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What is.....

Discussion in 'Small Arms and Edged Weapons' started by TacticalTank, May 20, 2011.

  1. CPL Punishment

    CPL Punishment Member

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    Well, I for one found that interesting and concise. However, the forum engine won't let me salute you formally. So I salute you informally...

    SAAALUTE!
     
  2. Victor Gomez

    Victor Gomez Ace

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    Just to join Mr. Price in confusion I have found you can find an 8 MM gun but you had better check the bore and see if it takes .3ll or .323 caliber bullets. Then you must also find out if it is older than most it may also have a "rimmed shell" instead of the regular. I have heard of all kinds of results from the confusion and none of them are healthy. Yet frequently these guns are just called 8 mm. Then there is the 6.5 mm that can be Manlicher, Carcano or Swede and those are all different cartridges. I have a Swede and love how it shoots. So there is no reason we should give up, it is fun to learn about the differences because they are great guns with their own good points.
     
  3. T. A. Gardner

    T. A. Gardner Genuine Chief

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  4. TiredOldSoldier

    TiredOldSoldier Ace

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    Let's try to make some more heads ache. Why make your life difficult with F=ma ? I much prefer E=1/2 mv^2 after all it's the energy that does the damage to the target and it's a lot easier to work with muzzle/terminal velocity and bullet weight than with acceleration and force.
    According to the formula for kinetic energy above the energy of a bullet (or any other moving object) is determined by it's mass (calling it weight is not 100% accurate but will do) and the square of it's velocity, that explains why a heavy slow bullet will have less energy than al light fast one.
    That energy is mostly determined by how much "powder" you are burning, so, as CPL pointed out, it's really cartridge not bullet size that matters the most, other factors like "internal balistics", barrel lenght, rifling, etc, will affect muzzle velocity by determining how much of the "power" of the propellant goes to your bullet and how much is "wasted", and bullet aerodynamics, weight, etc. will affect terminal velocity (the speed it still has when it hits the target), but basically it's the initial "kick" behind the bullet that counts.

    In theory the same propellant charge will give the same energy to a light as to a heavy bullet but there are practical limitations to how big a charge you can pack behind a small bullet, and a large bullet does have some advantages such as loosing energy slower and being less likely to go all the way through the target so wasting energy "behind" it.

    USMCPrice, thanks for finally explaining to me when a 7.62 is not 7.62mm, now if someone will explain why a 7.92 Mauser is called an 8mm .....
     
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  5. Gebirgsjaeger

    Gebirgsjaeger Ace

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    As far as i know the name 8mm Mauser is coming from the Gewehr 88 which had a 8mm x 57 I round with an 8.2mm diameter. But i´m sure that other ones can explain it better.
     
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  6. USMCPrice

    USMCPrice Idiot at Large

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    Ulrich is correct. So if we're going all in, we will really confuse TT, but here goes. First the principle, when the propellent burns it exerts pressure in all directions. To the rear of the barrel, or breech end, pressure is contained by the chamber, bolt and casing. The chamber is shaped like the body and neck of the cartridge, the bolt contacts the base of the cartridge and holds it in place, when the propellant ignites the casing actually expands against the walls of the chamber, sealing it. This is why brass is the preferred material for cartridge casings, it's strength and malleability. Steel is good for its strength but is less malleable and the case doesn't seal against the chamber as well. Then you have the barrel throat, this is an unrifled section of the barrel where the bullet portion of the cartridge rests prior to firing. When the cartridge is ignited the pressure pushes in 360 degrees, the bolt, chamber walls and casing contain the pressure at the breech end. The walls of the barrel contain the outward pressures and the bullet contains the the pressure down the axis of the bore towards the muzzle. This pressure pushes the bullet into the rifled portion of the barrel which is slightly reduced in diameter thereby sealing the bore and cutting the rifling into the bullet. The bullet being the weakest point is pushed down the barrel towards the muzzle end.
    So here's the answer to the 8mm question, as Ulrich correctly stated the 8 x 57 I designed for the Gewehr 1888 had a bullet diameter of 8.08 mm (0.318 in). The 8 x 57 IS designed for the K98 had a bullet diameter of 8.2 mm (0.323 in) in diameter, the British that used the IS round in the Besa machine gun gave it the 7.92mm designation based upon bore size. The bullet is slightly larger in diameter so it is "squeezed down" to engage the rifling. Remember were talking hundredths and thousandths of an inch. It can be crucial though because the US Sporting Arms and Ammunition Manufacturers' Institute (SAAMI) will only certify 8 x 57 cartridges at lower chamber pressures than the European equivilent, The Commission Internationale Permanente pour l'Epreuve des Armes à Feu Portatives or C.I.P. because if you fire the IS round in a weapon designed for the I round the increased diameter of the bullet can result in a burst barrel or chamber failure.

    Besa machine gun:
    Besa machine gun - Wikipedia, the free encyclopedia

    Now I've given myself a headache, guess I'll go take a nap, or better yet take the dogs and the truck and head for the woods.
     
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  7. Gebirgsjaeger

    Gebirgsjaeger Ace

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    Don´t forget the rifle if you´re going to the woods! Thanks for posting your information.
     
  8. yan taylor

    yan taylor Member

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    You have to tread Carefully TacticleTank, a few Nations give different calibres for the same weapon, the Italians call the [FONT=&quot]Böhler 47mm L/36 anti-tank gun the M.47/32 (L/32), I my self got confused over Ammo in the past like the Soviet 76.2mm Pistol and 76.2mm Rifle ammo.
    Regards Yan.
    [/FONT]
     
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  9. USMCPrice

    USMCPrice Idiot at Large

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    Man I'm confused too :confused:. I never realized the Soviets had pistol and rifle ammo that large. Kinda dwarfs our .50 cal-1/2 inch-12.7mm round doesn't it? Damn a 76.2mm round works out to be 3 inches in diameter! :D Just kidding dude, I assumed it was just a typo and you were meaning 7.62mm or .30 caliber.
     
  10. yan taylor

    yan taylor Member

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    It had Been a long day (give me a break please)

    7.62x25mm (Pistol)

    7.62x54mmR (Rifle)

    Yan.
     
  11. machine shop tom

    machine shop tom Member

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    I don't mean to dig up an old thread, but there is something I must address.

    USMCPrice listed some information that is not accurate.

    "You have various other calibers that can appear confusing but aren't .30-06 is .30 caliber or .30 inch bore diameter, standardized in 1906 (7.62 x 63mm). NATO 7.62 X 51mm is .308 caliber, meaning the bore is .308 inches across. So basically they are both .30 caliber rounds, but the .30-06 is a slightly more powerful round even though it has slightly lesser diameter, this is because the capacity of the casing which is 12 mm longer. The difference in the two rounds is less pronounced than it would appear because when the 7.62 NATO was introduced, the lesser capacity case was partially made up for by a more powerful powder/propellant. Same with the British .303 basically a .30 caliber bullet, the actual metric equivelents are .30=7.62 .303=7.69 .308=7.82. Then you can throw in the main WWII German round the 7.92mm x 57 IS Mauser round (also called 8mm Mauser) is .311 inches in diameter, or once again basically a .30 caliber round. Then you have pistol bullets, 9mm is basically .35 caliber, so a larger diameter projectile than the .30 caliber rifle bullet but with much less power and range, because of a smaller casing with less powder capacity. The M1 Carbine, .30 caliber round was basically just an upscaled pistol cartridge. While the round was/is called the .30 carbine (7.62 X 33) it is actually 7.82 mm in diameter or .308 inches. Then you have the intermediate cartridges 7.62 X 39 soviet and the Germans 7.92 X 33 Kurz round (the round used in the StG 44), these rounds are less powerful than the full scale rifle cartridge but more powerful than a pistol cartridge. *note the .30 caliber carbine and 7.92 Kurz have the same length casing, 33mm."

    The .30-06 and the 7,62 Nato use the same diameter bullet, .308" in diameter. While the .30-06 is more powerful, the difference is not that big because the 7.62 Nato is loaded to a higher combustion pressure. The .308 Winchester, the commercial version of the 7.62 Nato cartridge, is loaded to an even higher pressure. But they all use the SAME DIAMETER (.308") projectile.

    The 303 British uses a .311" to .312" diameter projectile, as does the 7,7 Jap.

    The 8mm Mauser round (7.92x57mmJS) uses a .323" diameter projectile. The earlier 7.92x57mmJ cartridge used a projectile of .318", but this was phased out militarily before WW1.

    The 7.62x39 Soviet round (projectile diameter .310") was developed during WW2, but not in general use until the SKS was introduced after the war. The main WW2 Soviet rifle round was the 7.62x54R, shooting a projectile of .310" in diameter.

    The 7.92 Kurz round, the original assault rifle round, shot a projectile of .323" diameter. It was loaded to a higher pressure and design parameter than the 30 Carbine (.308" diameter projectile) itself a rimless, smaller diameter development of the old semi-rimmed 32 Winchester Self Loading cartridge.

    tom
     
  12. KodiakBeer

    KodiakBeer Member

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    It's all very confusing for people who aren't gun nerds like myself. For instance the various .38 and .380 calibers are generally about .35 caliber - .357 for the .38 Special and .357 Magnum, and .355 for the .380 and various other 9mm(ish) iterations. The various .44 calibers are generally about .43 caliber - .429. Confused? Yeah, me too sometimes...

    In the popular media today, rounds fired from "assault weapons" are generally described as doing horrific damage (or whatever), when in fact FMJ military rounds from weapons like the AK or AR cause considerably less tissue damage than any round designed for a standard deer rifle. If somebody gives you a choice to get shot by an AK or Grandads antique .30/30 with a soft point deer load - choose the AK!

    It really is very confusing and answers are difficult to get because the myths have been repeated often enough to become truth.
     
  13. machine shop tom

    machine shop tom Member

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    I shoot and reload several different milsurp weapons and calibers (and others as well). I have .308 Win (7.62 Nato), .30-06, 303 British, 7,63x39 Russian, 7,62x54r Russian, 7.65 Argentine in the 30 caliber range. These shoot bullets in .308", .308", .311", .310", ,310" ., and .313" respectively. My 6.5 Carcano shoots a ,268" diameter bullet, my 7,35mm Carcano shoots a ,300" diameter projectile. My K98 Mauser shoots the 8mm JS round with the .323" bullet, while my M95 Steyr uses an 8x56r cartridge with a .329" diameter bullet.

    But to make things interesting, my Mosin-Nagants (M-44, M-91/59, and M91/30) have barrels that measure .313" to .316" so I use .312" bullets in them, which also work nicely in my Enfield Mk4 and my sporterized 1891 Argentine Mauser.

    THEN there is my 1907 Winchester in .351 WSL, but that's a whole 'nother story.

    Yeah, I'm a gun nerd, too.

    tom
     
  14. Campin' Carl

    Campin' Carl New Member

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    Bit late to the party, also I thought it had been a while so I'll check whats up.
    Just going to input into question 3.
    When looking at bullet stats or what have you you can't just look at the 9mm or 8mm, ect.
    You have to look at the second number that usually comes with that, ei 9x19mm (Parabellum) and 7.92x57mm (Mauser). You asking why the 9mm is less powerful that the 8mm well that's because of that second number, the case for the 9x19mm Parabellum is only 19mm long while the 7.92x57mm is 57mm long, you can hold a lot more powder in the 8mm case, therefore you have more power behind the bullet.
     
  15. lwd

    lwd Ace

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    It would be even more helpful if the second number was the case volume rather than length as the volume can vary considerably for a given length. Then of course one gets into whether or not the weapon can take a high power load safely.
     

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