sooty case question

Being in a longer barrel also gives it a longer time for the soot to blow by the case mouth. That may be why it looks worse than it really is.

Cliff6 said:

She asked why, and I had no answer.

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“Honey, cases are like dishes. They get dirty when we use them, and then we have to clean them before we use them again”. Don’t you guys speak Venusian?

I had a Metal Shop teacher that used to say "I can explain it to you, but I can't understand it for you"...

Cliff6 said:

My wife wanted to load some rounds for the first time today. While I was explaining things to her, I mentioned that very light loads tend to be sooty with most (if not all) gun powders. She asked why, and I had no answer. Anybody know why this happens?

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Yes. Think of smokeless powder as "fuel" and it will all become clear. If she has ever had a kerosene lantern, she knows that adjusting the wick not only makes the kerosene burn without soot on the glass chimney, but the lamp is also brighter. Same thing with cars and lawn mowers. When the 'choke' gets stuck ON, the excess fuel burns with lots of black smoke. The engine won't run fast or with any power until the mixture is 'leaned' out. Same thing with your BBQ grill. When you pour on the starter fluid the excessive amount of fuel burns with huge columns of black smoke until the fire gets hot enough to burn efficiently. Whatever the fuel... black soot is always a sign of inefficient fuel combustion. It's a normal part of combustion science.

When you burn fuel in a firearm, you don't have a "mixture control screw" like you do on a carburetor. Instead, reloaders raise combustion efficiency by raising the chamber pressure. We can do that 3 ways: 1) we can simply add more powder, 2) decrease the combustion space (seat the bullet deeper), or 3) find a slightly "faster" (aka "hotter") powder. So reloaders control the combustion efficiency by choosing the correct powder for the pressure, and burning it under the correct conditions. This is what Powder Burn Rate charts are all about.

You'll often see a discussion on THR about (say for instance using Unique in 38Spcl). One guy says is burns 'sooty', the next guy says it burns 'clean'. They are BOTH correct, but only one of them has figured out how to burn it efficiently !! So the first thing you want to do when you pick up one of your cases from a new load is to look at the "color of the burn". That may tell you more than the chrono !

What is "efficiency" ? Basically, efficiency is doing more with less, or getting the most out of your fuel. As with the kerosene lantern, it's easy to see you get more light when you turn the wick down to where all the fuel is being completely consumed. So when the interiors of your cases are clean (possibly with a tan or light gray coloration) you can tell you're getting the most from your loads. A proof of what I'm saying, simply Google up a spark plug chart and look at the images. The spark plugs labeled "good" are light tan and/or light gray.

Hope this helps.

Demi-human said:

I learn by screwing it up a bunch first...

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Experience is nothing but the result of a series of non-fatal errors.

Not sure what or how much you crimped OP but if it was a light crimp you might set your dies to give a bit more. This may increase the dwell time increasing pressure in the case to expand it a bit more as the bullet jumps the crimp to the rifling.

Rockrivr1 said:

These particular casings were from factory cowboy rounds. They advertised 720 FPS on them. I'm guessing that is too low for this particular rifle. I'm ramping up to start reloading 45LC so I'm assuming I'll need to be looking to be higher then that.

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So, there it is. That's a pretty bland load and/but about right for cowboy action. Not high pressure at all. I would expect a lot of soot blow-back from that. Maybe an equivalent to black powder? Lots of smoke? Anyway, biggie difference between that and a 1,000 fps and up.

Hodgdon has a lot of info on the 45 Colt, btw. Have fun.