Case head measurements in the 2nd post after OP. Speculate away. Thank you for your patience for those who were interested.

What is the purpose of all this?
 

Sounds like there was another incident at the pistol range on Friday. Seems to happen often over there, lot more than rifles...

Prob because pistols cheaper than bench rifles.  So no one wants to damage their rifle by being careless.

What is the purpose of all this?
 

Data. What I'm seeing, you're seeing. Minus a $700+ electronic pressure trace monitor.

Sounds like there was another incident at the pistol range on Friday. Seems to happen often over there, lot more than rifles...

Hate to hear of any mishaps. In reality, it happens.

My digital calipers can only discriminate the 10,000ths of an inch in increments of 5. So if I want to measure more accurately I will need micrometer.

I work in an industry that regularly uses micrometers and calipers. I do not know of any calipers that measures to .0001". .0005" is not enough to measure case head expansion. Precision machinist may have access to such a thing, I don't know. Micrometers are the only ones I know of.

I do reload both pistol and rifle calibers. I will say I do not push my pistol loads very hard as I do not have any reason to. I do on my rifle loads. Here's a link that may be worth looking into. It specifically references rifles. I do not know about pistols. .0005" is not enough. http://www.hodgdonreloading.com/reloading-education/tips-and-tricks/simple-trick-monitoring-pressure-your-rifle-reloads . Quick Loads may help you a lot. If you input good data, you'll get good results.

I work in an industry that regularly uses micrometers and calipers. I do not know of any calipers that measures to .0001". .0005" is not enough to measure case head expansion. Precision machinist may have access to such a thing, I don't know. Micrometers are the only ones I know of.

I do reload both pistol and rifle calibers. I will say I do not push my pistol loads very hard as I do not have any reason to. I do on my rifle loads. Here's a link that may be worth looking into. It specifically references rifles. I do not know about pistols. .0005" is not enough. http://www.hodgdonreloading.com/reloading-education/tips-and-tricks/simple-trick-monitoring-pressure-your-rifle-reloads . Quick Loads may help you a lot. If you input good data, you'll get good results.

My only question would be since chamber IDs vary from weapon to weapon even of the same make and model so I've heard, wouldn't they have different expansion readings?

Correct me if I'm wrong. A know standard pressure load fired from weapon A produces a measurement of X. Use known standard pressure load fired from weapon A as a baseline. Measure expansion as powder charge increases against known standard pressure case fired from weapon A.

As a welder I work close to a machinist in our shop. Maybe one day he will be kind enough to let me borrow his micrometer. Which he treats like a childhood blanket. He performs magic with his measuring tools, lathe and bridgeport. I'm trying to get him to mill and tap an optics slot on my P365. Meh, anyways I digress. I understand the acceptance of tolerances and safety nets for deviation because of that man. I will try to replace the caliper pictures with micrometer pictures one day.

I'm hoping to find just as much information on pistol cartridge expansion as there is rifle cartridge load development. For now all I was able to find was that Western Powders article.

As far as Quickloads I've read that the 2018 revision does not have CFE-Pistol Data added to the software yet. I'm hoping 2019's revision will. I will be investing in it soon.

My only question would be since chamber IDs vary from weapon to weapon even of the same make and model so I've heard, wouldn't they have different expansion readings?

Correct me if I'm wrong. A know standard pressure load fired from weapon A produces a measurement of X. Use known standard pressure load fired from weapon A as a baseline. Measure expansion as powder charge increases against known standard pressure case fired from weapon A.

I will say I'm not a ballistician, nor do I push my pistol loads hard, but I did stay at a Holiday Inn Express last night.  ----- No. I believe you are mistaking case BODY expansion from case HEAD expansion. The body will expand from loose or sloppy chambers more than say a quality match chamber. The case head which is the thickest most portion of the case will expand due to the pressure. Hence the use of BNIB cases so they are not affected by any previous firings. Case BODY expansion is not a good way to measure pressure nor do I feel reading primers is the most accurate. I could go on but I will say check with reliable sources for information, not YouTube. I can't direct you where to go for pistols though Accurate Shooters/ 6mmBR is one I consider pretty trustworthy for rifles. I did not read the article you linked. ---- I'm sure some may disagree with me, that's life!!.

i agree with bushido that you may be getting mixed up between case head expansion vs case wall expansion.

also, i know that there is a decent amount of variation between different pistol makers and the way that they decide to cut their chambers.  as an example, when i pick up fired brass, i can usually tell which ones were fired out of my VP9 since HK adds a small step in the chamber, which results in a ring around the brass.

since the whole point of you doing this "experiment" was to increase recoil, i suggest that you take oldfart's advice and switch to a different caliber.  go with 40S&W, 38 super, 357 sig, 45 acp, or 10mm.  i think any of those will give you the recoil you desire.

I will say I'm not a ballistician, nor do I push my pistol loads hard, but I did stay at a Holiday Inn Express last night.  ----- No. I believe you are mistaking case BODY expansion from case HEAD expansion. The body will expand from loose or sloppy chambers more than say a quality match chamber. The case head which is the thickest most portion of the case will expand due to the pressure. Hence the use of BNIB cases so they are not affected by any previous firings. Case BODY expansion is not a good way to measure pressure nor do I feel reading primers is the most accurate. I could go on but I will say check with reliable sources for information, not YouTube. I can't direct you where to go for pistols though Accurate Shooters/ 6mmBR is one I consider pretty trustworthy for rifles. I did not read the article you linked. ---- I'm sure some may disagree with me, that's life!!.

Lol!

I just checked my cases. Sorry I was wrong, .200" above the rim isn't the case body, it's the case head. Inside the case it is exactly where the webbing starts it's transition to the case wall. Measurements where on the case heads, gotta edit that.

I'm not going to make it to the bench tonight. But what I did was measured a batch of case heads of a factory loaded standard pressure Blazer Brass case or my stadnard pressure reloads, and compared them to the exact same spot mentioned in the article with my over the "over the book" charges.

IIRC standard factory and standard pressure reloaded Blazer Brass cases consistently measured .388" at the location .200" above the rim. The highest charge of 6.7gr varied between .389" thru .3895" at the same location. My digital calipers can only discriminate the 10,000ths of an inch in increments of 5. So if I want to measure more accurately I will need micrometer.

I will eventually get every little detail I find on this post eventually and share it with you guys through pictures.

Calipers will only be accurate to +/- .001 at best

What is the purpose of all this?
 

I was thinking the same thing

.  as an example, when i pick up fired brass, i can usually tell which ones were fired out of my VP9 since HK adds a small step in the chamber, which results in a ring around the brass.

I always wondered why pews is always picking up and staring at his brass.  For me, my rounds are fire and forget.  As long as they go bang, it's all G.

Using 5.9gr CFE-Pistol with this Lot# as a pet load, consistently hitting an 8" steel gong at 25 yards this morning and pinged it half the time at 50 and 75 with irons sights. I can't really ask more out of a handgun. I might see if I can hit that little bugger out at 200 yards today lol.

If you are using the everglades 124 fmj with 5.9 hogdon cfe, then you are 15% over hogdon max.
Your primers showed excess pressure signs from both guns. But you already knew this, right?

I ran major power factor loads for years in my old ipsc gun. Eventually it resulted in a cracked frame.
I love shooting that old pistol and showing people what a steady diet of full power ammo can do to your gun.

If you are using the everglades 124 fmj with 5.9 hogdon cfe, then you are 15% over hogdon max.
Your primers showed excess pressure signs from both guns. But you already knew this, right?

I ran major power factor loads for years in my old ipsc gun. Eventually it resulted in a cracked frame.
I love shooting that old pistol and showing people what a steady diet of full power ammo can do to your gun.

Not worried about it for my guns. I've done enough testing, measuring, inspecting, reloaded the same case with this load here in the field to feel comfortable production loading it for my Glocks and SIGs. Case scorching stopped at 5.9gr and is a laser beam load for me.

Spotter said I hit the chains once at 200 yards out of 20 rounds LMAO. That's a win in my book!

Inspecting my torture batch of cases today and got my first neck split. This one case out of a 100 round batch I've been using to torture the cases. This case has seen 6 loads of 5.9gr CFE Pistol.

Still no bulging or hair line cracks I can see on the case head. I will take neck splits before case head cracks everyday.

Wtf?!?!?

It looks like the head of your case blew out, which means that you’re teetering on the edge of a kaboom. I hope you like buying new pistols frequently.

Wtf?!?!?

It looks like the head of your case blew out, which means that you’re teetering on the edge of a kaboom. I hope you like buying new pistols frequently.

Lol yeah let's go with that,

aaaaaaaand that's the case mouth.

EDIT: I think I know what you might be looking at. That was just soot. Wiped it off and upped another picture for clarity

Is your test gun a 365?