% of powder burned up

[CS86]

How does a person figure out how much powder is burned up once you fire the bullet with a given barrel length? Is there a formula or way of testing?

[amamnn]

if you are asking out of idle curiosity--the answer is--it does not signify much--if you REALLY must know--or at least get a pretty good idea-- you should buy Quickload, as long as you have other uses for the program as well...................

http://www.neconos.com/details.htm

[wncchester]

After 47 years of reloading this is the first time I've ever seen that raised as an issue.

[Brian Pfleuger]

QuickLoad is the only way I know of to get an approximate answer to that question. QuickLoad is a fantastic tool for the reloader, albeit with a bit of a steep learning curve.

As to the question being raised, it does have it's usefullness. For instance, % of power burned has a direct affect on muzzle pressure. Muzzle pressure can have a dramatic affect on recoil and is directly responsible for muzzle blast.

I used QuickLoad specifically to choose a powder for my Encore 7mm-08 with a 15" barrel that would maximize velocity and minimize muzzle pressure. Generally, that means a fast(er) burning powder but it's not a direct correlation, neccesarily. Without QuickLoad, it's just a guessing game.

The difference between a powder with high muzzle pressure (H380) and low(er) muzzle pressure (IMR3031) is dramatic in terms of recoil. Percentage of powder burned is a big factor.

With QuickLoad, at least you have "theory" rather than speculation.

[CS86]

if you are asking out of idle curiosity

There is some curiosity. It makes me wonder how much powder gets pushed out the end of the barrel and more or less wasted. What made me think of the question was I was shooting a 9mm Hi point carbine and I would find unburned flakes of powder on my table after shooting.

With the carbine, using blue dot, I played with the COAL and stepped the powder. My best loads so far was with 124 HP Berry's had a COAL of 1.085 with 6.3-6.7gr of blue dot. I had tried some rounds with 7 gr which was a slightly compressed load. It started showing small signs of pressure and my group opened way up. Then it made me wonder with a bullet designed for a pistol how much powder is too little and how much is to much for a slower burning powder. How much is maybe wasted with slower burning powders with this type of gun and other rifles.

I'd like to try a shorter coal that works in my Springfield XDM, but the bullets only allows me to 1.049 reaching the lands and I don't think I even want to attempt to go that short. I don't know if I would even have enough powder after going that short to work in my carbine.

After 47 years of reloading this is the first time I've ever seen that raised as an issue.

Leave it to the newbie.

As to the question being raised, it does have it's usefullness. For instance, % of power burned has a direct affect on muzzle pressure. Muzzle pressure can have a dramatic affect on recoil and is directly responsible for muzzle blast.

After thinking about it for the Carbine I also wondered about other rifles and how it would maybe effect the muzzle pressure. I kind of figure if you are pushing lots of unburnt powder out of the barrel maybe you should try a faster burning powder. Seems like a waste of money.

[CherokeeT]

Why not shorter ? Just reduce the charge a little and work up in the carbine and the XDm. I like HS6 and power pistol in the 9mm but PP has lots of flash and bang.

[briandg]

Unless there is some fundamental problem with your load, you should never find more than an occasional flake of undamaged powder. Exceptions would include extremely slow starting ball powders, and very short barrels.

The charge in any good round should be fully ignited by the time the bullet is through the forcing cone/barrel leades. You do lose a great deal of energy, energy that would be propelling the bullet.

In a perfect world, the curve would be reversed. Pressure would build as the bullet approached the end of the barrel rather than spiking just as the bullet enters the barrel.

Slower burrning rates allow pressure to remain high farther down the barrel. This allows for greater accelleration; greater acceleration results in higher velocity at the muzzle.

[Jimro]

The charge in any good round should be fully ignited by the time the bullet is through the forcing cone/barrel leades. You do lose a great deal of energy, energy that would be propelling the bullet.

Like any statement, there are exceptions.

How powder burns in the brass is a very interesting subject. With frontal ignition we know that the powder column starts burns front to back and as a result the brass is much hotter than standard ignition rounds.

I think one of the reasons that stick powders have a better reputation for accuracy (backed by testing) is that there is more room between individual kernels for the primer flame to shoot through the powder column. With ball powders the spaces are finer, the primer flame has less space to move through and so the conventional wisdom is to use magnum primers to get consistent ignition.

With a standard milspec M80 ball load it takes 18 inches of barrel to 100% powder burn. For a while folks noticed that sealed milsurp 45 ACP ammo had more consistent velocities as the tar sealant held the bullet into the brass allowing more time for proper ignition to take place.

Jimro

[briandg]

This question is really in my thoughts completely irrelevant.

Do you want consistency of velocity? buy a chronograph. Do you want higher velocity? buy a chronograph. Do you want accuracy? shoot at paper. do you want power? buy the chronograph and do the math. Afraid of pressures? stay within loading recommendations and pay attention to pressure signs and details.

What are you wanting to know, that can only be discovered by learning how much energy is ejected out the barrel unburned?

Buy a chronograph, look at your results, and either be happy with what results you have, or try to find better. results are what matters, and none of the impossible to determine esoteric statistics can matter more than those results.

[Brian Pfleuger]

Originally Posted by briandg

This question is really in my thoughts completely irrelevant.

Do you want consistency of velocity? buy a chronograph. Do you want higher velocity? buy a chronograph. Do you want accuracy? shoot at paper. do you want power? buy the chronograph and do the math. Afraid of pressures? stay within loading recommendations and pay attention to pressure signs and details.

What are you wanting to know, that can only be discovered by learning how much energy is ejected out the barrel unburned?

Buy a chronograph, look at your results, and either be happy with what results you have, or try to find better. results are what matters, and none of the impossible to determine esoteric statistics can matter more than those results.

As I noted before, muzzle pressure is directly affected by % powder burn. Muzzle pressure affects recoil, sometimes dramatically. So, knowing both can help you choose a better powder, one that will do the same job with less recoil. Muzzle blast, another corollary of muzzle pressure, can affect accuracy. The bullet is IN that blast for a brief moment and less blast might make for more accuracy. Less muzzle blast is also more pleasant on even protected ears and certainly for bystanders.

Plus, two loads might produce similar accuracy and velocity but one is burning 85% the other 96%, why throw away 11% of your powder?

[Mike Irwin]

"The charge in any good round should be fully ignited by the time the bullet is through the forcing cone/barrel leades."


I can't remember whether it was William C. Davis or Ed Matunas, writing in American Rifleman many years ago, who said that, possibly with the exception of .22 Long Rifle in a long-barreled target type rifle, NO cartridge will burn all of its powder fully and that a surprising amount will be ejected out the barrel.

That's just the nature of the beast.

When I worked for Rifleman we tested handgun and rifle rounds of all stripes, from the tiny to the enormous. After a shooting session indoors across the chronograph it was surprising how much unburned powder we would sweep up.

Even what at that time was considered to be among the most efficient cartridges available, the 6mm PPC, would leave unburned powder on the range.

Later, when I worked at the shooting range, we would occasionally have "range fires" where unburned powder on the range floor ahead of the firing points would ignite and burn. It was always a peculiar sight to see.

[briandg]

fully ignited doesn't mean fully burned. an old guy once told me that learning my KY rifles maximum charge was simple. increase the powder charge 5 grains at a time, and shoot over a sheet of newspaper. when it starts spitting out a lot of unburned granules, youve passed maximum.The charge burns completely from the back. when it no longer has muzzle time for the flame front to reach the front of the charge, that is maximum.


Once again, using empirical observations of muzzle blast, muzzle flask, felt recoil, etc, will be far superior than trying to extrapolate these hard to predict properties from a factor that can only be semiaccurately represented by powder analysis.

The most accurate way to measure any of the things you mentioned is by direct observation, not prediction. Observe, learn, adapt until you reach success. Maybe that's too old fashioned now.

[Brian Pfleuger]

Using subjective criteria like muzzle blast and recoil is superior to computer analysis that has been and can be proven accurate?

Interesting.

Besides which, even if it were (which I highly doubt), why would someone want to buy several pounds of various powders and all the necessary other components rather than using a computer to predict the one or two best options and starting there?

[briandg]

Using subjective criteria like muzzle blast and recoil is superior to computer analysis that has been and can be proven accurate?

Seriously, this has to be a joke.

When you fire two different loads from a pistol, and you perceive one to have higher recoil or muzzle blast, you will still take the data from the computer and presume that it is right, and assume that your objective expereince and observation was wrong?

If computer technology is how you choose to reach the end of the process, that is your prerogative. There are alternatives. By your own admission, you don't need those alternatives, because you want hard predictive data, instead of objectively observeable results to work with.

[Brian Pfleuger]

Originally Posted by briandg

Seriously, this has to be a joke.

When you fire two different loads from a pistol, and you perceive one to have higher recoil or muzzle blast, you will still take the data from the computer and presume that it is right, and assume that your objective expereince and observation was wrong?

If computer technology is how you choose to reach the end of the process, that is your prerogative. There are alternatives. By your own admission, you don't need those alternatives, because you want hard predictive data, instead of objectively observeable results to work with.

You probably won't disagree with QuickLoad though.

I know what QuickLoad can do. I asked it what powder would create the lowest muzzle pressure with an acceptable pressure and velocity and I bought the powder it suggested. Since I already had a powder that it predicted would create MUCH higher muzzle pressure (50% higher) and recoil at the same velocity, I tried that one too.

It was right. I didn't need to waste product finding out. The difference is dramatic and unmistakable. I would have found the same thing by myself.... eventually. I'm sure I would have wasted FAR more money than QuickLoad cost and certainly far more time.

[briandg]

I'm going to defer to your far greater knowledge and experience in this area. You've worked with it. you believe in it. I may find it to have less value than you do, but that's my take on it, and you obviously take your reloading far more seriously.

[davery25]

todays camera can record at super fast frame rates. set up your camera next to the muzzle. Slow down the vid and start counting!