Calculating Muzzle Energy

(Vel X Vel X Bul Wt in Grns) Hey Ganderite, I figured this formula years ago which works 100%................
..............450222


It took some time to calculate the constant 450222 but it is more than 1/10 of 1% accurate...............I always remembered the constant because those were the largest and smallest cartridges I had at the time........450 Ackley and 222 Rem
 
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Yep, used that formula for a long time.
Only my figure was 450240, I didn't have the guns to remember anything by!
And here's a trick.
If you are using a little pocket calculator, and take vel. squared times bullet weight, you have run out of space on the calculator.
So, vel squared divided by 450240, times bullet weight and everything works.
 
450282 = 7000 (#grains in a pound) X 32.163 (acceleration due to gravity) X 2

This is from the formula E=1/2mv^2

450222 is close enough

Dan
 
I ran literally 100s of different energy listings from different load books and got several different constants and then averaged these constants to come up with 450222, they were all in the 4502xx range and averaged like I said 450222. I'm sure there were variations in velocities, and rounding happening with the energies so that's why I had a dozen different constants initially which was why I did the average...........Need came from wildcatting and not having velocities high enough to just look up the energy. There were no 500 gn bullets at 2550 fps in the books in them days, which my Ackley was doing, and a couple other odd balls........

I also calculated a constant for using to get internal case capacity from the outside dimensions of a case. Don't have it in front of me but I have it written down in a book. I took a book which listed the internal capacity of over 100 common cartridges and then calculated the external dimension of every one of the cartridges listed, using the drawings in my loading manuals, and came up with a constant that would give me the approx. internal capacity of any wildcat that I could imagine. Although not absolutely precise, I found it to be very, very close and certainly close enough for my needs. In doing the belted mags I just ignored the belt and my number still worked within a 1-2% accuracy which I have found more variance in different makes of brass than my formula gives.

I have always been a bit of a math geek, so doing these calculations interested me greatly at the time, as applied to wildcats. The internal case capacity constant took me about 5 hours as I recall, and of course the larger the sampling one does the more accurate one can get. I also did a complete back calculation on the 100 and some odd listed cartridges to get my extreme margin of error and confirm my constant. I was surprised how accurate it was to known internal capacities and my extreme MOE was less than 3% and only on 2 cartridges. The reminder all fell within 1-1.5%...............
 
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C-FBMI

Every time I see your post I wonder if it is a 180 or a Super Cub. On floats, of course...

Actually Ganderite it WAS a Cessna T337B Skymaster...........inline twin engine I rolled into a ball about 5 years ago. No floats but retract, now I have a PA 32-300 Cherokee Six single engine........no floats either. I actually have never got my float rating, all my flying was strip to strip for business, on wheels. Although I have done some float flying I have never been licensed for it............my kid is, but I never got around to it. I'm multi engine, commercial, night rated, but no floats.

New bird letters are C-GDXI which is affectionately known as Dixie..............
 
Actually Ganderite it WAS a Cessna T337B Skymaster...........inline twin engine I rolled into a ball about 5 years ago. No floats but retract, now I have a PA 32-300 Cherokee Six single engine........no floats either. I actually have never got my float rating, all my flying was strip to strip for business, on wheels. Although I have done some float flying I have never been licensed for it............my kid is, but I never got around to it. I'm multi engine, commercial, night rated, but no floats.

New bird letters are C-GDXI which is affectionately known as Dixie..............

Wasn't there a thread started on what to name a female pewch?

Dixie would be an endearing handle..............?
 
The "mixmaster" was fun, just not well suited to this country of 1000 ft strips, she wanted 1500 and more. In the air she was an amazing machine, 185 kts cruise at 12,500 and the only aircraft I have ever flown that would do a 180 deg bank turn for a full 180 degs without the nose falling in. A riot to fly but just too much of a ground hog for this country. As a pavement to pavement down south commuter she would have been unbeatable, and as a bird dog for the water bombers she was excellent, which my bird was for more than 2000 hrs., owned and maintained by Airspray.
I only had about 400 hrs on her when I rolled her up, my first was a Cessna 210-5 or 205 which I put well over 1000 hrs on before I iced her up and lost her in the trees, then came a 206, which I only had for a couple hundred hours and I hated that plane, actually sold that one still flyable. Now I have Dixie and she is a wonderful short strip performer and fairly quick in the air at 140 kts @ 12.5 gpm, I've only got about 20 hrs on her yet as the kid does most of the flying now, but I can still put her down in places he hasn't got a hope yet...........However I guess that's my 3000 hours and 35 years experience against his 300 hrs and 10 years.

Sorry for the aircraft hijack OP........Oh wait, you are the OP...........
 
(Vel X Vel X Bul Wt in Grns) Hey Ganderite, I figured this formula years ago which works 100%................
..............450222


It took some time to calculate the constant 450222 but it is more than 1/10 of 1% accurate...............I always remembered the constant because those were the largest and smallest cartridges I had at the time........450 Ackley and 222 Rem

Derived from the equation,

Kinetic Energy = 1/2 Mass x velocity x velocity , where mass= grains divided by 7000, velocity in ft/sec
 
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