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#21
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Nele VII wrote:
.... Or, if you want to believe in conspiracy theories, nobody is counting your rounds nor the AK can be traced back to you if you whack someone by accident... or purpose. .... My ops sergeant once told me that in Vietnam his platoon sergeant had kept an AK-47 for the express purpose of shooting any of his own people who fell asleep while on watch. Or at least he threatened to. Whether he actually did was not clear. |
#22
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#23
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"B2431" wrote in message ... | | Generally, just keep in mind the evolution of propellents so modern cartridges | can accomplish higher pressures in shorter cases. Competition shooters are | doing amazing things with ammunition now. | | Dan, U. S. Air Force, retired Only up to a degree. Military ammo may have to sit on the shelf for 30 years or more (I remember shooting 50 cal that was 35 yo), be fired with newer or older batches on the front line and be compatable with the oldest firearms that it's likely to encounter. The major changes were (obviously) black powder to nitrocellulose based propellants, which would be a major advance for gas operated weapons. Since then, most ammo development, _within a calibre_, has been for shelf life and stability, less residue and more consistent performance round-to-round. Cheers Dave Kearton |
#24
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Here is a hadful from my desk drawer
www.regnirps.com/cartridges.jpg Left to right: ..22 Long Rifle ..22 Magnum ..22 Hornet ..223 (5.56 NATO) ..243 Winchester (necked down .308 and proposed US Mil standard) 7.62mm by 39mm (AK-47, SKS, etc) 7.62mm by 51mm NATO (.308 Winchester) 30-06 ..300 Winchester Magnum ..50 BMG -- Charlie Springer |
#25
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"Regnirps" wrote in message ... | Here is a hadful from my desk drawer | | www.regnirps.com/cartridges.jpg | | Left to right: | .22 Long Rifle | .22 Magnum | .22 Hornet | .223 (5.56 NATO) | .243 Winchester (necked down .308 and proposed US Mil standard) | 7.62mm by 39mm (AK-47, SKS, etc) | 7.62mm by 51mm NATO (.308 Winchester) | 30-06 | .300 Winchester Magnum | .50 BMG | | -- Charlie Springer | | Nice collection, you don't have a 'still in the back yard as well ? Cheers Dave Kearton |
#26
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Just in case you aren't confused yet, here's some more trivia. Cartridges such as 44/40 and 45/70 come from the old black powder days. The second part after the slash denotes how much powder was inside the casing and that gives you the size of the casing. It sometimes helps to know the history of the round. Evan Williams "BUFDRVR" wrote in message ... The X number refers to case length. There are several 7.62 diameter rounds out there varying length. 30 carbine = 7.62 X 33, 30-06 = 7.62 X 63. The Russian equivilent to the 30-06 X 54R Thanks to all for the answer. I'm assuming the larger x number, the longer the case and the longer the case the greater the load of powder? BUFDRVR "Stay on the bomb run boys, I'm gonna get those bomb doors open if it harelips everyone on Bear Creek" |
#27
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Bill Phillips
Most people use energy as a first approximation, with bullet design just as important but harder to assess. Bullet behaviour on impact is of decissive importance when assessing the effectivity ("stopping power"). FMJ 7.62x39 tends to be relatively stable on impact in soft tissue, it just turns 180 degrees to leave base first, but does not break up nor tumble more. Thus the 7.62x39 bullet often tends to go through the target relatively cleanly, expending only a fraction of its energy in causing damage. Lighter, smaller calibre, but faster, assault rifle rounds, like 5.56x45 and 5.45x39.5, are much less stable on impact. The higher speed and smaller diameter to lenght ratio, tends to cause lots of tumbling in soft tissue. 5.56x45 also tends to break up, while 5.45 with its bimetal design tends to deform. The higher speed gives a stronger shock wave too. Thus a larger percentage of the energy of these rounds is expanded inside the target, causing more severe wounds at normal battlefield ranges (at long ranges, however, the target effects are much reduced). 5.56x45 is actually _more_ effective against soft tissue at typical ranges than slower full-sized FMJ rounds, like 7.62x51, which tend to go through the target with much of their kinetic energy still left. (Rifling is most relevant here too, eg 5.56 at 1:7 is more stable and less lethal on impact, than the former standard, 1:9). 5.56 is also intrinsically better at armour penetration than 7.62x39, as the surface pressure is larger due to the smaller calibre. Otoh, armour-piercing capability depends a lot on the bullet design, and I dunno how the various dedicated AP bullets compare. Full-sized rounds (7.62x51 etc) have much more kinetic energy, and hence allow for more effective AP rounds. 5.56 and 5.45 have lower recoil than 7.62x39, allowing for quicker/more accurate aimed rapid (semi-auto) fire and better control of full-automatic bursts. This is a big advantage. The recoil of 7.62x39 is however low enough for a competent user to control an assault rifle at auto. In contrast, assault rifles with full-sized rounds, like 7.62x51, are practically uncontrollable at full auto. Muzzle brakes can be used to somewhat reduce the recoil, but at a cost in the signature and/or weight and length of the weapon. The lethality of 7.62x39 against soft targets can be much increased using soft point (expanding) bullets, like hunting bullets, but these are illegal in military usage. I'd guess that a deforming legal(?) bullet could also be developed, perhaps along the lines of the bimetal hollow-tip FMJ 5.45x39.5. Cost would be an issue though. 7.62x39 does have an advantage over the more modern smaller calibres though. It's less likely to be deflected by foliage, and is also more effective when shooting through trees or berms at a target in cover behind. I'd guess that manufacturing issues were the historic reason why the Germans and Soviets went for 7.6* in their AR's, rather than a faster smaller calibre round. Full-sized rifle rounds, like 7.62x51 or 7.62x53R, typically only have an advantage over modern assault rifle rounds at ranges longer than normally useful for an assault rifle. The much heavier ammunition and much larger recoil, make these calibres badly suited for infantry assault rifles. Hence all technically advanced armies use lighter intermediate-sized rounds nowadays. Sniping rifles and GPMG's are another matter, and there 7.62x51 and 7.62x53R still prevail. The particular terrain (typical lenght of LOS) is also an issue here. Otoh, short-barreled small-calibre carbines, like M4, have a reduces muzzle velocity as compared to normal lenght AR's, like the common M-16. The lower muzzle velocity of M4 impairs lethality beyond 100m or so, which is already relevant. Another issue is bullet drop. The faster the bullet, the less there is bullet drop. The relatively slow 7.62x39 does particularily badly here.the bullet drop of AKM (7.62x39) is about 70cm, which makes adjusting the sights or aim necessary at the longer normal infantry ranges (ie up to 300m or so). 5.56 is also superior in this respect to the 7.62x51 at typical ranges. |
#28
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#29
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(B2431) writes: The X number refers to case length. There are several 7.62 diameter rounds out there varying length. 30 carbine = 7.62 X 33, 30-06 = 7.62 X 63. To confuse matters more, even the metric designations aren't always based on the actual exact dimensions, and the same round may have several designations. Eg, 7.62x53R and 7.62x54R are the same round, the rimmed-cartidge (that's what the "R" stands for) full-sized rifle found. The Japanese did this better than anyone. They had at least three 7.7 mm rifle rounds. To be fair one was for a machine gun. The type 99 rifle used another 7.7 mm. It's a wonder more Japanese didn't get killed or maimed by their own weapons. The nambu sidearm was an abortion. The type 99 rifle I own was unsafe to shoot straight from the factory; it has no noticable erosion so I slugged the barrel. The bore is a couple thousandths too big. Dan, U.S. Air Force, retired |
#30
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