The chrono don't lie

[Hamourkiller]

The Brits learned long ago that for penetration on game you needed a hardened round ball. Less deformation means more penetration.

 

[longcruise]

That's a very good question.

Ah! I see you are new. There is a formula developed by the late Charles Davenport( the "Davenport" Formula ) that determines how much powder can be burned in a given caliber and length of barrel EFFICIENTLY.

AAAAaaarrrgh!

Ok, more questions still. This is the first time I've heard of a Charles Davenport in the shooting World.

Oh well, it was inevitable!! :haha:

 

[longcruise]

I went shooting today and found some strange data.

One more thing that could be worth mentioning is that sometimes the dang things do lie!!

Battery condition, sunlight, etc., can make a difference as the day wears on.

Also, you may already know this, but I'll mention anyway. When shooting black powder your screens need to be out there further than with the smokeless stuff. I can shoot with my screens at eight feet with smokeless but need about 15 feet with charcoal.

 

[paulvallandigham]

I am sure that the pass through are due to less ball deformation. Like you I have seen enough balls recovered under the farside hide, flattened like a quarter, to believe that this is so. Since lead flattens even at low velocities, high velocities will usually result in the ball remaining inside the hide.

Lead was an expensive commodity to the 18th and 19th century hunters. It was not a bad thing for them to recover the lead, as they melted it down again to make another ball. Powder was cheaper than lead, but still an expense, when money and trade goods were also hard to come by. A lot of the old hunters were pretty frugal on the amount of powder they used, knowing that a slow moving ball would expand and remain inside the hide, too.

With heavy balls on deer sized game, a friend of mine picks his shot so that he is either breaking a front leg going in, or coming out of the chest cavity. That way the ball flattens, and is recovered under the skin on the far side.

 

[Billnpatti]

Paul is a very intellegent man and knows whereof he speaks. With all courtesies to Paul, let me hop in and answer that for you. The 97 grains is a theoretical number based on the Davenport formula. You multiply the volume of the barrel in cubic inches by 11.5 to get the grains of powder the barrel theoretically should burn efficciently. It is not absolutley accurate but gives you a darned good ball park number. The reason it is not nuts on accurate is because of so many confounding variables such as which brand and granulation of powder you are using and to a lesser degree, what patch and lube you are using. Not an absolutely accurate number but a good place to start looking for the optimum load.

 

[Zonie]

I'd like to emphasize that the Charles Davenport formula does NOT say that using powder charges above his recommended amount will NOT increase velocity.

Using powder charges above the value will indeed increase the velocity of the ball/bullet however not as efficiently. In other words above this value the shooter isn't getting as much "bang for the buck".

Well, maybe I should have worded that differently. The amount of "bang" will increase but that is due to the powder burning outside the barrel after the ball/bullet is long gone.

The breech pressures will continue to rise as more powder is added and these pressures also continue to increase after the "recommended value" is reached.

 

[Ballard]

Thanks much for the explanation!

 

[Dphar]

I have to ask. How did you determine that this man's rifle would only burn 97 grs of powder efficiently?

There is a fromula that tells how much powder a giver size/length will burn.
Its a guide what it really does is gives the point or diminishing returns.
Its not important how much powder it will burn its how does it shoot.
Still I would likely not exceed 120 in a 62 unless it just would not shoot with 120 or less.
I shoot 140-150 in a 16 bore (.662 ball). My 30 (with the patent breech) rifle makes 1600-1650 with 140-150 grains of FFG Swiss.
I consider 1600 the minimum since it gives a nice flat trajectory (point blank range) to about 120-130 yards. Flat enough for deer to this distance with no hold over.
Dan

 

[Dphar]

There is a good chance that the tighter loads are squeezing out more lube at the muzzle and the patch is drier where it rides the lands.
But sometimes increased friction can increase velocity since it may increase the initial pressure.
For a test wipe the bore with a patch to lube it before loading and see if this increases the velocity.

Dan