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Ike asked in SportsOutdoor RecreationHunting · 2 years ago

Why not design firearm bullets to be longer instead of wider?

I don't have a real indepth understanding of bullet design that I'm hoping others can clarify for me.

From what I understand, a heavier bullet has the advantage of maintaining energy long while in flight. Smaller diameter bullets, however, have the advantage of a better ballistic coefficient.

Using military rounds as an example, what are the advantages of a .308 over that of a .223 other than weight? Why not design a .22 caliber slug with more length, giving it more weight, but a better BC and sectional density?


Just to clarify: I understand that a wider bullet makes a bigger hole, but from what I understand, this is an overrated argument some people use to explain why the .45 ACP is better than the 9mm Luger. Is my previous statement made incorrectly?

12 Answers

  • Quinn
    Lv 6
    2 years ago
    Favorite Answer

    You are over looking another important factor in ballistics which is bullet construction. Just because the bullet has a higher velocity does not necessarily translate to effective energy transfer. By that I mean during penetration and travel through tissue, how much energy is actually transferred to the wound cavity. If a bullet is too fast and it's small caliber gives it a high BC, then there is a higher chance of over penetration or shoot-thru which means it travels out of the wound cavity and that can only happen if not all of its energy has been absorbed. If the bullet is still travelling then it must still retain some energy else it wound had stopped.

    A larger frontal area acts like a more effective speed brake in tissues bleeding off energy into the wound cavity.

    As for why not a long bullet, there are 2 major factors to consider:

    1) The longer the bullet the harder it is to stabilizing it in flight. A longer bullet would require a higher spin rate and that means a shorter twist and you may run into a limit whereby the casing would be ripped off in the barrel because you have to spin the bullet at a much higher twist rate.

    2) Problem with bullet fragmenting on impact. A long bullet tend to keyhold upon impact and breakup in smaller pieces. For hunting, this could ruin your meat or the smaller fragments (which will have a lower mass) may not reach deep enough to hit the vitals for a clean kill.

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  • 2 years ago

    We have, look at the overall history of bullet designs and they've gotten smaller and longer, but only to a certain degree otherwise it would not be practical. Ballistics coefficient, terminal ballistics, weight, recoil, size, case capacity, magazine capacity, etc.

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  • 2 years ago

    the shape is all science.

    coned for flight, fat in the back for added stability.

    assuming your taking about rifle rounds. handgun rounds are different because of size constraints

    since your asking i assume you arent a reloader, because if you were, youd have a better understanding of why bullets are the weight and size they are

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  • 2 years ago

    Modern bullets ARE longer than they are wide. It does not matter the caliber, they are all longer than they are wide. They all pretty much have a Spitzer tip which cuts thru the air better. As far as weight, light weight bullets are slowed by the air faster. If you try to make a small caliber bullet as heavy as a big caliber bullet it will be too long to work well in the gun. The first change you would have to make is the rate of twist on the rifling since longer rounds engage them differently than shorter rounds. The main advantage of the 308 is it has better effect at greater distances.

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  • 2 years ago

    There is a lot to terminal ballistics besides bullet weight. Sectional density, velocity, expansion, weight retention, fragmentation, etc.

    Things like ballistic coefficient only account for drag. What about wind drift (far more difficult to calculate a firing solution at distance).

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  • 2 years ago

    Some are designed that way. It all depends on your ballistic needs. Range, what you need to knock down.

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  • 2 years ago

    "Smaller diameter bullets, have the advantage of a better ballistic coefficient. " This is an incorrect statement.

    A coefficient is a ratio. The ballistic coefficient could be stated as the ratio of the mass of a bullet over its cross sectional area times it's aerodynamic drag coefficient. Since it is a ratio, it is possible to design any two diameter bullets to have the same BC.

    What you are describing has been done, VLD bullets are bullets that have the lowest possible drag for a given caliber, they require faster twist rate rifling, which gives a practical limit to the length of the bullet that can remain stable in flight.

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  • 2 years ago

    When it comes to bullet/cartridge design, for every change, there is a trade off.

    Lets just say you take a standard .223 and redesign it with a longer heavier bullet but keep the size and maximum pressure the same - you would lose muzzle velocity resulting in less range and more compensation required when shooting relatively long distances.

    You could achieve equal velocity by increasing the overall size to allow more space for powder, and increasing the maximum chamber pressure. But those changes come with trade-offs as well. Larger cartridges mean either bigger magazines or fewer rounds per magazine. The cartridges are heavier so a soldier in combat can't carry as many rounds. The cartridges would cost more to produce since they use more lead, more powder and more brass. The guns would be heavier since the barrels would need more steel to withstand the increased pressure, and would probably need longer barrels to get that velocity.

    So you'd have a cartridge with a longer heavier bullet of the same diameter and velocity. But the guns & ammo would be more expensive and heavier.

    There are good reasons why the US armed forces downgraded from .308 to .223 for standard issue battle rifles.

    Additionally, if you were to go design something like that, you have to actually break into the market. There are hundreds of calibers with standardized design specs, but only a few dozen have ever caught on enough to be considered common. Most buyers will stick with what's already common and readily available on the market. The only realistic way for a new cartridge to gain popularity is to win a government contract for military or law enforcement use. Otherwise you'll just end up adding one cartridge nobody's ever heard of to those giant posters.

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  • 2 years ago

    In developing a light arm weapon system (and it is a "system", because the rifle and the cartridge have to work together), everything is a compromise. There trade offs between size, weight, ballistics, terminal ballistics, recoil, firearm design, and effectiveness at any particular distance or in any particular role. That said, there is a constant search for that next better cartridge.

    Longer bullets in the same rifle action either mean you have to seat the bullet deeper in the case, which means a bigger diameter case to hold the powder; or it means a longer cartridge, which would mean a longer magazine. Either way you have increased overall weight and volume.

    In the example you mentioned, the .308 Winchester cartridge is larger, heavier, requires a more robust rifle, and has higher recoil. In a battlespace where most engagements are 300 m or less and volume of fire is part of the tactical doctrine, a soldier can carry more that twice as much .223 ammo and keep it on target with a lighter rifle.

    For the .223 military cartridge (5.56x45mm), 62 grains is the standard issue NATO bullet, but longer 77 gr bullets are commonly used to achieve longer ranges out to around 800 meters. Any longer and there are problems with fitting in a standard magazine.

    The past several years have brought different cartridges to the AR-15 platform, including:

    6.8 SPC

    6.5 Grendel

    .300 AAC Blackout

    and more...

    The .224 Valkyrie has been introduced recently that uses heavier 60-90 gr .22 cal bullets. The 90 gr bullets are supposedly capable of 1000-1200 meters. With the longer bullet, to keep the full cartridge length short enough to fit a standard AR-15 magwell, the .30 Remington case was necked down to .22 caliber, which means you can't use a standard magazine and can't hold as many in the same size mag.

    As for the .308 Winchester, the narrower and lighter 6.5 Creedmoor (that can share the same magazines) provides a flatter shooting cartridge that is capable beyond 1000 meters.

    Finally, the Military is looking to replace the .223 cartridge altogether and is looking to develop a new standard caliber in the 6.5-6.8 mm range.

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  • 2 years ago

    A very slender (but long) slug will pierce the enemy, but not do any real damage. Like getting poked with a needle. It could go right through you, but you would be fine.

    A good compromise is long slender bullet that opens up upon impact , so it might hit like a needle, and then open up to the size of a quarter and do a lot of damage before it exits

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