Unburned Powder or Unburnable Powder?


Matt 357
May 23, 2010, 07:38 PM
Went to the range today and shot 50 rounds of 357 reloaded with H110 and 100 rounds of 38 special reloaded with SR4756. I toss my spent cases in a tupperware container during shooting. I noticed "powder" collecting at the bottom of the container. Ah hah. Unburned powder! When I got home I shook the hell out of the container to knock out any extra powder from the cases. Altogether about 0.5cc of crap. I put the little pile on a 2x4 and hit it with a BBQ lighter. No poof, just a fizzle. And after the fizzle about 50% of the crap was left as unburnable ash.

Hmmm.... So when you think there is unburned powder from your handloads, is it really unburned or unburnable?

BTW not sure if unburnable is a word. Noncombustible is probably more correct.

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May 23, 2010, 08:43 PM
SR 4756 burns very clean at good pressures, but is very position sensitive and does not do well if the powder is forward, like it can be in a .38 case. (I tried 6.0 Grs of SR 4756 in a .357 case with a125 Gr plated bullet. 12 rounds powder back gave an average 931 FPS. The first shot powder forward stuck the bullet in the barrel)

H110 Needs a good crimp and a near full charge to burn well.

Either one of those things could have been going on.

Matt 357
May 24, 2010, 10:32 AM
Yup... read all about the tips on SR4756 and H110. In addition to pressure/combustion issues, I am wondering if these particles I found are like the kernels at the bottom of a bag of microwave popcorn. Some kernels just won't pop. So out of say 10 grains of powder, should 100% of the powder vaporize?

When we say a powder burns "clean", are we talking zero residue? If not, how much residue in the barrel is normal after firing a few rounds? Pictures of barrel showing clean burn and unburned powder would be great if anyone has the time. Next time I go shooting I'll take some pics before cleaning.

May 24, 2010, 11:00 AM
Every "granule" should burn. There will be a tiny bit if residue with any powder. How clean it is capable of burning is measured by what material it is made from. What kind of cellulose in other words - wood pulp, which is very common, cotton, which is used by Vihtavuori, etc., and how clean the raw material is.

Steve C
May 24, 2010, 04:30 PM
There's no reason to assume that powder will burn completely, few thing do. You burn paper which is plant fiber that's cellulose and there's ash. Smokeless gunpowder is mostly nitrocellulose or nitrocellulose with nitroglycerin and other components that help stabilize the nitrocellulose. Nitrocellulose is a nitrated paper or plant fiber so some solid remnants are expected though most of it is sent out the muzzle. While some of the residue is flakes of powder that didn't get ignited a good amount of what you see is simply ash.

May 24, 2010, 10:20 PM
I've noticed similar residue in whatever container I keep my fire .38 special or .357 magnum brass. Coming out of a 2.25" SP101, I had assumed that it was unburnt powder and not put a second thought to it being a snubbie. Thinking about it now, most of it (in the barrel too) was translucent, almost crystalline in appearance. Is this also just leftover "ash"?

May 25, 2010, 12:17 AM
Would faster burning powder like Bullseye/Red Dot/Promo/700X minimize unburnt powder in short barreled gun?

Phil A
May 25, 2010, 11:31 PM
H110 in the .357 burns better with magnum primers however I still prefer a faster powder for the .357. I have .44 mag in a Contender (14" barrel) than does very well with H110. - Phil

May 25, 2010, 11:41 PM
In .460 S&W H110 needed a really tight crimp to burn. Lil' Gun worked much better. I've got about 6 lbs of Lil' Gun I need to get rid of because my very soon-to-be ex-wife stole the gun and sold it. :(

Matt 357
May 26, 2010, 10:13 AM
I'm still curious about how much unburned powder/ash is way too much. Is it reasonable to see some particles in the barrel?

If you take 100 spent cases and shake out the crap, how much crap it reasonable? Again, just curious. I have 2 pounds of H110. It shoots nicely with 180 grain JHP.
Just trying to get a feel for what's "typical".

May 26, 2010, 11:17 AM
You should not have unburned or half burned granules in the barrel if you are getting good combustion. I posted the two reasons I thought might be causing it in post #2.

May 26, 2010, 01:06 PM
What you are seeing is powder "skeletons".
The powder did burn, and what you are seeing is mostly left-over ash skeletons of the powder flakes.

It is somewhat common at less then max pressure load levels.


May 26, 2010, 08:35 PM
When I have seen true unburned powder it looked like clumps of yellow chalk.

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