Incomplete Powder Burn on .38spl

[mousegun380]

Hello,

I've been loading several other pistol calibers and just started with .38spl. I worked up some loads and have been doing fine. I don't remember any incomplete powder burning issues. However, I decided to work up a load using magnum primers since they have been more available lately than regular. I started with 2.8gr, 3.1gr, and 3.4gr of Unique. All three had unburned powder left in the barrel, but all also shot well and achieved the expected velocity. it did not appear to be just powder residue but rather the actual flakes of Unique still unburned.

Any ideas? I would have thought that the magnum primer would have initiated a more complete powder burn than the standard due to additional points of ignition.

Thanks

 

[Nate1778]

Unique burns better at higher pressures, it also burns cleaner. Go to Alliants site as your loads look pretty light, the recommended load for my 158 grain Bullet is 4.7 grains. I have noticed the higher you push the pressures the cleaner it burns.

I have also switched to Red Dot in my .357 shooting .38s and the groupings are much tighter. Its a 6" barrel gun by the way. Seams like your load is a bit light, even for a magnum primer. Post bullet and gun type for better info.

 

[mousegun380]

Cool. Makes sense. I was just very wary of the magnum primer. Sounds like I should step them up a bit. Thanks

 

[Ben Shepherd]

Step them up a bit, and also make sure your neck tension and crimp are adequate.

Crimp doesn't need to be heavy, but it does need to be there, and you should be able to lightly see the outline of the bullet in the case if your neck tension is correct.

 

[rcmodel]

+1 on way too light.

Bump it up.

But even then, you may still see a few powder "skeletons" left over.

Alliant flake type powder may often leave burned powder skeletons.

It is harmless.

rc

 

[Walkalong]

Alliant Red Dot & American Select will not leave flakes at low .38 Pressures.

 

[jjohnson]

Higher Pressure and Faster Powders

Right - that 'skeleton' is a key indicator.

When your powder charge is ignited, the pressure momentarily seals the casing against the walls of the chambers, making a gas seal for an instant. If your pressure is too low, you won't get a seal, and there will be a streak of soot on your brass. This means you need more pressure by using more powder, faster powder, heavier bullet, or some combination of those. This is why new handloaders who're trying to get all they can out of their new hobby claim that their powders are burning "dirty." The factory ammo you buy usually isn't that weak. If you bump your loads up around the middle of what the powder manufacturers recommend, you'll see the problem vanish, unless you're using powder that's too slow to begin with.

There's a very handy software program called Quickload that can tell you how much powder is burned by a given charge of powder with a given barrel length. When I develop loads, I check it with Quickload to see how efficient the burn is.

If you don't want to pay for Quickload, take a look at the powder burn rate charts, find one of the faster powders, use it for your loads, and see what happens. I use a lot of Unique, but for some cartridges, (like .38 Special in a snubnose) you'll find powders like Red Dot or Titegroup more efficient.