Over Pressure?

[indyblue]

Are these signs of too hot a load, do I need to back off?

But even the factory rounds have some apparent primer bulging. Notice the primers do not protrude from their pockets, the primers just look a bit stressed.
The cases near the base don't look bulged or stressed though, so maybe it's OK?

The cases with brass colored primers are factory rounds and the silver colored ones are my handloads with CCI primers.
All shot from a 92fs

125gr FMJ
4.2 gr W231
OAL=1.143-1.147.

 

[Gaffer]

From the loading data I have seen you are about right in the middle, so should be good to go. I might try a different handgun just to see if you get the same results??

I don't remember any of my round's primers looking like that.

Ron

 

[Wabatuckian]

I think they're ok. They're not flattened.

Actually -- and keep in mind I don't load 9mm, just .45acp in pistol -- lighter loads lead to primers backing out a smidge because they're not slamming the breachface as hard. I bet -- and you do this at your own risk -- you bump that up another tenth or two and your primers will normalize.

Federal and CCI primers have different hardnesses, too. I'd only compare apples to apples.

 

[EyeCarry]

I think they're ok. They're not flattened.

Actually -- and keep in mind I don't load 9mm, just .45acp in pistol -- lighter loads lead to primers backing out a smidge because they're not slamming the breachface as hard. I bet -- and you do this at your own risk -- you bump that up another tenth or two and your primers will normalize.

Federal and CCI primers have different hardnesses, too. I'd only compare apples to apples.

I've had some in the past like the OPs. I did not think about it this way though(just a bit light on powder).

 

[indyblue]

I've had some in the past like the OPs. I did not think about it this way though(just a bit light on powder).

My first batch of handloads were 4.1gr W231 and I read that if the cases come out dirty to bump the charge a bit to increase the seal in the chamber (fire forming?) so I went up to 4.2gr to check results. Cases come out pretty clean, I just noticed the pattern on the primers and got a little concerned.

So the suggestion may be to increase the charge a bit and it might "normalize" the primer issue?

 

[Wabatuckian]

My first batch of handloads were 4.1gr W231 and I read that if the cases come out dirty to bump the charge a bit to increase the seal in the chamber (fire forming?) so I went up to 4.2gr to check results. Cases come out pretty clean, I just noticed the pattern on the primers and got a little concerned.

So the suggestion may be to increase the charge a bit and it might "normalize" the primer issue?

Correct.

In fact, one of the first things I looked at were the cases themselves. Was looking for soot near the mouths.

Cases seal the breach by expanding under pressure. They contract a bit as pressure falls to allow extraction.

 

[Leadeye]

Primers look OK. I look for primers that look like they have "muffin top" when decapped.

 

[Creedmoor]

Primers look OK. I look for primers that look like they have "muffin top" when decapped.

Hey, you cant use that Pronoun any longer.
Some of us are sensitive about that.

 

[Paul 7.62]

Remember one thing guys primers don't tell much of a tale in most hand guns, and 9 mm is only a 35,000 psi round. Now if we were talking a 60,000 psi round, then primers are going to tell us more about pressure, even then we need to look at case head expansion, and other signs like heavy bolt lift, torn case heads and the like.

 

[DadSmith]

In my younger not so bright days I had pushed a 300gr XTP 44mag load to where the primer flattened.
All it took was 0.1gr more than what I had been using.
Just trying to point out once you reach the limit on pressure it doesn't take much to be over pressured.
Another thing when you are pursuing velocity always trickle charge when you are at the maximum recommended load, and load no more than 10rds to test. That way you have fewer to pull if its too much pressure.

 

[Aszerigan]

Undercharging a round can be more dangerous than overcharging one, especially with some powders like H110.

Also, people seem to worry more than they should about flattening primers. That’s just a sign of a mild over pressure, but most guns are made to handle a 30% overpressure situation. That’s why you ladder your rounds, not just make 500 at max charge.

I’ve flattened countless primers, especially in my 44 Mag and my 22-250. Never had an issue, it’s just the round telling you to back off a little. If you stay within the confines of a reloading manual, you’ll be good to go.

(edited from my phone's auto-correct)

 

[Aszerigan]

Also, flattening primers is a normal experience. Piercing primers is another story and should be avoided all together.

 

[Paul 7.62]

Also, flattening primers is a normal experience. Piercing primers is another story and should be avoided all together.

Flattened primers is a warning, just a small difference in the case, bullet or bore and you go from flattened to losing any rounded edge of the primer. Then case head expansion becomes a problem, and loose primer pockets or worse. If your primer is made of a brass cup, brass flows at 70,000 to 80,000 PSI. Some primer manufactures have used other material, so your mileage may vary. One thing not mentioned here is primer seating depth and what effect it has on primer flatting. I cut primer pockets on my brass for accuracy so I have 0.005" below case head. I can see differences between my SRP and LRP in my 6 XC and 308 Palma Brass as the LRP will flatten out more but the case head expansion is less, as I can drive my SRP brass faster.

 

[indyblue]

I get what you’re saying here, but since I cannot find load data for my exact bullet, I’m just trying to find the safe sweet spot. this is my first time through developing many of these loads.

Depending on the data book I use (and bullet type & wieght), I’m either right in the middle or I’m near max load.

I’ve been using the Hodgdon data for the sierra 125 gr FMJ, which is as close to these Armscor 125’s as I can find shows 4.4 to 4.8 g of 231.

The speer data for 125 lrn is 3.8 to 4.1 grains. And 124gr TMJ is 4.0 to 4.5 grains.

Other than the unusual patterns of my primers I see no indications of case bulging, or stress.

 

[Paul 7.62]

I get what you’re saying here, but since I cannot find load data for my exact bullet, I’m just trying to find the safe sweet spot. this is my first time through developing many of these loads.

Depending on the data book I use (and bullet type & wieght), I’m either right in the middle or I’m near max load.

I’ve been using the Hodgdon data for the sierra 125 gr FMJ, which is as close to these Armscor 125’s as I can find shows 4.4 to 4.8 g of 231.

The speer data for 125 lrn is 3.8 to 4.1 grains. And 124gr TMJ is 4.0 to 4.5 grains.

Other than the unusual patterns of my primers I see no indications of case bulging, or stress.

Per Sierra book 4.1 grains of WW231 is max for the 125 grain Sierra bullet and OAL is 1.090