers were flattened more than the CCI.
I do believe CCI primers have a thicker/harder cup than some of the others including Federal.

CCI in the past was noted as a 'hard' primer. (domestic primers) I believe that the hardness of domestic primers have become more 'homogenized' over the last few years. Anecdotally, Federals were the softest. You might want to try CCIs or Remingtons.

 

[99bob]

14.8 grains of 2400 for a 158 gr. bullet seems more like a TOP load to me. I believe that is where I start running into trouble with my .357 with locking up the cylinder. My 686 has the 'M' modification but if I get too raucous it will still lock the cylinder up, but right below that is no problem.

Alliant has it listed at that and recommends no deviation. The only thing I did different was the primer. Alliant lists the CCI 500 primer.

 

[99bob]

The firing pin bushing has a convex shape. When the primer is mashed into the bushing, its convex shape presses a corresponding concave shape in the primer. It makes them look flattened. If you look closely, the primer has a dished in shape. The difference between real visible pressure signs and a kaboomed revolver is not much. None of the pictures show any obvious pressure warning signs.

What does an obvious pressure warning sign look like?

 

[muddocktor]

14.8 grains of 2400 for a 158 gr. bullet seems more like a TOP load to me. I believe that is where I start running into trouble with my .357 with locking up the cylinder. My 686 has the 'M' modification but if I get too raucous it will still lock the cylinder up, but right below that is no problem.

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?