# How many foot pounds of energy can 55.6\223 shoot?

Discussion in 'AR-15 Discussion' started by Abc1911, Sep 5, 2012.

1. ### Abc1911New Member

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How far will the bullet lose its energy? Can you kill a deer at 500 yards?

2. ### mountainman13New Member

Depends on the round weight and grain load.

3. ### SSGN_DocWell-Known Member

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It's not all about foot pounds of energy. Bullet placement. Bullet weight. Bullet construction. Are all factors to consider.

Then consider the size of deer in your area.

There are ballistics tables on the web that tell you what the performance of a given bullet should be as far as speed, energy, and drop based on the bullets speed at the muzzle. The tables wont show how the bullet will perform once it hits a 110 lb swamp deer at 75 yds vs. what it will do hitting a western mule deer that weighs nearly 200 lbs on the other side of a clearcut at 250 yds.

Too many variables in the field and too vague a question to give a definitive answer to.

But to answer as worded I will say that it loses some energy as soon as it leaves the muzzle and continues to do so until it comes to rest. Yes you COULD kill a deer with it at 500 yds.

May not be the most efficient choice though.

4. ### kryptar19New Member

27.5gr of B-Lc(2) powder

^^This is my personal load that can kill them pretty well out to 300 with.
Ill get you a web sight that you can run load data thru later.

But like SSGN_Doc said, consider the size of your deer. I live in Arkansas and the deer here do not get over 220lbs often. They usually fall between 100-170.

5. ### CoyotenatorMember

Can't use .223 in Washington for deer.

Formula for ft.lbs. is velocity in fps squared X bullet wt in grns / 450,240
3200X3200=10,240,00 X 55grns=563,200,000/450,240=1251 ft.lbs at muzzle

6. ### mountainman13New Member

Very good.
Know how to calculate tko factor?

7. ### canebrakeNew Member

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It's 5.56...................

55.6 is 2 13⁄64in

8. ### mountainman13New Member

Now that would be fun! Lol
Nice catch cane. I didn't even notice.

9. ### CoyotenatorMember

Bullet wt in grns X bullet diameter in inches X velocity in fps/7000

10. ### mountainman13New Member

I find it interesting to compare the two together and then compare to other calibers. Idk,I'm a dork. Lol

11. ### CoyotenatorMember

The more you know the more inteligently you can make decisions about caliber and loading, that's not being a dork ,that is preparation for the hunt.

12. ### mountainman13New Member

Yeah but fpe aren't everything and there isn't really any science behind tko factor. It's just kinda interesting and doesn't hurt to know.
I mean my glock has about double the tko factor of the AR based off those numbers. Lol

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Agree that deer in the SE run a lot smaller than their Western cousins.

Here in VA, the .223 is not legal for deer at any range. Assuming that you need 750-1000 ft lbs of energy for a CLEAN kill on a deer (a generally accepted number, depending on the author)

Using Remington's data on a 64 gr soft point- it starts with 1322 ft lbs at muzzle, at 100 it is 1022, at 200 yds it is 780, and at 500 yards, about 313 ft lbs.

Would also mention that the "kill zone" on a deer is about 5 inches across. Can you shoot minute of angle from the position you use when hunting? BTW, a 10 mph crosswind will move that bullet laterally about 38 inches at 500. If you were zeroed at 200, you are holding over Bambi by 53 inches. If Bambi is walking, the flight time is about 0.75 seconds- how much would you lead him to keep the bullet in that 5 inch circle?

CAN it kill a deer at 500 yards? Yep. And you CAN win the lottery tomorrow. About the same chances.