Are Cleaner Loads correlated to Higher Pressures?

H

Highbrass

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CAUTION: The following post includes loading data beyond or not covered by currently published maximums for this cartridge. USE AT YOUR OWN RISK. Neither the writer, The Firing Line, nor the staff of TFL assume any liability for any damage or injury resulting from use of this information.

Hi,

I have been reloading for 8 months now and have obtained some great results in .380 auto, 9mm Luger and .223. Our rounds have been very accurate and cycle well.

One thing I am looking to do is to make them as clean as possible. Some of them, particular the .380 and 9mm pistol cartridges can get some soot on one side of the spent brass. I understand this is because the cartridge is not fully expanding against the chamber wall and gas is leaking back.

Question is, are cleaner loads correlated to a higher powder charge and higher pressures? We are loading OAL to the factory spec.

One specific example is we are loading a 100 grain Berry plated RN over 3.1 grains of HP-38. Hornady's loading manual lists the max load at 3.1, and the identical Win231 at 3.3. Just wondering if we had any leeway on taking the powder up slightly (.1) to get a better seal and cleaner round? Our spent cases show absolutely no signs of excessive pressure.

I would appreciate your thoughts on this.
 
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It will be nearly impossible to see pressure sights on 380. I would look for another powder like titegroup. I only mention this because my titegroup 380 loads are pretty clean.

I would personally avoid going over max charge at all cost.

Funny thing is, I usually get the dangerous reloaders tag on my posts when I suggest being within the upper 10% of the charge range!
 
Hi, and welcome to TFL.

Question is, are cleaner loads correlated to a higher powder charge and higher pressures?
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Basically, yes. Basically

But then that pesky reality gets in the way. There are a lot of variables. Primers, bullet weight, bullet diameter, burn rate of the propellant, amount of crimp, and probably others.

Generally, the slower the burn rate, the more pressure required to get the propellant to "clean up." i.e., faster powders' running sooty is rarely an issue; conversely, slower powders is where sootiness tends to manifest itself.

Perspective. If your firearms are cycling and the bullets are going where you point them, then how high of a priority is cleanliness? In many instances, you can have your cake and eat it too. But never loose sight of the big picture and what's really important.

HP-38 (or W231 - they are the same propellant in different packaging) is a dirty powder.
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Heh. Allrightythen. That is the first time I've ever heard of W231 characterized in such a way. W231 has a long running reputation of burning clean. And that's because it does. Rewind back to 1985: I was looking for something that runs cleaner than Bullseye and was directed to W231. I've had W231 in my arsenal ever since. It runs clean.

Of course, if you turn down any propellant low enough, it'll run sooty. Nitro-100 is THE fastest propellant; and I have turned it down so low that it ran sooty.

Soot on the side of the brass (known as blowback) is not a good indicator of peak pressure; nor is it an indicator of the propellant running sooty overall. There are a lot of dynamics going on when firing pin meets primer. Once the bullet dislodges from the case mouth, burning propellant begins to escape along with the bullet. But that moment is rarely peak pressure. And that moment is when you're likely getting your brass blowback marks. I've seen some pretty hot ammo with blowback soot on the brass. That's one of the pressure "tea leaves" not worth reading.

Perspective. Learn not to chase ghosts.
 
Nick C S wrote:
...faster powders' running sooty is rarely an issue;...
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The faster the powder, the more quickly pressure rises within the case before the inertia of the bullet is overcome and it starts moving which will allow the propellant gasses to escape the case and flow around the sides if they have not already made contact with the wall of the chamber.

A powder can be "dirty" in that it leaves behind a lot of residue in the barrel (and in the case of semi-automatics, throughout the action) but still leave clean cases because it burns "dirty" very quickly and so seals the case against the chamber wall. So, when someone tells you a powder is "dirty" make sure to get them to explain how they mean you to understand the term.
 
Highbrass, welcome to the forum.

Yes, the peak pressure you run at can affect the amount of unburned powder in the barrel by making it burn up faster. HP38 and 231 are, indeed, the same powders (Both St. Marks OBP231 in a canister grade). If you look at the data on their distributor's site (Hodgdon distributes both) you will find the data is identical. The Hornady data difference between the two is most likely due to the particular lots they got of each being a little different in burn rate.

The .380 is a low-ish pressure cartridge, about like .45 Auto at 17,000 CUP. There is some disagreement between the 1992 and 2015 SAAMI standards, which give 26,500 psi and 21,500 psi as the transducer pressures, respectively, but they agree on 17,000 CUP, so this must be an instrumentation issue. If you were shooting 9mm Luger, you would have enough more pressure to see some difference in powder burn.

As mentioned, there are also cleaner powders these days. Hodgdon Universal Clays doesn't have the graphite layer many powders do, with the result it blows less of that stuff around, which makes a surprising difference. Because powder burning is an oxygen starved reaction, though, you always have something left behind.
 
I do not belief that it is like that, it all depends on the kind of powder and primer you use. To drive smokey powder beyond maximum load to see if it is less smokey could be dangerous. Some primers gives better combustion than other. The answer is therefore that different primers might help, but it is not absolute.
 
Just my opinion. I shot and reloaded several years before I went on line. I understand that shooting will result in GSR, which bothers some and is of very little importance to others, but seems to be a big topic for newer reloaders on forums today. In theory, I believe that powder needs a certain pressure to burn "cleaner", but I place more importance on functioning and accuracy.

When I shot in indoor ranges, all of them had restrooms with running water and soap to wash up and I always had a rag/towel or two in my range bag to wipe my hands and guns while I was shooting. When I shoot outdoors at the "range" I take water and towels/rags to rinse off any soot). I didn't wear my "Sunday-go-to-meeting" clothes to the range so I wasn't concerned about "dirty" powders. I would recommend that anyone that doesn't shoot black powder concentrate on factors other than how "clean" a powder burns (I have fired 250 rounds of 45 ACP with old "dirty" Unique and while the exterior of my gun may have been sooty, it functioned w/o a single malfunction due to "dirty powder"and my shooting friend normally would shoot double that per session)...

I can only suggest that if "clean" powder is important the reloader experiment with various powders until he finds one "clean" enough to use...
 
"...cartridge is not fully expanding..." Usually but not always. That's not a clean vs dirty powder thing though. The 'clean' part is about the powder, not the load.
"..."Sunday-go-to-meeting" clothes to the range..." Savage. Knew a guy whose whole team played paint ball in a suit and tie. snicker.
 
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