complete powder consumption for reduced muzzle flash

[cpileri]

Learned Sirs and Ma'ams,
Is there any way to predict or calculate what loads and of what powder will burn 100% in a given barrel length?
Or, is there any extensive source for this info, even if derived experimentally?
 
I will be taking care of some predating coyotes in the evening/dark, and will be using an 8mm Mauser sporter carbine; that has a night vision scope on it.  I want to keep the flash to a minimum so that the scope dimming is not too limiting (or if it can be eliminated...)
 
The rifle has no flash hider, and no threaded barrel; and I dont want to go that route- esp if I can achieve it with proper load data.
 
I know that I can use "the Load" (13gr Red Dot and normal-for-caliber-weight cast bullets) and other reduced loads using fast powders.  I will use these loads only if a load that approximates full power, range, and trajectory cannot be achieved with complete powder burn.
 
Many Thanks,
C-
 

[tacklebury]

There is, but I am not in the know on the calculations manually.  My buddy has a copy of Quickload II software and it will tell you % of burn for a given barrel length.  My personal findings are that sticking to the faster burn rate powders like the Dots and Unique are a good way to minimize flash signature even in big bores.  You do have to be careful to avoid double charges etc.  I use 11 gr. Unique in my .45-70 with a 157gr. RB for light varmint loads.  Sometimes you can post a given load and get someone online to do the quickload roll up to get that data.  Might wait to see. 

[cpileri]

That Quickload program sounds pretty cool!
Any idea how i shoudl phrase the question so the program can work with it?  What i mean is,
would it be able to tell me an answer in a question phrased with barrel length the variable, or with powder charge the variable?  or something else?
examples: 
Multiple-Powder charge variable: With 8mm Mauser chambering and 200gr projectile, and 20" .323 barrel, how much of each powder gives 100% burn?
 
Single Powder charge variable: With 8mm Mauser chambering and 200gr projectile, and 20" .323 barrel, how much of IMR-4895 gives 100% burn?
 
Barrel length variable: With 8mm Mauser chambering and 200gr projectile, and 45gr of IMR-4895, how long a .323 barrel is needed to give 100% burn?
 
That quickload program comes up alot.  Is it worth the cost?
 
C-
 
 
 

[tacklebury]

Here's the link to their website: http://www.neconos.com/details3.htm
 
I usually tell him the case I'm loading, the bullet I'm loading, the charge I'm looking to start at and barrel length.  From this we start playing with charges and getting % efficiency and burn ratio.  He just keeps bumping up the numbers until we hit SAAMI pressure limits, case capacity limits or speed we're going for.  hehe 

[davem270win]

Hmmm, my understanding is that all of the powder has "burned" within 2 - 3 inches of bullet travel, no matter what powder/caliber/ etc you're using. The muzzle flash is a byproduct of the hot gases reacting with oxygen after leaving the confines of the barrel, and that certain powders (like BLC2) create more flash than others.

[SHOOTALL]

I doubt that is true , as often un burned powder is released as the bullet leaves the bbl. Also the shorter the bbl the more flash leading one to believe more powder to burn out side the bbl. Some powders are treated so they flash less maybe you could find out which ones.

[charles p]

I don't have any evidence for or against the assumption of where powder is burned.  One thought on the topic is:  If only so much powder can burn in the barrel and the rest is burned beyond the barrel, why will a double charge cause a pistol barrel to explode?  Why do rifle cases seperate and barrels bulge or fail if excess powder is burning outside the barrel?
 
Exception might be black powder.  I've seen unburned black powder.

[SHOOTALL]

Good ? First what happens when a round is firred ? The powder starts to burn and it has its first pressure peak when the bullet starts to move out of the case. It has a second peak as the bullet engauges the rifling and a third when powder is either burned completly or bulet exits the bbl. So if you use enough powder to only burn part way down the bbl in reality the rest of the trip down the bbl is doing more harm to velosity than good . As to the ? of burst bbls. Most loads are a safe load. It is figured on case capacity and powder used ( Much more goes into it but we are talking powder here) . So if you over load or double load a case you cut the room for the powder to expand  and added more burn raising the pressure peaks to a point the bbl will fail. You might think the bullet would move on faster but if pressure builds faster than the bullet can move thru its peaks pressure will rise to dangerous levels. When a bbl is obstructed the space between the bullet and obstruction will build fast enough to burst a bbl when many times you can blow out the dirt or snow with your own breath . But the pressure builds to fast and the bbl burst when fired.
Some think the unburned power is waste but its volume adds to the safe pressure and gives more velosity. My point above is there are so many powders aval with so many burn rates it would be impossible if all burned in 5-6 inches of bbl. Just charge weights alone would vary the length of burn. Note that shape and coating determins burn rate and some coatings effect flash. Most 40 S&W factory ammo shows less flash because it was a new round and powders were developed for it.

[AtlLaw]

It seems everyone is assuming that muzzle flash is caused by unburned powder igniting outside the barrel.     That got me to thinking... 
 
One of the ol' timey ways of determining the max amount of black powder (BP) your particular rifle could burn in it's barrel was to keep increasing your load until unburned granules of powder could be seen in the snow.
 
Now if that was true, and unburned BP could be ejected from a barrel and land on the ground when the rifle was fired, that would mean it wasn't ignited by the discharge.
 
When I consider that BP is an explosive and much easier to ignite then smokeless powder, I wonder, can there be a factor other then unburned powder igniting outside the barrel involved in the creation of muzzle flash?   
 
Oh, BTW, I always accepted the often made statement that all the propellant is burned up within the first few inches of the barrel.  Now y'all got me wondering... 

[SHOOTALL]

Some have taken a 308 rifle with a 26 inch bbl and cut off 1 inch sections until velosity declined . 20 inches was the length where velosity started to fall. They used Federal ammo. Shot 8-10 rounds with each bbl length. Google it and read for yourself .

[charles p]

I think the powder in a shotgun shell is quickly burned, before the shot charge goes very far.  Not too sure about pistol or rifle charges.  Just don't know.
 
With the very slowest rifle powders, an "over max" charge could be less dangerous than with fast powders like shotgun and pistol loads are designed for.  I know for a fact that you can not overcharge a 300WIn case with H-4831 because a friend of mine used to fill his to the top, then seat the bullet.  He is still with us today.  He shot 150 grain bullets.  A 220 grain might have made a big difference, assuming he could seat the bullet deep enough to chamber in his 700.  DO NOT TAKE THIS AS A RECOMMENDATION!

[mdi]

http://www.navweaps.com/index_tech/tech-090.htm Interesting article on muzzle flash. I too believe it's combustable gasses reigniting as the gasses exit the muzzle and come in contact with oxygen rich air...

[AtlLaw]

Thanks mdi!      That's what I was thinking of!  Now I can go back to where I was, comfortable with the concept that the propellant is all gone (only the expanding gasses remain) before the bullet leaves the barrel.

[MZ5]

Smokeless powder does not contain enough oxygen to completely oxidize all the fuel in it, so it flashes when it gets fresh air.  Accordingly, I recommend a flash-deterred/flash-suppressed powder. It's the only way you're going to get what you want.

I recommend calling the powder suppliers to ask them about flash deterrents in rifle powders.  I _thought_ TAC was flash-deterred, but it may not be.  I'm more familiar with flash reducers in pistol powders.

[tacklebury]

Sorry guys, but if I shoot a heavy Reloader7 (slow powder) load from my 5.5" Blackhawk, you get about a 3 foot long fireball...  If I shoot the same load from a 14" Contender, I get a very short fireball and if I shoot it in my 20" colt carbine, I get zero fireball...  Powder is consumed at a fixed rate depending on it's burn rate and that's why there's a chart and % of burn rate in Quickload and similar programs.  Powder by default has an OXIDIZER in it that creates it's own oxygen.  It doesn't need oxygen to ignite, because it makes the oxygen.  Otherwise the TINY amount of air in a compressed load wouldn't be enough to even start the combustion!  All powder needs is heat to begin the process which then forms oxygen as the oxidizer breaks down.  In black powder the oxidizer is Potassium Nitrate.  Nitrates are oxidizers by default. 

[SHOOTALL]

I think the powder in a shotgun shell is quickly burned, before the shot charge goes very far.  Not too sure about pistol or rifle charges.  Just don't know.

From what I have read it takes about 12 to 16 inches of bbl depending on powder type and load.

[MZ5]

Powder by default has an OXIDIZER in it that creates it's own oxygen.  It doesn't need oxygen to ignite, because it makes the oxygen.

Well, it doesn't "make" oxygen since there are no thermonuclear reactions going on in our firearms.  Just funnin' with ya!     An oxidizer is an ingredient that contains excess oxygen.
 
Let me be more specific, since I generalized incorrectly:
Nitrocellulose does not contain sufficient oxygen for complete thermal decomposition.  Nitroglycerine does, and in fact contains excess oxygen.  IOW, nitroglycerine is an oxidizer.
 
So, then, single-base powder is at an oxygen deficit, and will scavenge oxygen in free air if/when it becomes available.  Double-base powders shouldn't need to do that (scavenge oxygen), although interestingly double-base propellants are noted in at least some references as being more susceptible to muzzle flash.  Nitroguanidine (the third 'base' in triple-base powders) is specifically called out as useful for reducing/eliminating flash.  I can't think of any civilian triple-base powders off-hand, can you?

Here are a couple quick references for those who are interested:
http://books.google.com/books?id=stoY55Kj7wUC&pg=PA138&lpg=PA138&dq=does+smokeless+powder+have+sufficient+oxygen+for+complete+combustion?&source=bl&ots=jHGaDWnrUn&sig=tKKZNocUEkxW7vDwRd6CuiA83Z0&hl=en&sa=X&ei=F6QiT_GbBaGhiQLNlfmBCA&ved=0CDoQ6AEwBw#v=onepage&q=does%20smokeless%20powder%20have%20sufficient%20oxygen%20for%20complete%20combustion%3F&f=false
 
http://books.google.com/books?id=rqZROysoS7QC&pg=PA214&dq=is+nitroguanidine+an+oxidizer?&hl=en&sa=X&ei=bagiT_-OBeXMiQLYmpH5Bw&ved=0CDkQ6AEwAQ#v=onepage&q=is%20nitroguanidine%20an%20oxidizer%3F&f=true

[MZ5]

Perhaps it's worth adding that the scavenging of free oxygen doesn't _have_ to always result in a bright flash, nor even happen.  Whether it does may depend on a number of things, one of which is gas temp once it clears the barrel.

[AtlLaw]

Sorry guys, but if I shoot a heavy Reloader7 (slow powder) load from my 5.5" Blackhawk, you get about a 3 foot long fireball...  If I shoot the same load from a 14" Contender, I get a very short fireball and if I shoot it in my 20" colt carbine, I get zero fireball...

I'm kinda confused there Tack...    Happens a lot the older I get.   
 
Anyway, are you saying the longer the barrel the shorter the fireball phenomenon is caused by more of the propellant being consumed by the longer barrel, and so there is less powder to ignite outside the barrel, hence the smaller the flash?   
 

Powder is consumed at a fixed rate depending on it's burn rate

Without question
 

that's why there's a chart and % of burn rate in Quickload and similar programs.

I know nothing (I sound like Sgt. Schultz!    ) about that % of burn (I'm assuming it is % of propellant consumed) in Quickload; I need to research that issue.     But, it would be interesting to see what the percentages are for Reloader 7 out of your 3 barrel lengths.  If it shows a lot of unconsumed powder out of the short barrel and no powder unconsumed out of the carbine barrel, that would be pretty darn conclusive evidence in favor of your position!   
 
It would also interject another factor into load development that hasn't been a major factor since the introduction of smokeless powder; barrel length!  I mean, why would you even want to develop a load around a powder that wouldn't be totally consumed in the barrel of the weapon it was fired in?  After all, it is the expanding gases that propell the bullet, not ejecta!   

[SHOOTALL]

So do Glocks have Flash when shooting under water ? 

[AtlLaw]

 

[tacklebury]

So do Glocks have Flash when shooting under water ? 

I haven't personally had the opportunity to review the firing of a glock underwater, but I know that the fact that a firearm can fire under water, ie. an MP-5 in the hands of a Navy Seal, means that the powder produces all the oxygen that's needed to sustain it's ignition.  I'd say tenatively, yes the same flash bubble would be produced, but it'd be interesting to see in slow video if someone has that capability.    Also, solid missile firing packs to get from the tube of a submarine to the surface work the same way.  Their oxidizer produces the O2 needed to sustain the missile until it clears the water, then the liquid fuel, ie. jet engine, takes over. 

[cpileri]

I must thank all the replying members, and say that I am very much enjoying this thread.  The subject in general, even though my question was about a specific issue, is interesting to me.
 
I have a question about plasma physics: if the fuel (powder) is fully consumed in the barrel, so that only the bullet and hot speeding gas contacts the oxygen/air at the muzzle, what is causing the flash? no powder remains to be burned? is the oxygen-becoming-plasma a source of visible light?
 
Anyway, still working on my original problem, but reading and enjoying nonetheless.
 
And I want to see a video of the flash if any of a glock underwater too!
 
C-

[MZ5]

Powder is consumed at a fixed rate depending on it's burn rate

Without question

...which burn rate is highly pressure-dependent.  You two are speaking in that context?

[AtlLaw]

...which burn rate is highly pressure-dependent.

Without question!   
 
Ya know, I've been doing a little reading on this, and while I still believe most muzzle flash is the result of propellant gases reigniting, I'm also starting to think that it is possible that unburnt powder can be ejected from a barrel.
 
I mean, like, you know, how cool is that!   

[MZ5]

I mean, like, you know, how cool is that!   

Werd!
 

[SHOOTALL]

Well if you have ever shot a rifle ir hangun over the hood of a truck as we do often while groundhog hunting etc. you will notice (depending on load ) unburnt powder on the hood after firing along with specks I assume from the powder that did burn. I can only guess why there is unburned powder , I would exoect that leaving the bbl at over 3000 FPS some powder out runs the fire ball that exits the bbl and is to far to be ignited . Some pcs of it have plat sides and spots again I assume from rubbing the bbl on the trip out the bore.