Black Powder Ballistics

[knight0334]

Normally I would think the .36 would penetrate deeper because it has less surface area... but the Taylor KO formula seems to take that into account and indicates that the .44 has enough mass to overcome that and still yield a better result.

Frontal area and shape does play an important factor in penetration. A needle is more likely to penetrate further than a steel BB would if they have the same weight and velocity.

Its one reason why most most bullet proof vests will stop a somewhat rounded nose handgun bullet - but will not stop a rifle bullet, or even a sturdy knife.

The difference between a .36cal ball and .44cal ball in shape and frontal area is minimal. So energy and momentum would would be the prime factors.

[f14tcat691]

Well I'm back. And the 450240 is a conversion factor. Since you start out in fps^2 x grains and end up in ft lbs. 1lb/7000 grains gets you to pounds but the funky part is fps^2 (applied as fps x fps). So to get to ft in ft lbs, you use 1/64.32 fp(s^2) (written as f/s/s). Getting rid of all the seconds and one foot on the top and the only one on the bottom.

The picture sort of explains it all.

[tsafa]

Well I'm back. And the 450240 is a conversion factor. Since you start out in fps^2 x grains and end up in ft lbs. 1lb/7000 grains gets you to pounds but the funky part is fps^2 (applied as fps x fps). So to get to ft in ft lbs, you use 1/64.32 fp(s^2) (written as f/s/s). Getting rid of all the seconds and one foot on the top and the only one on the bottom.

The picture sort of explains it all.

That is pretty cool how you explained that. Thanks for taking the time to think this through and posting.

I have some new tests results I will be posting later today shooting a 485 grain bullet out of a blackpowder rifle.

[tsafa]

I did some more testing with heavy bullets in my 50 cal Thompson Flintlock Rifle. The results are pretty astounding to me.

Barrel..........Powder by Volume..........Bullet Weight.........Average Velocity.........Energy.............Momentum
28 inch...........80 grains 2F........315 grain, .490 conical.........1186 ft/s..........984 ft-lbs.............53.37 ft-s
28 inch...........80 grains 2F........485 grain, .490 conical.........986 ft/s...........1047 ft-lbs............68.31 ft-s
28 inch..........100 grains 2F........315 grain, .490 conical........1307 ft/s..........1195 ft-lbs............58.81 ft-s
28 inch..........100 grains 2F........485 grain, .490 conical.........1089 ft/s..........1277 ft-lbs...........75.45 ft-s
28 inch..........120 grains 2F........315 grain, .490 conical.........1345 ft/s..........1265 ft-lbs...........60.52 ft-s
28 inch..........120 grains 2F........485 grain, .490 conical.........1234 ft/s..........1640 ft-lbs...........85.49 ft-s
28 inch..........140 grains 2F........315 grain, .490 conical.........1471 ft/s..........1514 ft-lbs...........66.19 ft-s
28 inch..........140 grains 2F........485 grain, .490 conical.........1345 ft/s..........1948 ft-lbs...........93.18 ft-s

After studying the results of the 315 grain and the 485 grain bullets in the 50 caliber Flintlock there is one thing that needs to be said... SIZE DOES MATTER

The powder was a mix of 50% 2F GOEX BP and 50% Pyrodex RS. The reason for this mix is because I did not have enough GOEX available. Previous testing has shown only a very slight increase in Pyrodex results. I wanted the to include as much real BP as I could because BP ignitions are more reliable with Flintlocks. I did not have a single misfire.

It is also interesting to note that I was shooting the lead bullets of 315 and 485 grains into a tree-stump that was about 8 inches in thickness. No exit, but the 50lb stump was jolted pretty good. The soft lead seems to do a good job of expanding inside the stump and transferring the energy to the stump. Lead used in Muzzle-loaders is 99% pure lead and much softer then the lead used in modern firearms.

I have also updated my webpage to include Momentum calculations for all my previous tests:
http://poconoshooting.com/blackpowderballistics.html

[tsafa]

I have some new test results on a Flintlock Pistol.


50 Cal Traditions Pirate Flintlock Pistol 10 inch Barrel Stainless Steel

Load.............................................. ......bullet..................Velocity............ .Energy.............Momentum

50 grain 2F GEOX Black Powder.........173 grain, .490 ball.........464 ft/s...........83 ft-lbs............11.46 ft-s

50 grain 2F GEOX Black Powder.............316 grain conical.........497 ft/s..........173 ft-lbs...........22.43 ft-s

70 grain 2F GEOX Black Powder.............316 grain conical.........965 ft/s..........653 ft-lbs...........43.56 ft-s

Repeated tests with the Pirate Pistol favored the conical over the round ball with a greater velocity. You would expect the lighter ball to have a greater velocity but this was not the case. The conical provided more surface area which was harder to seat and consequently allowed more pressure to build up behind it, resulting in higher pressure and velocity. The pistol has a rifled barrel. No patch was necessary or possible due to the tight fit. The fowling in the barrel provided maximum tightness.

[Biggfoot44]

Normally I would think the .36 would penetrate deeper because it has less surface area... but the Taylor KO formula seems to take that into account and indicates that the .44 has enough mass to overcome that and still yield a better result.

OK, OK Just chastise me now ! This is necro thread of all time ! But in my defense , the Original Poster's publishing this same data on his Website, still remains one of the most searched such information on the internet.

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In comparing the ballistic properties of various projectiles of various diameters, there is one more important measurement/ factor, in addition to energy and momentum. Sectional Density , aka SD .

Vastly oversimplified, it is a factor of weight and cross Sectional area ..Vaguely like measuring pounds per sq inch for footprint of off road vehicle , or floor loading for a watered or gun safe .



So I whipped out the calculator function on the flip phone , and ran some numbers comparing. 36 RB and .44 RB .( using pre loading diameters )

.36 RB. SD - .0822
.44 RB. SD - .0977

So what's that mean ?

Even if you had a hot .36 Round Ball loading that matched the Momentum of a light .44 Round Ball loading and neither expanded , due to inherent physics, the .44 Round Ball would have +/- 15 % more penetration.