How to tell incomplete powder burn?

[lonely_wolf]

Other than seeing a flame, is there anyway to know if all the powder is being burnt up in a barrel?

I'm thinking for 16"-18" barreled 308s. No point in working up loads if not all the powder will be burnt in the barrel (?)

 

[Aimsmall55]

Other than seeing a flame, is there anyway to know if all the powder is being burnt up in a barrel?

I'm thinking for 16"-18" barreled 308s. No point in working up loads if not all the powder will be burnt in the barrel (?)

Only way I could see " performance " and "powder burnt" is quickload.

 

[Xtremegunnr]

Put your hand in front of it and see if there is any residue after shooting

 

[lonely_wolf]

Put your hand in front of it and see if there is any residue after shooting

I guess I only have two chances to figure it out.

 

[turbo54]

You can see and smell it.

Seriously.

Watch and smell the muzzle smoke from a 24" 308 firing ~44gr Varget/175, then watch/smell a 16" 308 firing the same cartridges.

The short barrel will look/smell smokier.

 

[MarinePMI]

You could just do like the old muzzle loader guys used to do back in the day...shoot through some old white cloth held a few inches from the muzzle. Adjust your load until there aren't any residual, unburnt grains of powder stuck to the cloth...

IDK, maybe that's to simple(?).

 

[lonely_wolf]

Thank you eveyrone for the ideas. Seems simpler than I thought.

 

[Xtremegunnr]

No real science. Go with what works. I used reloader 17 in a 16" dta with 225 grain bullets. Maybe not full powder burn...i dont know...but it shot lights out at 1000 yards.

 

[sic65stang]

In some loads in my shorter rifles I see a plateau in velocity gain. I chocked it up to incomplete burn but dont know all the science behind it.

For example 43.5 varget produces 2525, 44 of varget produces 2575, 44.5 varget produces 2625, and 45 varget produces 2530. Those are just easy numbers but whenever I have seen the velocity slack off from previous increment gains thats what I assume happens.

 

[nuclear_shooter]

Couldn't you chrono the bullet, and plot the MV vs powder charge and see when you stop seeing significant increases in MV?

Edit: Ah, I see the poster above me suggested something similar!

 

[pawprint2]

In some loads in my shorter rifles I see a plateau in velocity gain. I chocked it up to incomplete burn but dont know all the science behind it.

For example 43.5 varget produces 2525, 44 of varget produces 2575, 44.5 varget produces 2625, and 45 varget produces 2530. Those are just easy numbers but whenever I have seen the velocity slack off from previous increment gains thats what I assume happens.

I believe what is actually happening here, is the density of the load in the case is failing to have the same speed of ignition due to the primer's specific temp/speed, therefore the pressure curve is longer. This can be verified by swapping to a magnum primer with the 45.0gr load (working up safely to that load of course).

 

[40xs]

Shoot it at night time. It will surprise you how much is still burning.

 

[ksthomas]

Large muzzle flash isn't necessarily (or even often) a sign of incomplete combustion. The powder gases are themselves, highly flammable. Even though the powder may be fully burned, the sudden infusion of oxygen as the gas cloud exits the muzzle into the open air often creates what is in effect a secondary explosion. This is what we often see as muzzle flash, and what many assume to be a sign of unburned powder exiting the bore.

Take a look at some of the instances where several shots are fired in very rapid succession, and only one out of several shots appears to have a noticeably more intense muzzle flash. That's simply the point at which enough gases became concentrated momentarily, but long enough to allow for the secondary explosive effect. This, incidentally, is also how prong-type (M14, for example) flash suppressors operate; by breaking those gases up significantly enough that they can't form the concentration and erupt into the secondary flash.

 

[Rprecision]

Depends on the caliber. The .308 isnt as handcapped by a short barrel. The show is mostly over 18-22"

Burn rate, caliber, bullet weight all factor into what you are looking at.

On short guns I have always started with a faster powder, one known to produce accuracy in the caliber, then work up a load. Where you end up is mostly up to the gun! I would rather loose out on 100 FPS and gain 1/2-1.0 moa of accuacy then chase the fast load.

 

[BuzzBoss915]

Yeah, good answers. You should use a slightly faster powder in a short barrel, just for the sake of efficiency. But, while I agree with what Mr Thomas wrote, it happens that I do a lot of night hunting coyotes and it is fairly easy to see extreme flash on a moonless night, and the cause is usually too much of a too slow powder, and these/my rifles are not equipped with flash hiders, they are more like bench guns, but with performance chamberings/Ackleys, for instance. Anyway, you/me can tell when you have this type of situation and it's not dialing back on the load, you need to drop down a notch or two on the burning rate. BB