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Old April 29, 2015, 05:56 PM   #1
litenite99
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9mm help brass has powder residue

wondering if anyone can tell me what the problem is. I shot these about 30 min ago and immediately noticed the residue on the brass. Not sure whats causing this.
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Old April 29, 2015, 05:56 PM   #2
jwrowland77
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Titegroup?
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Old April 29, 2015, 05:58 PM   #3
litenite99
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vihtavouri n320
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Old April 29, 2015, 06:17 PM   #4
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In my opinion, the cartridge case is not fully obdurated throughout the entire firing cycle. This is not a problem as long as some of the case stays obdurated when pressures are high. The cartridge case is a gas seal, it swells up under pressure and keeps combustion gases from escaping the breech. However, sometimes brass hardness, pressure curve, portions of the case are a bit late in expanding to the chamber walls, or relax early. There are funnies with rifle case mouths and how they stay curled after extraction. But, the bottom line is unless you have having gas venting at high pressure through the breech, you don't have a function problem.

Here is an example of a breech where the front of the case will come out smoky and sooty, and by design. The fluted chamber is a great idea as it breaks the friction between case and chamber, reducing friction between case and chamber, which improves extraction reliability. When cases are stuck to the chamber walls this often results in failures to extract in auto guns. The Russians are the most likely inventors of fluted chambers, and as you can see, the upper 2/3 rds of the case is floated off the chamber. The back third is the case seal. It does result in dirty cases, but so what, if function is improved, that is a good tradeoff.




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Old April 29, 2015, 06:25 PM   #5
litenite99
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thats pretty interesting ive never seen flutted chambers before. i was worried i wasnt loading hot enough, and also that the soot was from gas as u stated but that it may damage my pistol since its in the same area on every bullet.
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Old April 29, 2015, 06:34 PM   #6
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Quote:
thats pretty interesting ive never seen flutted chambers before. i was worried i wasnt loading hot enough, and also that the soot was from gas as u stated but that it may damage my pistol since its in the same area on every bullet.
The only real negative result is that you will need to be dedicated in cleaning the chamber out. And for semi autos, you should always keep that chamber clean for best function reliability. With enough fouling, breech friction will defeat even the best semi automatic mechanism as friction between the gunk, case, and chamber will stick the case in the chamber.

For my auto pistols, I make sure that I run an bore brush, or slightly over sized bore brush, through the chamber and scrub out all dirt. And I lightly lube my chambers. This weekend, during a 2700 Bullseye match, I was dripping drops of oil over the cartridge stack of my M1911 to ensure best extraction under low pressure. This is messy, but it works.
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Old April 29, 2015, 07:42 PM   #7
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Low pressure
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Old April 29, 2015, 08:20 PM   #8
litenite99
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i was worried it was low pressure the funny thing is that those bullets were loaded to 4.3 grains of n320 for 115gr max load is 4.4..... am i missing something here lol
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Old April 30, 2015, 01:08 AM   #9
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Soot, not powder.
Soot on case means that the pressure wasn't enough to seal the chamber.
Bullseye shooters fire thousands of round like this and no harm to guns.
EVERY reloading manual covers this.
The load in a manual shows what the lab got with their specific gun using their specific lots of components and a particular bullet at a particular COL.
You probably had different cases, different primers, different powder lot, different bullet lot if not a completely different bullet, and certainly a different gun.
Since every manual has slightly different max loads, why would you expect to get the same results one lab got?
Be aware that N310 throws off pressure spikes. Sometimes I suspect the max load (particularly for N310, Clays, and TiteGroup) was only a max load due to a pressure spike and not the average peak mean pressure. SAAMI has at least three pressure calculations and the load has to be below each one.
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Old April 30, 2015, 04:55 AM   #10
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You're really on the fast burning side of the spectrum.
I like slower burning powders for the safety margin they provide.
The cases are more full of powder, which means more consistent numbers, more power, and less chance of double charging.
I like 124 grain bullets better, too.
I use power pistol, WSF, unique, etc.

You see this in the cheaper factory loads, too, like win 100 round value packs.
Bang, pop, pop, bang, BANG, pop, pop.
115 grain bullets and fast powder. Eew.
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Old April 30, 2015, 05:00 PM   #11
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Pull a few, see what you have. And/or crono.
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