Anonymous
Anonymous asked in SportsOutdoor RecreationHunting · 1 month ago

How can a .223 Remington have a higher velocity than a .308 Winchester?

Okay I read that a .223 remington can travel faster than a .308 winchester.

A .308 has a LENGTH of 51 MM and a WIDTH of 7.62 MM

A .223 Remington has a LENGTH of a 45 MM and a WIDTH of 5.56 MM

So if a .308 Winchester is BIGGER in BOTH WIDTH AND LENGTH, it must have MORE gun powder than a .223 remington.

And MORE gun powder means MORE velocity.

If they BOTH came out of say a 20 inch barrel, how could the .223 Remington be FASTER when it has LESS gun powder?

Other than barrel length and amount of gun powder behind a bullet, what else does the velocity of a bullet depend on?

15 Answers

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  • 3 weeks ago

    For any given amount of powder you have to deal with mass (the weight of the bullet), speed of the bullet and chamber pressure. So lets say you got a heavy and a light bullet. The light bullet is going to go faster than the heavy bullet. With the 308 you are dealing with bullets around 160 grains. With the 223 you are dealing with bullets around 55 grains. So the little 223 goes much faster because it is a third of the weight.

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  • 4 weeks ago

    Mass of bullet is large factor . 10 or 11 gram bullet pushed by 50,000 pound pressure will be slower than 3 or 4 gram bullet pushed by same pressure from barrel. Note that figure given are about industry standard- .308 from 145 grains to 170 grains as NATO standard bullets, Army and the 5.56 Viet Nam M16 used a 52, 55 grain bullet while current SS109 (?)is 62 grain  bullet

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  • Mr.357
    Lv 7
    4 weeks ago

    That Newton guy made some law about equal and opposite reactions.  Energy is the velocity squared multiplied by the mass.  A .223 bullet is MUCH lighter than a typical .308 bullet.  They do or did make a sabot bullet for the .30-06 which is a larger case than the .308 case.  The bullet was about 55 grains and was MUCH faster than a similar bullet out of a .223.

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  • 1 month ago

    Think of the 308 as a big rig and the 223 as a motorcycle. A big rig is running about 550 horsepower and your standard 1000cc sport bike is closer to 170hp, while being a fraction of the weight.

    Power to weight is the name of the game.

    But the extra weight of the 308 allows it to travel further, hit harder and be less effected by wind as well

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  • 1 month ago

    You are confusing cartridges, the names of the cartridges, and the bullets they use.  The .223 Remington and .308 Winchester are "cartridges" and as such do not have any velocity to speak of.  Only their bullets actually have measured velocity when they are shot from a gun.   So YES, a .223 Rem BULLET has a higher velocity than a .308 Winchester BULLET when fired from barrels of comparable length.

    The name of a cartridge only gives nominal measurements.  So just to be clear the .308 Winchester CASE is about 51 mm (51.2 actually) and the .308 Winchester BULLET is actually .308" or 7.8mm and is intended to be shot from a barrel with a BORE of 7.62mm (.30").  The .223 Remington CASE length is 45mm and BULLET is .224" or 5.7mm in diameter and is made to be shot from a barrel with a BORE of 5.56mm (.219").

    There is not enough information from the cartridge name to know the diameter and volume of the case or the length and weight of the bullet or the length of the entire cartridge.

    You are correct that the volume of the .308 win case is larger and it holds more powder.  HOWEVER, that is insufficient information to tell you if one bullet is faster than the other.   First, they may use different powers that burn at different rates and generate pressures at different rate.  Second the VOLUME of the 7.62mm bore is larger than the 5.56mm bore and it would take more powder to generate more gasses to achieve the same pressures, and pressure translates into velocity.  Finally, you have to consider the weight of the bullet as the heavier bullet under the same conditions will be the slower bullet.  .223 bullets tend to run in the 55 to 77 gr weights, whereas ..308 bullets generally run 150 to 180 gr.

    Remember Kinetic Energy = 1/2mv^2.  For the same kinetic energy a heavier bullet has a lower velocity.  A firearm is a machine that converts the potential energy stored in the powder by rapid oxidation when burned, which results in a release of gasses that  increases pressures, which pushes the bullet out of the cartridge and down the barrel.

    So in short, a .223 rem bullet is faster out of the same length barrel as a .308 win bullet because the volume of the bore is less (higher pressure with less powder) and the weight of the .223 rem bullet is roughly 1/3 to 1/2 that of the .308 bullet. 

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  • 1 month ago

    I guess you have never had a motorcycle pass you on the highway?  They are much smaller than you - and are faster?

    Tanks are bigger and faster than motorcycles... tanks can do 65mph but a smaller motorcycle can do 170mph.  How do you rectify that fact.

    If I roll up a spit ball and shoot you with it, its a tiny piece of paper and spit moving 20 feet per second.  I throw a 1/2lb rock at you 20fps you are going to scream and bleed.  Hit in the right place, you might get hurt bad.

    In bullets we care about speed and mass first, then bullet design for aerodynamics. I hit you with a round 1lb ball in the chest you will scream.  I hit you with a 1/64lb knitting needle pointy end first you will die.

    223 is fast and small.  308 is slower than 223 however the bullet physically heavier and visibly larger.  If you multiply weight x speed of each you get ft.lbs (1lb = 7,000 grains)  You will notice the 308 is considerably more powerful by many times.

    Strap-it:  This message and the math contained is only for use by the person who asked the question.  YA is not a message forum.  If you want to leave nasty comments - please go find a message forum.  I about never come back to re-read what others have written unless I am curious.  Thanks to you - I am no longer curious.       

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  • Robin
    Lv 7
    1 month ago

    you are so wrong. The 308 (7.62) bullet has a diameter of 7.82 and mine have a length of 1.25 inches

    plus the case is not filled to capacity. The 223 is a third of the weight of 308

    compair a speedboat with a super tanker

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  • Anonymous
    1 month ago

    I think you'd better stay in school, as your logic is lacking.

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  • BBean
    Lv 7
    1 month ago

    Your question reminds me of a cattle rancher that showed me and banker friend the same herd of cows 3 times by narrating the 3 different routes to the same pasture attempting to increase net worth for a loan.

    The path you are attempting to lead YA section down with given measurements are for all practical means insoluble. 

    Try grain weights, twist ratios, powder burn rates, and bullet to case capacity ratio. Maybe a booster course in laws of inertia also.

    • ...Show all comments
    • Staap It
      Lv 7
      1 month agoReport

      Or as Higgy says ... "Just castrate the somabitch and come back and ask us what to do later".

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  • Anonymous
    1 month ago

    Because .223's are smaller, take up less mass when flying, and therefore it's easier to make something smaller go faster than something bigger. 

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