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Joined: 03 Feb 2008 Posts: 830 Location: Adirondak Mtns

I have over 500 Federal Game load hulls that I would like to have a good 7/8 oz load for. I currently load Multi-Hulls with Solo 1250 at 22.5 Gr. using the BP SG16 wad with an overshot card. The BP manual shows this being about 8000 PSI. It works well on birds and clays and has less recoil than the Fed or Rem Game loads.

Does any one have load data for the Federal hull at 7/8 oz that would be comperable??

Thanks

Joe

Guest

Joe the Mulit hull is a Cheddite or Cheddite clone hull which has the same interior volume and geometry as the Federal hull. With a chamber pressure at 8000 psi I would use the same load that you are using in the Multi hull in the Federal hulls.

It would be interesting to send three of each load to Tom Armbrust to see how accurate the BP data is.

Joined: 03 Feb 2008 Posts: 830 Location: Adirondak Mtns

I had measured the two cases saw that the were nearly identical volume wise. But I am new to shot shell reloading and want to proceed with caution.

I'll Try the load and if you have an address I will send the shel for testing. What is involved and what is the turn arround time?

Thanks

Joe

The Federal hulls have a rolled paper base wad. The Cheddite and Fiocchi hulls have a plastic base wad. All other things being equal, using Federal hulls will generate a bit less pressure. However, this should not prove to be significant unless your recipe is near or at max pressure already. But keep it in mind for future reference just to be safe.

Guest

jswanson,

A popular notion is that you can measure case volume between shotshell sand as long as the volume is the same you can use the same data.

Absolutely incorrect. The internal shape of the hull has a large influence over how quickly the powder develops max pressure.

Shotshells are a completely different animal than rifle cases.

Federal 16 gauge hulls, with some loads, develop significantly more pressure than SOME of their plastic basewad counterparts.

Joined: 06 Mar 2008 Posts: 596 Location: 17603

"he internal shape of the hull has a large influence over how quickly the powder develops max pressure."

Mark,
So the shape/profile of the basewad can affect burn rates? Guessing here that the cone shape of the Federal paper base wad versus the flat cup seen in the Cheddite causes the difference, and of course that's the powder sitting right over the primer. Innerestin'!
Cheers,
Rich

Guest

Rich,

It changes the time / pressure curve for sure. The positioning of the primer has an effect also, in terms of how much of the powder is exposed to the hot particles as the primer is ignited.

Kinda why sweeping statements and rules of thumb should be left out of shotshell ballistics. The only constant is that there aren't any constants.

Without getting lengthy, you can't change the burn rate of the powder The 'burn rate' is determined by the deterent coating, chemical make up, and the size and shape of the powder kernels.

Joined: 06 Mar 2008 Posts: 596 Location: 17603

Mark,
Right, can't change the "burn rate", but how it's ignited, and how much initially is exposed to the primer flash changes the overall combustion curve, with subsequent changes in pressure characteristics.
Cheers,
Rich

Guest

Member Joined: 02 Oct 2007 Posts: 1975

Guest

I wish folks here could sit down and talk with folks like Dick Quesenberry of Hercules/Alliant. He was one of the men in the ballistics lab in Va for years. I learned quite a bit from him and his staff. Their take on this subject is where I learned some of my shotshell reloading ABC's. (I'd been packing rifle loads with smokeless propellants for some time before this without hurting myself too badly Wink

.)

Dick helped me develop my own 1 ounce 28 gauge magnum load using 2400 as the propellant. It was my first venture into "no man's land." Dick was kind enough to have the loads tested for pressure to keep me from blowing my fool head off. Laughing

His advice on the subject to me pretty much agrees with spr310 here. In fact, the advice is almost verbatum.

Dick stated that as pressure increases, so does the rate at which modern smokeless propellants combust and vice versa. Knowing this allows us to manipulate the rate of combustion to our advantage.

Of course, this does not imply that we are changing the chemical make up of the propellant, its grain size and shape, or any of the retardants and other coating used to determine and control its intrinsic, designed combustion rate class. Only the manufacturer can do this. So the intrinsic burning rate class of the powder is determined by how it is made and the burn rate class is fixed.

All that this tells us is that one powder will almost always burn faster or slower than another with a different makeup if the conditions are identical. This is why a controllable closed bomb test is used to determine how closely the burn rate of one batch of a particular powder matches the manufacture's standard. If it is within a certain acceptable range, it can be then classified as canister grade. If it is within a slightly wider range and remains within acceptable limits, it can be sold as bulk powder to munitions manufactures who will then determine the exact charge amount they will need to obtain a standard velocity class for the ammo they wish to manufacture. (This is why cutting a shell open to find out the type and amount of powder being loaded is a bit risky. That particular powder is probably not canister grade.)

If we change the conditions inside the shell, we can change the resulting combustion rate to some degree. Of course, we can't can change the rate of combustion once the primer goes off. We can control some of the variables that will determine the general burning characteristics of the propellant in that particular load and we can manipulate resulting pressure curve to our advantage.

Initial conditions inside the combustion chamber do help determine how well the burning process gets started and will help determine the elapsed time to peak pressure. So does primer brisance and duration of the flame, and the initial resistance of the ejecta including the resistance of the crimp, the shape of the wad, and the condition of the hull walls. These factors all work together.

The above also helps explain why shotgun ballistics is not as an exact science as rifle or pistol reloading ballistics. There are simply more variables at work, and they are harder to control.

Since Dick was one of my tutors, I will still follow his teaching. I'm not trying to wage war here. I simply think my input has some value. It is based on the knowledge of a man far more experienced than I am on the subject. Dick's advice to me is based on the knowledge of his uinstructors. I've seen much the same information in any number of reloading manuals on the subject of smokeless powder and how it burns.

Anyone is certainly entitled to disagree. However, I'd appreciate it we can all do so in the form of an impersonal post stating tha facts as we know them or believe them to be. I think we need to step back from the "Hey fella, that is pure bullshit" type retorts that have been becoming so prevelant around here lately. Lets get back to being gentlemen again. For those of you who have remained gentlemen all along, I beg your understanding, your indulgance, and your pardon here. I also thank you.

Joined: 06 Mar 2008 Posts: 596 Location: 17603

"Initial conditions inside the combustion chamber do help determine how well the burning process gets started and will help determine the elapsed time to peak pressure."

That's my understanding from what dogchaser pointed out, we may be quibbling about the definition of "burn rate", which IS controlled at manufacture, granule size, coatings, nitroglycerin content in double base powders, etc., fast vs slow powders. His point I believe is that the shape of the combustion chamber, ie. a different base wad in this instance, can change overall pressure, even though other variables, such as case capacity, may be the same. That was news to me.
Cheers,
R*2

Guest

Then why don't we try to manipulate the following recipe, using Red Dot in a Winchester 16 gauge compression formed hull, a Winchester 209 primer, Remington SP16 wad, and 1 1/8 ounces of lead shot, and try to get a nominal velocity of 1200 FPS.

You know why we can't do that? It isn't the hull, it isn't the primer, it isn't the wad, it isn't the shot charge. It is the "BURN RATE" of the powder that prohibits us. Use 21.0 grains of IMR SR7625 and those exact components and we have a great load at the velocity we are looking for.

WHY? Because we are now using a powder with the correct, go ahead you can say it GG, Burn Rate!!

Like I said before GG we aren't arguing over the fact that powders do develop different pressure/time curves, Just the defintion of burn rate.

Besides the fact that when you edited your response you proved my point,

Thank you!

You have got to be the most pig headed, stubborn jerk I have ever dealt with. Give it up!!

I've heard it put as burn rate class or burning rate class. It is an industry "buzz word" or professional jargon for the intrinsic burning characteristics designed into the propellant. The actual burn rate of a batch of propellant is determined by a standard closed bomb test. This bit of confusion might be the fly in the ointment here. The combustion rate we actually realize in our reload will very likely not be the same. The conditions are different.

I certainly hope this herlps to nail it down. Otherwise, all hell is liable to break loose again. Laughing

PS, thanks for being such a gentleman DC. Rolling Eyes

Now I have question. What happens if we change just one of the factors in the recipe you used other than the powder charge or the shell? Can we possibly obtain a different result if we do? Suppose we wish to get a velocity of 1150 FPS? Could we possibly use a cooler burning primer to get that result?. How about different wad? How about adjusting the crimp so it is deeper and more resistant?

It is my understanding that if we manipulate the recipe, we will change the results to some degree. Doing so can and will change how fast the powder charge is consumed and will change the pressure curve as well. These changes in velocity and pressure are not always determined solely by the amount of powder in the charge or by the volume of the given combustion chamber. Something else must be changing as well. Could it be how fast or slow the powder is burning under the changed conditions?

DC, do please try to understand that we are all free to agree or disagree according to our individual knowledge and understanding. Doing so helps us all reach an understanding. This does not mean we are stubborn, pigheaded, or jerks or even that we are trying to piss you off. I don't understand why you insist on taking everything so personally as if you own or control this site. Your barrages of temper are getting to be a bit too much. I can't control you. It is not my place to. But you can. Will you at least think it over? Thanks.