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 Posted: Thu Jul 02, 2015 12:33 am
6.8mm Remington, 5.56mm, 6.5mm Grendel, .300 Blackout, 7.62mm x 39mmWeight and efficiencyA key advantage to intermediate cartridges is their light weight in comparison to full sized cartridges, such as the 7.62mm x 51mm NATO. If a cartridge is effective, yet excessive in weight, a cartridge of equal weight or that is far more effective would be preferable. While the general concept of an intermediate cartridge is trading particular aspects, such as power for the smaller size and lighter recoil, it's efficiency, that is it's range, power, accuracy and all other factor's for it's weight is perhaps the key point to any intermediate cartridge. The general purpose of choosing a smaller cartridge was the light weight it afforded, which allowed for more rounds to be fired at the enemy. Since covering fire and misses were the most common use of bullets in combat, a lighter bullet that would be more likely to hit the target at all was considered important, and thus a lighter cartridge that more rounds could be carried of was considered important. Part of the strategy was based on a report found in WWII that the side with the most bullets fired usually won, regardless of the cartridge type. The second was a series of tests conducted with showed that a U.S. soldier with the M16 could carry twice as many rounds as an enemy using an Ak-47, if just the weight of the ammunition was considered, and twice as much as the M14, which showed they could be nearly as effective. Furthermore, the lighter weight and recoil of the rifle meant that it could be drawn to fire more quickly, and was easier to carry in the jungles of Vietnam, and in a broad scale the evolving battlefield where faster, lighter weapon's were becoming more common (such as the Ak-47), which necessitated the development of their own weapon which could compete against these. While the lessened strain on soldier's and logistics for the lighter weapon was a generally considered a solid choice, immediate problems with the cartridge were exposed. Initially, the 2.5 gram cartridges were too light to reach out to long ranges, and they were eventually increased to 3.6, until finally settling on 4.1 after the Vietnam war. The rounds had trouble penetrating common barriers, such as those in urban environments and even jungle, such as cinder blocks, wood, and even glass. The 5.56mm could be stopped by as little as 2 inches of wood, while the 7.62mm x 39mm could penetrate over 8 inches, which meant even with equal cover we were still likely to lose. While switches back to the 7.62mm x 51mm NATO cartridge have been considered, their excessive weight and recoil makes them more difficult to be controlled in successive fire, for average soldiers, and makes it difficult to provide sustained covering fire, due to it's weight. Thus, alternative intermediate cartridges, with substantially more power or barrier penetration, could be considered essential for combat. To at least be on an equal footing to the 7.62mm x 39mm, the Ak-47 which is perhaps the most prolific weapon in the world, would require the same barrier penetration and general stopping power. While the 5.56mm is an adequate cartridge, stopping power, or incapacitiation, particularly rapid incapacitation, is considered to be very important. The purpose of a cartridge is not to kill, but to incapacitate. The target living through the confrontation is irrelevant, stopping the target from achieving their objective, be it killing innocent people or your own soldiers, is considerably more important. While sad that anyone should die at all, if the target ends up in a prison hospital bed instead of dying, the objective is achieved regardless; the overall goal is to stop the target from achieving their objective, which is presumably a bad thing. Thus, not only for survival, but for strategic purposes in general, faster and more effective incapacitation is necessary in modern combat. Overall improved performance is incredibly important. Range and accuracyRange and accuracy are explicabley linked. Accuracy is a feature that is almost universally useful regardless of the cartridge utilized; improved accuracy implies the ability to actually hit the target, which is fundamental to incapacitating or neutralizing a target at all, or making a bullet practically useful. With most modern rounds in general, it is generally accepted that most will not exceed inadequate levels of accuracy for their intended use however, which can make accuracy less important if it comes at the cost of other features. MOA, or minute of angle, is generally considered the common unit of measurement for accuracy; 1 MOA is roughly equivalent to a 1 inch spread at 100 yards, which would be equal to a 2 inch spread at 200, 3 at 300 and so on. A common sniper MOA would be approximately 1 MOA, while the Ak-47 and M16 both possess around 3 MOA or more. While accuracy does matter, humans are in general similarly sized across the world; the average human shoulder length is between 12 and 18 inches wide, or around 15 inches, and the length of a person far exceeds this, making the radial dispersion less important. If a perfect marksmen aims center mass at a target with a 1 MOA weapon at 100 yards, or with 5 MOA, he will still likely have enough clearance to hit the person center mass. Ignoring human error, the gun itself possesses the capacity to hit a human being in a vital area at these ranges, making it's difference in accuracy virtually negligible as far as practical combat is concerned (for a hostage rescue situation, to hit just the criminal or even a target as small as a gun or detonator, higher accuracy would be desired to avoid potential civilian casualties). While 5 MOA is exceptionally poor, it would be adequate for these ranges. At 500 yards however, it would be larger than the average human's shoulder width. With a 25 inch spread, the weapon would produce an area that allowed, even for a perfect marksmen, to miss nearly half of the time, and thus the weapon would require at least double the ammunition to hit the target, and give the probability of perhaps never hitting them. Thus, at close ranges, large differences in MOA only produce minor differences in area of effect, where as they produce far more substantial differences at long ranges. Because accuracy decreases exponentially across range, with a 1 MOA weapon producing a 1 inch diameter circle at 100 yards, and a 10 inch one at 1000, with a 3 MOA being 3 to 30 etc., accuraccies primary importance is determined at range. Pistols for instance generally have low accuracy, where accuraccies as low as 6-8 MOA still allow for accurate shots to center mass (at a person) at ranges of up to 100 yards, and most pistols are generally only designed for use to ranges up to 50 yards. Accuracy is therefore relative; a weapon only needs to be so accurate for it's intended use, at it's intended range. As high an accuracy as possible is ideal, but if the costs, be them financial or in some other aspect of the round are considered, there is a limit to where increased accuracy can result in realistically improved performance; there are potentially diminishing returns for higher accuracy. A 10 dollar round or round that was too large to be fired from an ordinary rifle, even if it possessed 1 MOA, would be too impractical to be worth the shift, if the intended use of the weapon is at 50 yards, and a 3 MOA cartridge would suffice, being only 25 cents and more practical. Accuracy is dependent on a variety of different factors, including the weapon, barrel length, the precision of the action, finishes, and subtle changes to the barrel. It is however, inherently dependent on the cartridge, as well. Match grade ammo for instance is known for being much higher quality ammunition, with higher consistency. The greater the consistency of the ammunition, the more repeatable and predictable the respond will be, and thus the accuracy. This also usually has the added benefit of increasing the reliability of the weapon as well, due to higher quality control, but it is not always the case. The Mk. 262 5.56mm ammunition for instance is well known for having significantly greater accuracy than the standard M16 or M855 round. Weapon's using this cartridge have gotten as high as 1 MOA of accuracy, substantially higher than the M16's 3 MOA. This is not just 3 times more accurate, but 9 times; due to the dispersion over area, and just not diameter, the cartridge is exponentially more accurate the more it increases it's MOA. If it is 2 MOA compared ot 1 MOA, it is 2 x 2 times more accurate, or 4 times more accurate; if it is 3 MOA compared to 1 MOA, this can be considered to be 9 times more accurate, or 3 x 3. While a considerable jump, the Mk. 262 is expensive and requires tighter rifling than most standard rifles, as well as being slightly heavier at 5 grams, compared to 4 to 4.1. The M855A1 Enhanced Performance Round, which is made predominately of copper, is also a very effective cartridge, with a faster burn time more suitable to carbine length weapon's, which can achieve 1.5 MOA from the same weapon's, which is far more than the barely reliable 3+ MOA M855, and additionally has more consistent wounding effects not dependent on fragmentation (which is considered to be extremely variable), and also has better armor penetration. Thus, choosing a different cartridge, by itself, can have a drastically different impact on the accuracy of the weapon, even of the same cartridge type. PowerAlternative Wounding Effects
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Posted: Sun Jul 05, 2015 10:31 pm
Cartridge Comparisons For basic cartridge comparison, there are 6 main key contenders; the 6.8mm remington, the 6.5mm Grendel, the 5.56mm, .300 blackout, 7.62mm x 39mm, and 5.45mm x 39mm. In overall comparison, each cartridge's factor's needed to be weighed and considered; weight, accuracy, power, general efficiency, and finally price. The overall most efficient yet effective cartridge is likely the key cartridge one would want to choose. A balance of all these factors is required, as a heavier, more effective cartridge, such as the 7.62mm x 51mm NATO, or even 12.7mm x 99mm BMG would be more ideal in terms of performance, but impractical due to their weight and size. Thus, to have a weapon suitable for practical performance would require it to be within a suitable weight and recoil, on top of all of it's others features. Ultimately, it's ability to be practically used in the field is the key defining factor of an intermediate cartridge. Coming down to brass tacks, to simply see the performance of each cartridge, it's important to compare various features of each cartridge. Energy, One key thing to keep in mind is that cartridge's with more energy are simply going to have better performance. In terms of barrier penetration, stopping power, reliability and even accuracy, a more powerful cartridge is simply going to be more capable in most respects. From the longest barrel length which result in increased power (increasing the barrel length indefinitely will not always increase the power of the cartridge), the 6.5mm Grendel possesses approximately 2622 joules, the 6.8mm remington 2709 joules, the 7.62mm x 39mm 2179 J, 5.56mm x 45mm NATO 1796 joules, .300 black out 1840 joules, 5.45mm x 39mm 1402 J. The 5.56mm, 5.45mm, and .300 black out all are around or below 1800 joules, while the Ak and above are over 2200 joules. The 6.8mm remington and 6.5mm Grendel are both around 2600-2700 joules, which is 45% more energy than the 5.56mm and .300 black out, and nearly twice as much as the 5.45mm. As a result, the weapon's will have significantly higher performance ballistically. They are also both two of the heaviest intermediate cartridges in the comparison. Obviously a balance of all these factors, be them with energy, weight, felt recoil, and magazine are necessary. When it comes to intermediate cartridges, the single most important factor is weight and recoil. The cartridge that performs the best ballistically will not always be the first choice, as logistical considerations for weight, recoil and size have to be considered. After all, a weapon the average soldier can realistically use is more important than any other single factor, which is why intermediate cartridges are used in the first place. If the smallest bullet possible was desired, various pistol cartridges, such as the 9mm or .45 ACP, or even perhaps the .22 LR would be considered, as they possess substantially lighter recoil than most of the above arounds. A cartridge with tolerable levels of weight and recoil is therefore desired, particularly for a weapon's capabilities. Weapon's that are within a particular range of recoil and weight, are therefore more desirable, rather than a weapon with the lowest recoil and weight. While what the average person can handle is variable, in general the 5.56mm is considered to have light, easily controllable recoil, and the 7.62mm x 51mm NATO is considered to be excessive. At some level, it is also possible to trade certain aspects of a weapon for the recoil and weight, particularly if those aspects can be traded for each other in some way, such as accuracy for weight, or recoil. The 6.5mm Grendel, 6.8mm Remington, and .300 black out can share magazines with the 5.56mm, and they are also easily converted from 5.56mm weapons as well, which makes them easier to use when replacing standard NATO weapon's with different cartridges, such as the M16 or Tavor, which both use the 5.56mm NATO. Consequently, because the bullets are not exactly the same size, these cartridges take up slightly more space, and thus less rounds can be loaded into a similiar magazine. The .300 blackout can hold the same amount of rounds, while the 6.8mm remington and 6.5mm grendel hold 28 and 26 rounds, respectively, in the same magazine. While this is a slightly reduced magazine capacity, specially designed magazines can hold more to bump the weapon up to the 30 round capacities, albeit being slightly heavier and longer. Specialized magazines exist as well for both cartridges, which are not STANAG compatible, but generally more lower profile and slightly wider. The Ak-47 and 5.45mm both also possess approximately 30 round magazines, putting all the cartridges at roughly the same practical magazine capacity, giving them roughly equal sustained fire capabilities. While felt recoil, or recoil that is imparted to the user, is an important factor to consider, it is also the easiest to mitigate or alleviate. While mass, energy, power, and other factors are inherent to the cartridge themselves and fundamentally impossible to change without changing the cartridge in it's entirety, recoil can be handled in a variety of different manners. Muzzlebreaks can be utilized to divert a portion of the expanding gases rearwards to reduce a portion of the recoil of the weapon; they can also be used to help increase the weapon's controllability by reducing the muzzle rise of the weapon, or the tendency of the weapon to go off target, generally upwards, after repeated shots. This difference can be nearly 10-50%, or anywhere from 1/10th to a half of the felt recoil force, depending on the firearm and muzzlebreak. Hydraulic recoil buffers, such as those used on the M249, can also soften recoil by spreading it out over time, to reduce the sudden or instantaneous shock that the user will feel otherwise. A more comfortable firing platform, be it a soft pad for the shoulder, or a more ergonomic grip or firearm in general, can help to alleviate the issues with felt recoil even more. Regardless, the standard felt recoil from similiar firearms, for each cartridge, is 5.45mm x 39mm, 5.56mm x 45mm NATO , .300 black out, 7.62mm x 39mm, 6.8mm Remington, 6.5mm Grendel. In comparison, it is for the 7.62mm x 51mm NATO. The weight per cartridge is perhaps one of the most and practically unchangeable features of each cartridge, and also one of the most important. The 5.45mm x 39mm is per cartridge, 12.3 grams per 5.56mm x 45mm NATO, 16.3 grams for the .300 black out, 16.3 grams for the 7.62mm x 39mm, 17.1 grams for the 6.8mm Remington, and 16.3 grams for the 6.5mm Grendel. In comparison, it is 25.5 grams for the 7.62mm x 51mm NATO. Per magazine it is 1 pound for the 5.56mm, 1.2 for the 5.45mm, 1.28 for the .300 black out, 1.63 for the 7.62mm x 39mm, 1.35 for the 6.8mm Remington, and 1.28 for the 6.5mm Grendel. It's important to note that these are rough figures; the bullet mass can vary depending on manufacturing, design, company, and type. It can range considerably even across the same weapon designs, for the same purposes. Mostly dependent on a change in bullet weight, the weapon's magazine weight is considerably more important; polymer or general lightweight construction can reduce the weight of loaded magazines. The Ak-47, 7.62mm x 39mm steel magazines are nearly 2 pounds, however polymer magazines can be as low as 1.6 pounds or less. Ak-74 magazines, or 5.45mm x 39mm magazines can be as low as .85. This is considerable, as a 1.2 pound magazine is nearly as much as the 6.5mm grendel, which has nearly double the energy, which completely mitigates the advantage of the light weight of the 5.45mm x 39mm cartridge all together. While it varies, this is a rough compilation of standard or widely available magazines, and thus the comparison as a result. Accuracy is another factor that varies considerably. While it depends on the cartridge in question, in general there is an inherent level of accuracy present in most bullet types. Range tends to be more straightforward; while ballistic coefficients can change round to round, in general the size of the bullet, it's caliber, the mass and velocity are more or less inherent to a cartridge, and thus to it's range. While accuracy is explicitly linked to range, usually the effective range of a cartridge based on energy levels and bullet drop will be present. The ideal cartridgeIt's difficult to say exactly which cartridge is ideal for the average soldier. While there are similiar aspects to all of modern combat, particularly regarding infantry, the ideal cartridge and weapon heavily depends on the situation. In close quarters, a pistol round, such as .45 ACP or 9mm may suffice, while possessing the light weight and low recoil characteristic of a pistol cartridge, where as at long range the most accurate round available, regardless of the rate of fire, such as a .338 fired from a bolt action sniper rifle, may be more ideal. While there are specific criteria trying to be met with an intermediate cartridge, the general goal is to have the equivalent of a full sized rifle cartridge, the same range and accuracy, while possessing less recoil and a lower weight to make it more practical for the average soldier. Generally speaking, the ability to pierce light armor, and an effective range of at least 300 yards is considered adequate for a modern intermediate cartridge. The ideal intermediate cartridge is hard to quantify; the parameters for which the cartridges need to meet are hardly objective, largely based on averages and assumptions, and are flexible considering some cartridges may simply possess advantages not usually considered necessary for intermediate cartridges, such as excessively long effective ranges, or the ability to be used from short ranges. While a longer range and a shorter overall weapon are always considered to be advantages, usually these are considered trade offs when choosing an intermediate cartridge; when these options are available, it can radically change the choice of which cartridge to pick, even to fulfill a specific role. Objectively, the 5.45mm x 39mm and .300 black out have the least energy in terms of weight. While lighter magazines are available for the 5.45mm x 39mm and .300 black out, in general they are excessively heavy for their energy levels; while energy is not the only factor to consider, in general not much is gained by their heavy weight. The 5.45mm x 39mm is approximately 1.2 pounds for 30 rounds, while the .300 black out is 1.28 pounds. This is 20 and 28% heavier than standard 5.56mm cartridges, for not much gain in capabilities, considering that they are at or possess slightly less energy. While the .300 black out is heavier than the 5.56mm, and thus potentially more powerful, possessing better barrier penetration or even potentially stopping power, the benefits seem to be relatively marginal in comparison to the cost, particularly considering it decreases the range. Compared to other cartridges such as the 6.8mm remington or 6.5mm Grendel, with far more power, accuracy, and range for the same weight, they seem to be less effective cartridges. While lighter magazines are available for the 5.45mm x 39mm cartridge, trading it's slightly reduced weight for the significant drop in power, barrier penetration and other qualities, when the average soldier likely can carry these rounds without much trouble, seems ineffective. The 7.62mm x 39mm is also substantially heavier than the 5.56mm, at approximately 1.6 pounds per magazine, which while offering more power, is less accurate, has a shorter range, and more recoil. The 7.62mm x 39mm and 5.56mm could in general be considered equivalent cartridges, with various trade offs in capabilities, such as power for weight. With ideal magazines, the 7.62mm x 39mm cartridge is only 32.5% heavier, and thus in theory could be more weight efficient in comparison. The 6.5mm Grendel and 6.8mm Remington are the remaining cartridges. Both possess roughly equivalent weights, although the 6.5mm Grendel is somewhat surprisingly lighter weight. The 6.8mm Remington brass is based on .30 Remington brass, which implies the weapon utilizes approximately 8 gram cartridge cases, and the 6.5mm Grendel is based on the slightly lighter .220 Russian, or the 7.62mm x 39mm Brass, which is generally 6 grams. This makes for a slight difference in weight, somewhat offset by the fact that 6.8mm Remington cartridges generally tend to use slightly lighter weight cartridges, such as the 7.1 or 7.45 gram bullets, and the 6.5mm Grendel uses 7.8 to 8+ gram bullets. Both also possess lighter bullets, but with far less power and range. They are approximately 1.33 and 1.28 pounds heavier, respectively, for equivalent 30 round magazines (although 28 and 26 are their general magazine sizes). Being comparable in weight, they possess substantially more energy than either the 5.56mm or 7.62mm x 39mm, as well as the 5.45mm x 39mm. Both cartridges possess around 23-30% more energy than the 7.62mm x 39mm, and 45-50% more energy than the 5.56mm, at the muzzle. Their bullets are nearly twice as heavy as the 5.56mm, and equal to the .300 black out and 7.62mm x 39mm, which gives them both the firepower of these cartridges, while matching the range of the 5.56mm. Objectively, both cartridges also possess much higher fundamental accuracy than any of the cartridges presented, other than the Mk. 262. While the accuracy can vary based on the firearm in question, the 6.5mm Grendel and 6.8mm Remington consistently get roughly 1 MOA or less in the weapon's they are chambered in, even using standard factory ammunition. While it's possible to achieve less, both in general possess superior performance in almost every category than the cartridges presented, and on top of their raw capabilities they also possess unique features inherent to them. While both cartridges possess an unusually high ballistic coefficient, the 6.5mm Grendel has an incredibly long range. At 600 yards, the weapon possess approximately the same amount of energy as the 7.62mm x 51mm NATO cartridge, and retains higher energy beyond this. The 6.5mm Grendel remains supersonic to 1200 yards, and is generally very effective out to 1000 yards, possessing 540 joules, and better armor piercing capabilities than the 7.62mm x 51m NATO. Price and ProductionIn my opinion, price and production issues are more or less a non-issue. While price is a considerable factor, and production problems could fundamentally halt mass production, none of the cartridges seem to inherently possess this problem. Infantry form the backbone of the U.S. military, and most militaries around the world; they not only make up the core bulk of combat soldiers, but they also are crucial to winning modern conflicts. Whether by sheer size and scope or the need to avoid civilian casualties, infantry can be utilized to provide direct, discriminate fire against the enemies. Both to sweep sectors and hunt down specific enemies and to specifically take down certain targets to avoid civilian casualties. With the increase of low intensity conflicts and an emphasis in urban centers for the new future of warfare, the demands on infantry have increased considerably, and thus providing them with greater capabilities is essential for winning future conflicts with limited civilian casualties. It also doesn't hurt that the U.S. military spends an incredibly small fraction on it's infantry in general; 6.8mm Remington vs. 6.5mm Grendel - Barrel length
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