Pressure Limits

[Lefty7mmstw]

Face it, most guys are exceeding 70 Kpsi (sometimes rather significantly) already on their bragging rights type handloads. They aren't going to gain that much with "peak alloy" or any other casing. They already cry when they can't get 300 fps over book without destroying the primer pockets in x brand of brass and love y brand because it'll take any abuse they give it.
I've worked with Pressure Trace as have a few others here. Signs don't magically show up at 60Kpsi or 65Kpsi because Saami says they should.

 

[Lefty7mmstw]

Biggest factor for me running the Pressure Trace is brass head hardness.
Some brands will show excessive pressure signs well below max pressure because the brass is soft. Federal brass and Hornady brass are the worst for this.

Cheers.

Possibly some lots from those brands. Not across the board though.
I'm running a 220 Hornady (or Nosler) with a dump truck load of v570 in Fed brass in my Impulse in 300win and getting north of 2900 fps from it. The fed brass has multiple firings on it already and has been good for reloads with that combo.
I run reformed 243w or 308w Fed. brass in my Striker in 7-08 and the stuff takes multiple firings of full throttle loads fine. I'm sure other brands may last a touch better, but this stuff was free and it's uniform enough to be accurate.
Same for 30-06, 270w, and a host of other cartridges.
I've run Hornady for hundreds of rounds of 405w and haven't lost a single case. I'm more of a fan of Hornady bullets than the brass, but the brass is usually decent.

 

[Phil Rizzo]

One thing is for certain, being on the edge of what your brass can handle

Possibly some lots from those brands. Not across the board though.
I'm running a 220 Hornady (or Nosler) with a dump truck load of v570 in Fed brass in my Impulse in 300win and getting north of 2900 fps from it. The fed brass has multiple firings on it already and has been good for reloads with that combo.
I run reformed 243w or 308w Fed. brass in my Striker in 7-08 and the stuff takes multiple firings of full throttle loads fine. I'm sure other brands may last a touch better, but this stuff was free and it's uniform enough to be accurate.
Same for 30-06, 270w, and a host of other cartridges.
I've run Hornady for hundreds of rounds of 405w and haven't lost a single case. I'm more of a fan of Hornady bullets than the brass, but the brass is usually decent.

dang you just reminded me of my single shot .405
That **** thing kicks with 300's and factory loads. And it has rubber, not that steel plate.
My uncle gave me some reloads and it took about 2 shots with them to appreciate the awesome precision and comfort from my Hornady factory loads! Plenty good.

 

[G Arlen Good]

Years ago... I was struggling to find a reasonable maximum chamber pressure for my 357 Herrett. I was using a Super 14 Thompson Contender and since it was (is) a Wildcat cartridge, there is no SAAMI pressure standard. You'll find 35,000 psi bandied about.
The parent cartridge for the 357 Herrett is the Winchester 30-30 (SAAMI MAP 42,000 psi). Now, I am a firm believer in common sense... and Ocam's razor, so I calculated the Bolt Thrust for the 30-30 Winchester and developed loads for my 357 Herrett that did not exceed the Bolt Thrust pressure determined for the 30-30 Winchester. This pretty much matched the MAP. I did this a long time ago and have shot a lot of IHMSA events using my Herritt at near maximum velocity (i.e. chamber pressure). Enough to develop a very good level of confidence about what is going on. AND... I have no frame stretching.
I believe that the critical thing about the whole pressure issue is Standard Deviation. If you load to an average chamber pressure, half the loads will exceed that pressure. The critical question is, "By how much?" Your Standard Deviation will tell you that... and you must use 3 SIGMA precision to get those outliers. Since SAAMI usually tests to 130-150% recommended chamber pressure, small fluctuations may... MAY... be trivial. Your primers will whisper to you, so listen. Your firearm will whisper to you, so pay attention. The voice in the back of your head will whisper, too... so, for God's sake, pay attention. If your primers are screaming at you, you're not paying attention to something important. We call that being, "dumb." Don't be dumb.
So, I have developed a method that I believe is safe and reasonable to adjust maximum chamber pressure when needed. In my example above, I use 42,000 psi as the MAP for my 357 Herrett. That is the the upper pressure for 3 SIGMAs of Standard Deviation for my muzzle velocity. I get about 10 fps SD on my Herrett loads... so I adjust my powder charge to never exceed 30 fps above my maximum load. That easily converts to a maximum powder charge. But, watch your station temperature.
I believe that this process will work for other loads, too. I am also overly curious and I am always "what if'ing"... but, I have all ten fingers and both eyes after 50 years of reloading and experimentation.

Best regards

 

[82nd Bill]

Years ago... I was struggling to find a reasonable maximum chamber pressure for my 357 Herrett. I was using a Super 14 Thompson Contender and since it was (is) a Wildcat cartridge, there is no SAAMI pressure standard. You'll find 35,000 psi bandied about.
The parent cartridge for the 357 Herrett is the Winchester 30-30 (SAAMI MAP 42,000 psi). Now, I am a firm believer in common sense... and Ocam's razor, so I calculated the Bolt Thrust for the 30-30 Winchester and developed loads for my 357 Herrett that did not exceed the Bolt Thrust pressure determined for the 30-30 Winchester. This pretty much matched the MAP. I did this a long time ago and have shot a lot of IHMSA events using my Herritt at near maximum velocity (i.e. chamber pressure). Enough to develop a very good level of confidence about what is going on. AND... I have no frame stretching.
I believe that the critical thing about the whole pressure issue is Standard Deviation. If you load to an average chamber pressure, half the loads will exceed that pressure. The critical question is, "By how much?" Your Standard Deviation will tell you that... and you must use 3 SIGMA precision to get those outliers. Since SAAMI usually tests to 130-150% recommended chamber pressure, small fluctuations may... MAY... be trivial. Your primers will whisper to you, so listen. Your firearm will whisper to you, so pay attention. The voice in the back of your head will whisper, too... so, for God's sake, pay attention. If your primers are screaming at you, you're not paying attention to something important. We call that being, "dumb." Don't be dumb.
So, I have developed a method that I believe is safe and reasonable to adjust maximum chamber pressure when needed. In my example above, I use 42,000 psi as the MAP for my 357 Herrett. That is the the upper pressure for 3 SIGMAs of Standard Deviation for my muzzle velocity. I get about 10 fps SD on my Herrett loads... so I adjust my powder charge to never exceed 30 fps above my maximum load. That easily converts to a maximum powder charge. But, watch your station temperature.
I believe that this process will work for other loads, too. I am also overly curious and I am always "what if'ing"... but, I have all ten fingers and both eyes after 50 years of reloading and experimentation.

Best regards

Nicely laid out. But some will read it and forget it. Dumb

I have been playing with wild cats for 30+ years, and they will test your ability to create safe and functional loads. In my shot logbook I also record the case web dimension as yet another method of catching pressure before it becomes excessive. My personal method of checking loads is .2 grains, one shot each until i hit the first sign of pressure and .3 grains less is my max. I am currently working on a 25 WSM and it was hard to find the top so I starting backing it down when it had a little snappy recoil but nothing else, from 3,625 to an accuracy node that worked for me. Single digit SD,s in 60-90 F temp range So, it has been leveled out at 3,520. 100 rounds and zero issues and I know it could go faster but I have to stop my ego and stay safe, enjoy smother recoil, longer barrel life (maybe) and drop critters DRT.
High pressures can be very serious issues and just because it worked for 10-20 rounds maybe not so much in a temp rise, a hot barrel or chamber or dirty barrel, or some odd reloading mistake or powder issue. I have seen the effect of an overpressure round incident, and it isn't pretty.
Listen to your fired case and to your rifle. Stay safe.