Muzzle flash or: WOW, whazzat??

[22lovr]

I didn't have any Georgia Arms left for range practice with my brand new Taurus 605 so I got some el-cheapo Atlanta Arms reloads to practice with.

Do some of you remember the old-time photographers when they used "flash powder" when taking a portrait? You know.....poof!

Well, I touched off about 25 of these rounds and lit up our darkened indoor range like a flame thrower!

Okay, powder experts, give me a short course on powders and why some are very low in the pyrotechnics department while others are so glaringingly bright they could be seen from 20 miles away? How do the better ammo companies suppress muzzle flash and still get good velocity? I don't know squat about powder!

 

[Mike Irwin]

Couple of possible causes....

Some of the powder continuing to burn outside of the barrel.

The propellant gasses, under high heat and pressure, become incandescent.

Some powders, due to their burning characteristics, aren't as prone to one or another, and other powders have flash inhibitors added.

 

[Jim March]

What Mike said.

I think one of the flash suppressor additives they use is potassium powder? Not entirely sure.

In a perfect world, the amount of powder and the "burn rate" of the powder chosen would be tuned to your barrel length. You're supposed to "run out of fire" just as the bullet clears the muzzle.

Truly anal handloaders with a lot of time on their hands can get close to this with experimentation. The "proper perfect charge" will vary between specimens of gun, sometimes with the same barrel length .

It gets really bad when a caliber is usually used in rifles, but you shoot it in a handgun. .22Magnum is notorious for major fireballs and "big bullet noise levels" for exactly this reason, despite it being a runt. The loons who buy .45-70 handguns run into the same problem in it's most severe form when they shoot factory stuff...they mostly handload.

Sounds like you got some cheap ammo that wasn't even close to being "tuned".

 

[Cal4D4]

Flashiest I've seen has got to be the .223 in a Contender 10". I think the standard rifle loading is BL-C(2) or about there.

Uncompounded Potassium metal is probably way too reactive to be blended into powders. A flash suppressor would need to cool the burn temp a bit. I think Krupp guns used sacks of Calcium Nitrate, but I would need to look that up. Imagine trying to limit that muzzle flash!

 

[C.R.Sam]

Mike got it pretty well.

Mixing your own low (or high) flash powder can be hazardous to your hands and gun. Often the additives not only change the burn rate but also alter the shape of the pressure curve. Hence sometimes getting some pretty spikey PEAK pressures while the total pressure is low.

One of the many reasons why folks shouldn't equate exotic pressure related terms like +P and +P+ with projectile performance. The P designations are relative to PEAK pressure and not total pressure.

The sound and the fury.
FLASH
CRACK
30 carbine, short barrel, indoor range.

Sam

 

[Carbon_15]

You really want to get everyones attention in a hurry? Take a Carbon-15 pistol (7.25inch barrel) and a few boxes or PMC .223 ammo to an indoor range. Even from my pre-ban AR with the bird cage flash hider that ammo makes basketball sized fireballs. From the pistol its just amazing.


The picture below is of a buddy of mine shooting the PMC stuff from my C-15 Type 97 rifle w/ the factory muzzle brake attached.

 

[22lovr]

Carbon15: unreal!

You know, Carbon15, an image like that just gives me the heebeejeebees. I mean, we're all holding little controlled BOMBS in our hands! What a marvelous technology.

My mod 605 has a cylinder gap of approx .004-.005 and, still, the gap flash mushroomed out to what appeared to be the edges of my shooting stall!

When I'm shooting Georgia Arms through my Smith mod 638, the 158 gr swc's have very little muzzle flash, the 125 gr JHP + P's a little more and the 110 gr gold dot JHP + P's really light the place up. I would assume from what I've observed, the heavier bullets allow more complete combustion of powders before exiting the barrel, while the lighter bullets leave quickly, followed by still-igniting combustibles.