Home Forums Hunting & Shooting Handguns PERFORMANCE CALCULATIONS IE MUZZLE ENERGY

For those shooters who may not yet know and in memory of the great shooter who gave me this formula 35 years ago here is how to calculate muzzle energy:
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<br>ME=(V2/7000)/64.32 x bullet weight in grains.
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<br>IE My old .44 Mag service load (in the days when carrying handloads wasn't antisocial for law officers) sent a 250 grain Keith bullet out of the 4" barrel Model 629 right a 1000 fps with a resulting ME of 555 ft lbs.
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<br>1000 x 1000 = 1,000,000 / 7000 = 142.85714 / 64.32 = 2.2210 etc. x 250 = 555.
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<br>FYI, Good shooting!!
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<br>Deputy Norm

Thanks Deputy_Norm, I been counting on published data before seing this. Now I can figger it out myself, cool.

What does the 555 Ft lbs mean? That bullet certainly cannot push or otherwise move 555 pounds
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<br>I contend it is better to know the actual work or effort capable of the projectile your launching to make a fair judgement of it's potential. The ME formula of old is only advertising hype and has zero bearing on the reality of the "power" in your hands.
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<br>If you really want to see what the projectile is capable of multiply the bullet weight in grains times the velocity in FPS and Divide by 7000( grains in a pound) this will tell you what the projectile can actually do in "pounds feet". Not the Bogus Muzzle energy formulas given by the firearm industry to make the high velocity magnums seem much more powerful then they are.
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<br>The above example using the 44 magnum, 1000X250=250,000/ 7000=35.7 pounds feet. Yeah a 250 grain bullet at 1000 fps will probably move 35.7 pounds but no chance will it even budge 555 lbs! My 458 Lott with 500 grain bullets won't budge 555 pounds of anything!

That light bulb just went on as I read your post. Here is a direct experence with the formula you contend is better. I have made up a bullet stop that I put on top of a stack of concret blocks. I set it up at 25 yards out side of my shop. I have a bench set up inside that I shoot from on those real nasty days when I don't want to be outside. This stop is a wooden frame with a 18X24 piece of 5/8 steel plate. Weighs in at 46lbs. I used to shoot .41caliber handgun loads 210g/19.5/2400 for about 1200-1250fps. Never had any problems with the stop. The very first time I hit the stop with my new loads that use 250g bullets at around 1400-1450fps the stop was knocked of the blocks. Just ran your formula 36V51+. No wonder it fell. The light came on.

JJHack:
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<br>I see your point and have thought about that many times. Especially when I saw a person wearing body armor get shot at close range with a .308 Winchester.
<br>He only weight 180 pounds and the 2700 ft lbs didn't even knock him down.
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<br>I just consider the me calculation to be a relative number when compared to other rounds. For example it is easy for me to see that the 555 vaughted foot pounds probably had better stopping power than the .25 ACP that I had in my jacket pocket at 50 foot pounds.
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<br>Also actual field experience has shown me that the .357 Magnum 145 Grain Silvertip at 500+ foot pounds did a better job than the .38 Special at slightly more than 200 foot pounds.
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<br>A lot of shooters use the foot pound number as I do a guide for relative power of a round. It's roughly accurate in my experience.
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<br>Of course 555 foot pounds whizzing by a targets ear isn't going to be as effective as the 50 foot pounds going into the same ear.
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<br>Good shooting.
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<br>Norm