Quite the fireball

[wyrmzr]

I ran out of H322 the other day, and finally had to break open the only rifle powder I had, which was H335. Is this an indication I could run slightly less powder? It was just over the recommended minimum, 21.5 grains behind a 55 grain FMJ. I'm not used to seeing the fireball flash in my scope with the H322.

[Garyshome]

Almost as good as the mosin?

[wyrmzr]

Funny thing is, it's been so long since I fired a factory/surplus round in my 91/30, I don't remember what the fireball is like with them. Here's one of my 91/30 cast handloads, 20g of IMR 4227:

[Multigunner]

This reminds me of some questions asked on a Indy film forum.

A film maker was trying to film a night time gun battle scene and was using a Mosin Nagant short rifle to supply the muzzle blasts to be edited into the video.
Problem was that one out of three shots gave a terrific visible muzzle flash while the blasts of the rest of the shots were not visible when the tape was played back.
I could not figure that one out. If it had been a film camera I'd have figured the indiviual frame exposure time was too short.
He said the ammo all came from the same box but had not saved the empties to check the headstamp.

Any ideas on what caused this?

[Frank46]

Not really, I have a MN M44 carbine and you can count on a fireball with each shot. I'm using yugo heavy ball the stuff that came in the NNY or PPU boxes. There was a bunch imported some years back, if you see some grab it. Very accurate in the carbine. I didn't notice the fireballs at first but a buddy wanted to shoot it and I stood off to the side. Youzers flame broiled hot dogs. Frank

[Linstrum]

Could be that when the flash occurred the movie camera shutter was between exposures. If it wasn't camera-related then the only possible explanation is that some of the ammo in the supply was not loaded with powder that flashed brightly. Most common U.S.-made military rifle powders have flash suppressant additives since bright flashes on the battlefield can give away a soldier's position, and some like IMR7383 are designed to be flashless. Pistol and shot shell powders like Unique and Bullseye that have been manufactured for over 110 years now put out a pretty good flash. A lot of Russian powders make bright flashes. I don't know about Chinese powders in general. Ammonpulver, the first modern smokeless powder, is also flashless as well as totally smokeless since its combustion products are water, carbon dioxide, and nitrogen that are all clear and colorless.
rl 1,186

[Ricochet]

I remember reading 40 years or so ago in a Lyman reloading manual that a brilliant muzzle flash with ball powders often is a sign that the load is light. Presumably because it burns more slowly in the light load, keeping the gas temperature up at the muzzle so it's more likely to ignite when it contacts the outside air. Muzzle flash is an interesting phenomenon. There's a primary muzzle flash from the hot powder gas, which has cooled from expansion by the time it reaches the muzzle so we don't see the full white heat of its burning but a red or orange squirt out of the muzzle. Not too impressive. But there are a lot of combustible gases in powder smoke. Nitrocellulose burns "rich" and puts out some carbon monoxide and hydrogen. Powders contain lots of other organic materials, residual solvents, deterrents like the dibutyl phthalate used on many ball powders, plasticizers or "colloiding agents," and diphenylamine stabilizer. There's enough of these things in some powders that they're only around 70% nitrocellulose. All of these substances vaporize in the heat of the powder burning, and become gaseous fuels with no oxygen available to burn them. If they come out hot enough, and/or there are live sparks for an ignition source, they will mix with air outside the muzzle and burn brightly, creating a secondary muzzle flash. They may not always ignite, though, and all you see is the dull red primary flash. Flash suppressors may work by keeping the gas from mixing with air until it's cooled enough from expansion to be unlikely to ignite, as the old conical flash hiders. Or they break up the gas into lots of small jets or sheets of gas that cool very rapidly before they can ignite. Powders may have small amounts of chemicals like potassium salts added, that act rather like antiknock additives in gasoline to delay ignition until the gas has cooled too much to ignite, or they may have enough volatile organic stuff added to cool the combustion enough to prevent secondary ignition. Artillery propellants often contain inherently low flashing energetic substances like nitroguanidine. Most of the time I love a good bright muzzle flash. Adds fireworks to the fun. That's one reason I love ball powders.

[Mk42gunner]

Every gunnery school for small arms I ever went to said the flash suppressor wasn't to hide the fireball from the enemy, it was to keep it from blinding the shooter. Thankfully I never had to experience incoming or outgoing small arms fire to verify this. Outgoing 5" yes, but it is kind of hard to hide four destroyers on the gunline anyway.

To wyrmzr, H335 is slower burning than H322, makes sense to me that it will throw a noticeably bigger fireball from short barrels, especially if they don't have a flash suppressor to help break up said fireball.

Robert

[303Guy]

That's interesting Ricochet, many thanks.

I've often wondered just how much oxygen is released in powders and considered the possibility of them being rich if for no other reason than to keep temperatures down. But what got me wondering was the question of what happens if there is oil trapped between the case and chamber. I speculate that the oil will get finely atomized into the throat behind the bullet and burn in the available oxygen, resulting in pressure excursions. Mind you, the vaporized oil would add to the volume and hence pressure even if it did not burn.

[GabbyM]

Is that a 16 inch barrel?

You will get better burn and lower E.S. with a magnum primer with H335 in the 223 rem. CCI Magnum or the #41 military primer. DITTO on MK42guners post.

I stay with 20" barrels on my AR-15"s. In part because of the muzzle blast with short barrels. Last year I picked up a 222 Rem bolt gun that I highly favor. For a walk about varmint rifle. Anything that may be shot without hearing protection at times. Doesn't look like much on paper but the 222 is far more pleasant to shoot than a 223. Even my 26" barrel varmint rig in 223. Ballistics of my 24 inch barrel CZ-527 LUX will match or out run a 20 inch barrel 223 AR-15. With cast boolits it will keep holes near touching at 100 yards. Off a bench more bullets will touch than wont. It's 110 yards across the grass between fields at the home place. So once you get a rifle off the sand bags the boolits shoot well enough to leave the rest up to the shooter. Our land runs uphill from the house for 200 yards then falls off. We have a 5 foot tall fence post half way across the quarter mile property line so we can plow a straight line over the hill. So a 200 yard cast boolit shooting 222 really does cover anything you can see while your feet are on the ground.

Not that my fondness for the little 222 kept me from spending $1,500 or so last month on parts for AR-15's. Like an ACOG for 24 hour shooting and a Criterion Barrel for my almost done SP-1 tube.

[Lead Fred]

Smith Enterprise's flash hider will snuff that flame

[wyrmzr]

Yes, that's a 16" bull barrel. The lack of a flash suppressor, plus the large diameter of the barrel, makes it look shorter than it is. I hadn't noticed the flash from my other rifles, but seeing this through the scope was an eye opener.
It could suck during night time hunting for coyotes, so I'll either have to switch barrels for that, as adding a flash hider to that bull barrel would, I'd think, be a pain.

[Garyshome]

Sorry I didn't mean to hijack your ar thread!

[GabbyM]

I'd not worry about that flash to much. Until you try shooting it in pitch dark after your eyes have adjusted . It may not be as bright as it looks on the video.
I don’t know if a magnum primer would cut flash any. It certainly wouldn’t be by much.
I do know most shooters have better luck lighting H-335 with a magnum primer. My records show Federal 205 Match with a 55 rain bullet gave me an E.S. of 80 fps and %SD of 80. Fed match are very mild primers so standard primers from other brands may work a little better.

[Ricochet]

Video cameras tend to be sensitive to near infrared. Makes the flash look brighter.

[Luigi Lavazza]

Fireball from my M48 with a cast load:

[Cmm_3940]

My experience, 55gr FMJ, 25gr H335, 16" bbl. + flash hider. Never notice any flash unless it is getting dark out. You can try using magnum primers as is often suggested for H335, but I have never noticed a difference in accuracy, so I don't bother keeping another primer type around.

unless the flash bothers you, I wouldn't worry about it.

[Cmm_3940]

Fireball from my M48 with a cast load:

Cool photo!

[Possumcop]

I've noticed that my .223 loads with H322 seem to have less flash than any of the other "full power" loads I shoot.

In 7.62x39, the H322 seems to put out MORE flash than most of the other powders I've used.

Kinda strange, but maybe it's because it's a pretty fast powder for .223 and considered slow for 7.62x39.