Why do rifles use smaller bores than pistols? Im not a troll

Because they fire smaller longer bullets that are faster with greater energy than a shorter fatter round

Look up muzzle velocity

thiccer bullet = more air friction = less velocity
the more the mass of the bullet is the more energy is needed to send it fast
smaller baby bullet = faster = less surface area on bullet as well = better penetration because fast and skinny like asian penis

bigger bullet can cause more damage but smaller bullet can fragment
if we take AK bullet of 7.62x39 it give good punch but it not split into multiple parts cutting everything inside

if we take call of duty m4 bullet of 5.56x45 it go very vroom fast and split into many part and cut inside many but have less punching

>>34839425
because the pistol bullet is pretty small still, just wide because thats the easiest way to fit the most mass into a compact package while rifle bullets are long and cylindrical which is balistically superior. a 9mm pistol bullet is about twice as heavy as a 5.56 rifle bullet too, but the latter goes three times as fast therefore it carries more energy.

File: muzzle-energy.png (129KB, 868x734px) Image search: [Google]

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It is a combination of reasons.
Physics
Ballistics
Pressure
Weight.

The most aero dynamic shape for a bullet is long and skinny.

If you go up in caliber your bullet gets longer to maintain the same ballistic coefficient.

As you increase the size of the bullet, you must increase the powder load required to get it moving.

This increases the recoil of the round. Newtons 3rs law

Rifle rounds move fast. Pt1.
Why? Gravity. If your trying to hit a target 200-500 meters away, every second your round is in the air it is dropping by 9.8m/s^2. Well if you have a slow round , like a pistol round , your going to have to make some crazy elevation adjustments.

Rifle rounds move fast pt2.
Kinetic energy is king.
The formula for which is 1/2(mv^2).
You can see that the velocity of the round is squared. Speed is a bigger factor in ke then mass. (See image for comparison of ke )

There is pressure.
So, you have a round and need to move is fast, how?. What moves a bukket is the difference in pressure behind the bullet vs infront of it.
The pressure behind is created by the expansing gasses caused by the combustion of gun powder.

That pressure is contined momentarily, by the cartridge,( supported by the chamber) the bullets fit in the neck, and the friction between the bullet, and the barrel at the chamber throat.

For an instant the bullet can hold back the gases, but then the force of the gas overcomes the force of static friction and the bullet accelerates forward.


Why forward? That is the path of least resistance. Because the chamber and bolt are designed to contain the massive amounr of presure the round generates. For the 223 roun that can be 55,000 psi.

To accelerate a larger diamatwr, longer, and heavier round, that chamber pressure is going to go even highet. Needing a bigger , stronger design to contain it.

Lastly weight.

As a soldier you need to carry your gun and ammo. The trade off is more light ammo or less heavy.

>>34839425
Muzzle velocity and a flat trajectory is more important than having a pistol round. If you wanted to use a rifle with a 9mm bore but similar proportions to a rifle round it would be very heavy, and recoil a lot. With that being said SMGs are far less prevalent.

>>34839425
Because pistols have short barrels
>low potential for velocity
To make up this they fire heavy projectiles

>>34839425
F = MA

>>34839446
Ivan is that you?

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>>34839628
Noticed yours was missing something

>>34839425

a 5.56x45mm leaves the bore at 3000 fps and produces around 1100 ft/lbs

>>34839425
Energy = (1/2 Mass) Velocity^2

As you can see, mass is less important. However, heavier bullets buck the wind better. You have to find balance.

>>34842415
Heavier means more momentum which means less efdected by environmental conditions like wind as well as better retention of velocity and energy at longer ranges.

Unrelated but equally dumb question from a noserve, explain this to me

>Light Infantry are guys who walk
>10th Mountain are guys who hike
>Mechanized infantry are guys who jump out of vehicles
>Airborne jump out of planes
>Air Assault jump out of helicopters
>Marines (use to) jump out of boats
>MEU get killed by their ride

Is that right?

>>34839425
rifle bullets aren't smaller. they are longer with a shorter diameter