Ballistics Theory And Design Of Guns And Ammunition Rar
The title of this blog post was mandated by the 196,800 Revolutions Per Minute Marketing Department One of the benefits of having a system that allows me to accurately create cartridges and predict their performance is that I am able to easily make comparisons and evaluate different configurations against each other in terms of weight, size, and performance. I previously used this method to create a standalone cartridge that satisfied Tony Williams' requirements for a GPC in Today, I'm going to use it to create an example cartridge that shows in part why most larger-caliber 5.56 replacements offer virtually nothing over the cartridge they would replace. First, we whip up a 5.56 load with the. Alright, now we have two sets of performance figures that are about as directly comparable as we're likely to get. Now we need to run them through a ballistic calculator, the best free one of which I am aware being the one at JBM Ballistics. This is, in my experience, a very accurate calculator, that compensates even for nonlinear increases in wave drag at supersonic speeds. So we enter the projectile weight, velocity, caliber, and set the maximum range to 500 meters, range increment to 100 meters, zero to 25 meters, and sight height to 1.5'.
We also check 'ranges in meters', and in a dropdown menu select 'Energy (Joules)'. Next, we just need to find some accurate ballistic coefficient figures. Fortunately, which just so happens to include the value for the.277' Hornady 110gr V-Max. For 5.56, we'll derive a ballistic coefficient value with the same form factor as the V-Max, in the interests of keeping everything fair. We get a value of.159 G7, very close to SS109's.158. Now we can get a good estimate of the performance of these two cartridges.
We can see from this that the weight of the cases is very comparable. To get the actual weight of each case, we divide the highlighted figure by 1,000, and multiply by 8.4 (approximately the density of drawing brass). For 5.56, we get 6.372 g, and for our 6.8/5.56, we get 6.298 g. Next, we need to find the weight of the powder charge for each. Well, hey, we already know this, it's right there in the Powley computer results.
Converting to grams by dividing by 15.43, we get 1.458 g for 5.56, and 1.283 g for our 6.8. So far the 6.8mm is winning! There are two more components left. One is the primer. I happen to know that small rifle primers weigh about.25 g, and both are cartridges use SRPs, so we'll add.25 g for both.
The last component is the bullet. We know the bullet weights already; 62gr (4.02g) for 5.56 and 110gr (7.13g) for our 6.8. This is where the 6.8's minor lead in terms of weight gets completely shattered.
Adding it all up, we get a total round weight of 12.1 g for the comparative 5.56 and 15.0 g for our 6.8mm cartridge. Now, if we take the energy at 500m and divide it by the weight of the cartridge, we can truly begin to compare these two cartridges. For 5.56, we get a value of 35.5 J/g@500m. For our 6.8mm, we get a value of.
33.7 J/g@500m. That's right, in terms of energy retained at range for every gram carried, the much-loathed 5.56mm actually comes out 5% better than its 6.8mm counterpart. Who'd have thought? Keep in mind that 5.56 also produces a vastly superior trajectory to the 6.8mm cartridge, having a whopping 81% less drop, 19% less wind drift, and 25% better time of flight, at 500m. Further, remember the principles of wounding when looking at these two cartridges.
Ballistics Theory And Design Of Guns And Ammunition Rare
Not only is the 6.8mm projectile much larger, it is also much slower. Therefore, we cannot expect it to exhibit fragmentation except at the absolute closest range, and even then, it will not do so very dramatically. If it tumbles, it will do so later than comparable 5.56 caliber projectiles, (link begins a download) within a human target. Is this comparison perfect?
No, it makes several compromises in exactness for the sake of clarity. Does it reflect every larger-caliber 5.56 challenger out there? No, but it does give the reader an idea of what effect increasing the caliber and projectile mass and reducing the velocity has on its performance and the overall weight of the cartridge (or, taken in the inverse, one might ask which produces better ballistics, 6.8 SPC or 6.8 SPC necked down to.22 caliber?).
It is unfortunate that this material is too technical to be introductory, as it is so fundamental to understanding rifle cartridge design. Much time and effort that has been wasted might not have been if the designers of these medium-caliber intermediate cartridges had understood these principles. A closing note: This comparison humors the assumptions of many opponents of 5.56 that the amount of energy a cartridge produces per pound carried is the sum worth of that cartridge in combat. One should not confuse my demonstrating that 5.56 meets and beats many of these proposals on their own terms with my validating that method of evaluating cartridge performance for infantry rifles. Much is said of the supposed unreliability of rifles in the AR-15 family. For those who know the rifle only from articles posted to the internet, it's obvious that the weapon is a massive failure. It's fragile, jams constantly, 'shits where it eats', and chokes up completely when exposed to any sort of extreme environment.
Well, that's what I believed once, anyway. The reality of the matter is that the AR-15 is a tremendously well designed, mature, and very reliable family of weapons. My first exposure to how very wrong I was about the AR-15 came when, frustrated by, I broke down and bought the closest thing to a military M4 I could get - a Colt 6920, which I named as a jab at Colt's logo, its high price ($1400 at the time), and what I felt must surely be my own growing insanity.
I shot the weapon and kept shooting it. From the beginning I fired through it almost exclusively, almost begging it to choke, so that I would be proven right once and for all.
I kept pushing it further, firing it in more and more testing conditions, in sub-zero temperatures, covered in dirt, through wind and rain and through some very nasty dust storms in New Mexico. I almost never cleaned it, and it usually saw at least a thousand rounds from the last time before I lubed it. It didn't matter. Nothing stopped it. In the span of about a year, I fired nearly 5,000 rounds of (mostly) steel-cased ammunition through the rifle, and once it failed to lock back on an empty magzine. I never had another malfunction of any kind. After all this, my old opinions of the rifle were thoroughly destroyed.
So, this was the rifle the troops were using. It was a damned good one. Extremely reliable, and accurate enough for me to pluck the highest score three times in a row at Appleseed events. I stretched its legs, too.
Far from the Internet wisdom that says the AR-15 is 'only a 300 yard weapon', I consistently made hits with that same crappy Russian ammo out to 400, 600, and finally 900 yards before it began to struggle. What was all this I heard about the M4 being unsuitable for the fighting in Afghanistan? With the TA01NSN ACOG I'd bought a couple years earlier secondhand, Incitatus had very long legs, indeed.
Later, upon hearing me gush a bit over my rifle, a classmate of mine who had served with the Army in Iraq and had a bad experience with the M16, challenged me to a bet: I would choose the worst of his bringback magazines, and try to fire a full 30 rounds through my Colt. If it didn't malfunction, he'd buy me a pack of beer.
We chose a particularly nasty example that had bent feed lips, was more of a parallelogram than a box, and had broken all the welds along the spine and been re-welded - poorly. It was time for a range trip. Out to the wooded foothills of Colorado, we went. After a long dirt trail, barely traversed by my friend's '86 silver Toyota Camry, we stopped, and broke out our rifles and handguns, and began shooting. I gave my friends a background on the bet, and my girlfriend fired up my handheld Casio camera to record proof.
Through a total of about 150 rounds, in fact. By the end of the range day, I never got the magazine to cause the rifle to malfunction. I've read a lot of forum posts, blog posts, and magazine articles that bash the AR-15. For a while, I was convinced they all couldn't be wrong. I've since learned, not only how reliable an AR-15 can be even through neglect and tough conditions, but also not to jump to conclusions based only on an opinion I read somewhere.
Having said that, I'll leave you with a few blog posts and online articles that buck this trend, and talk about the virtues of the AR-15. First there was the in the 1930s, then there was the in the 1970s. Now, in the oughts and teens of this century, we have a How droll!
On every corner of the military-related internet, it seems, one will be assailed by true believers who assure you that the 5.56mm and other small caliber high velocity cartridges are the products of a failed concept and must be replaced by something else, which inevitably must be much heavier and greater in caliber. This post will - unlike the last which addressed Mr. William's article specifically - be a more general response to the Caliber Mafia, incorporating a number of ideas mentioned in Each section will address common arguments made by mafiosos, both those critical of 5.56mm and in favor of larger caliber cartridges. Higher performance is attainable using modern powders This argument is often used in concert with predictions of extravagant performance of a pet cartridge. For a start, propellant technology has been fairly stagnant for the past half a century. In addition, the energy density of the propellants has not improved much.
Further, because the energy of the projectile is produced by the pressure curve of the propellant, gains basically cannot be made without slower burning propellants, and that only works up to a point, limited in military use by muzzle flash and muzzle thrust (the hypothetically ideal 'plateau' burn curve can only be achieved by introducing more propellant into the combustion chamber after ignition has begun), as well as the practicality of loading large quantities of such ammunition quickly. As an example of how an improvement in velocity implies a rise in pressure, when nitrocellulose powders were introduced in the late 19th Century, the performance of cartridges of a given size greatly increased, but so too did the average peak pressure. Expecting significant gains in performance against historical cartridges without increasing peak pressure will thus leave one disappointed. The cited quote from Mr. Williams is a particularly good example of this, as he simply ignores several important factors in making this statement. For instance, the 6.5x50SR Arisaka produced between 2,500-2,600 J with an 800mm barrel, which is 60% longer than the barrel length prescribed for the GPC (20'/500mm). Williams makes a mistake in assuming that my statement at the end of was a predictive one; it was, rather, observational: It is highly unlikely that a cartridge will produce performance greatly superior to the 6.5 Arisaka from a significantly smaller cartridge if it is constrained to 20' barrels, even if it is using current propellants and pressure levels.
5.56mm weapons are dead weight in long range engagements In fact, the last time this wasn't true, rifles came issued with volley sights and riflemen massed up in large formations, doing their best impression of a couple of mortar teams. The idea that a new caliber will change this seems a bit optimistic to me.
There is a conversation worth having about the the increase in effective range of infantrymen from 300 to 500m brought about by the introduction of. However, one should also consider that which current-issue M855 ammunition improves upon considerably. A tentative conclusion that 5.56 is well-suited to 500m combat is thus reasonable. Terminal ballistics is too complex for science So help me god I've actually had to address this argument. Scientific inquiry is capable of producing far, far more complex deductions than those asked of a simple ballistics test. Laboratory experiments have been conducted that boggle the mind in their precision and control for numerous variables.
To claim that a quantification of terminal effectiveness is 'beyond science' is simply ludicrous. For posterity, I will re-post my suggestion for an experiment here: Shooting at live, restrained pigs connected to sphygmomanometers, heat rate monitors, ECG machines, and EEGs, counting only precise shots accurate to within a tolerance (determined by a medical professional) on a target area of the body (this could be the heart, brain, an artery, or lung, etc), a number of different rounds of ammunition, controlling for a variable (e.g., projectile weight or muzzle energy) are fired.
The results from the devices are then measured and evaluated by medical professional of that specialty as well as veterinarians. Rinse and repeat for each variable you need to isolate. Larger caliber cartridges are more effective, this expert doctor says so This follows from a misunderstanding of the term 'wounding' as used in the medical sense, and a conflation of higher energy cartridges of 7.62mm caliber (such as.30-06) with lower energy cartridges of the same caliber (such as.30 Carbine) on the part of both doctors and the readers of their research. The difference between wounding as is relevant to the medical profession and incapacitation is explained in A word about Dr. Martin Fackler: is often used to support arguments that only the permanent cavity of a wound channel matters for incapacitation, or that it matters the most. He himself does not say this anywhere, so far as I know. Fackler, instead, addresses (among other things) the notion that tissue around the wound in high velocity gunshot wounds needs to be excised for treatment.
His studies show that the tissue damaged by the temporary cavity will recover, and that energy deposition has no effect on treatment, saying nothing about incapacitation. Doctors, obviously, are concerned with the former, while small arms designers are largely concerned with the latter. 5.56's terminal performance is unreliable; a larger caliber projectile will produce more consistent results This is an argument I see implied almost any time the subject is brought up. Evidence of inconsistent terminal effectiveness in 5.56 is provided, and thus 'we need a new, larger caliber' to fix it. If one is limited to Hague-compliant projectiles, then tumbling and fragmentation will be your primary vectors for terminal effectiveness. Not only do larger calibers (all things being equal) tumble less readily than smaller ones, they also often don't have enough velocity to fragment consistently. 6.8 SPC FMJBT bullets, for instance, hardly fragment at all, even at very close range.
The implied notion that, despite this, an additional few hundredths of a square inch frontal area will drastically improve effectiveness leaves me a bit skeptical. M855 fired from an M4 fragments out to only 50m The response to this is very nuanced and complex, and thus wholly unsuitable for the type of soundbyte-based debate that occurs on internet forums.
While the fragmentation of small arms projectiles does change with the velocity at which they impact, use of the term 'fragmentation threshold' can be misleading. If a projectile is fired at just below the fragmentation threshold, it performs much the same as if it is fired just above. The fragmentation threshold thus does not denote a drastic transition in performance of conventional jacketed small arms projectiles at a certain impact velocity.
It is useful only in eyeballing how the projectile performs at different speeds, as at speeds below the threshold, no fragmentation occurs, while at speeds above it, fragmentation occurs in progressively more severe fashions. Only at very high velocities (typically over 2,900 ft/s, depending on jacket construction) does the familiar 'confetti' fragmentation pattern occur. The reader should also keep in mind that fragmentation depends on many factors, the most important of which, besides impact velocity, is the construction of the bullet. Some materials fragment at very low velocities, while others may fragment only at velocities above that which is practical for nitrocellulose propellants. The figures used here are a 'rule of thumb' for jacketed, lead-cored bullets, but even within that scope they can differ significantly from reality.
I am going to try to make this as brief as I can, but this section of my response is fairly technical and involved, as it covers a 'worst case' scenario for velocity at range for the M4 Carbine in some detail. A military barrel is considered to be worn out if it experiences a velocity loss of 200 ft/s or more vs. A new barrel. The standard set in defines the average velocity of M855 from the M16A2 to be 3,000 ft/s (+/-40) at 78 feet from the rifle, which equals an average muzzle velocity of 3,081 ft/s. From the 14.5' barrel of the M4 Carbine, we can expect no more than a. for an average muzzle velocity of 2,811 ft/s. That gives us a muzzle velocity from our unserviceable barrel of 2,611 ft/s.
Now, we can plug this figure into a ballistic calculator and see if our commenter is right. I am using the above velocity (2,611 ft/s), a zero range of 25m, a maximum range of 500m, a range increment of 1m, and. The result is that the bullet reaches minimum fragmentation velocity at 154 meters. If a threshold of 2,300 ft/s is used (which I've seen quoted a few times), then it reaches that velocity at 101 meters.
Only if a threshold of 2,500 ft/s is used does the fragmentation range drop below 50 m. This is not the minimum threshold of fragmentation, but the upper bound minimum velocity at which the jacket may split along the cannelure.
Keep in mind, an M4 that clocks velocities this low is considered unserviceable and should be removed from service and fitted for a new barrel. If a more reasonable velocity of 2,970 ft/s.
is used, the M4 Carbine stays above the 2,140 ft/s until 260 m, and above 2,300 ft/s until 207 m. Even if a threshold of 2,500 ft/s is used, a muzzle velocity of 2,970 ft/s gives a fragmentation range for the M4 of 143 m.I don't think SADEF's figures are representative enough to be used outside of the scope of their experiment. The test was interesting, but I don't really think 9.6% velocity reduction is an accurate figure for the velocity loss going from 20' to 14.5' barrels (it results in approximately 50 ft/s lost per inch!). However, I'm using it here as a 'worst case' example.
Provides a more reasonable muzzle velocity figure for the M4 of 2,970 ft/s, which is a loss of about 25 ft/s per inch from the M16's nominal muzzle velocity of 3,100 ft/s.I use a minimum fragmentation velocity of 2,140 ft/s, which is close to the lowest velocity at which fragments will come off of the bullet (usually shed from the lead core). The picture used as an example of this is of M193, but M855 performs basically the same way at comparable velocities, having the same jacket thickness. Note: There are a lot of different figures thrown around for the muzzle velocity of the M4, both in this section of this post and elsewhere on the Internet. While it may be desirable to keep a nominal muzzle velocity figure for a given rifle and ammunition on hand, one must remember that many factors affect the muzzle velocity of a rifle, beyond the type of ammunition fired and the barrel length of the gun. Such factors include - but are not limited to - the temperature of the ammunition just before firing, the profile and contour of the bullet, the shape and dimensions of the rifling, and the wear on the barrel. I took considerable effort to use the lowest velocity figures that seemed reasonable to me in every instance, to try to weigh the examination in favor of the idea that the M4 has a critically short fragmentation range. For example, FM 3-22.9 gives the muzzle velocity of the M16A2 as being 3,100 ft/s, not 3,081 ft/s (calculated from the specification in MIL-C-63989C).
Even so, I was only able to achieve a fragmentation range of 50m by using a very high fragmentation 'threshold' of 2,500 ft/s. 5.56 relies on fragmentation to incapacitate M855 and M193, like all military rifle projectiles, This is why ballistic gelatin is such a good indicator of performance, especially if high speed video footage is taken of the shot. At high velocities, 5.56mm FMJs will fragment, which can cause very grievous wounds indeed, but even if they do not fragment they will still tumble and deposit energy. Further, the single biggest factor in incapacitation is shot placement.
It is unlikely that any 5.56mm projectile will incapacitate the target with a shot to an extremity, but As noted before, and thus will tend to deposit a greater percentage of their energy into the target. 5.56 produces only 2,700 ft/s from the M4 This is based on using a nonstandard barrel, with ammunition chilled before firing for temperature consistency. It is not applicable to M4s with good condition barrels used in temperate conditions, which typically have muzzle velocities about 200 ft/s higher or more. Permanent cavity is the most important factor in incapacitation disagrees. 'Stowed kills'.
This is the way I have seen the term 'stowed kills' used in small arms circles (it is used in a completely different way when talking about AFVs): the speaker describes (explicitly or implicitly) some sort of modifying coefficient to ammunition. E.g., it has been argued that 6.8 SPC is 3.5 times effective as 5.56, and weighs 40% more, therefore it is overall 2.5 times as efficient as 5.56. I argue that this is nonsense. The reason being that very few rounds fired from infantry rifles ever hit their intended targets. Most infantrymen who've seen combat have not shot directly at another person very many times at all. I would hazard a guess that the number of enemies hit by ammunition fired from rifles in combat per combat veteran rifleman is decidedly in the single digits, and may even be less than one (I'm being extremely generous here, given figures from past wars). The number of rounds expended per combat veteran rifleman, however is assuredly much higher, probably in the triple digits bare minimum.
Let's go with some ballpark figures. Say the average combat veteran rifleman expends 5,000 rounds of ammunition over his combined tours of duty, and hits and at least wounds 2 enemies in that time. That means, if he was using a 5.56mm rifle, he would have expended 60 kilograms worth of ammunition, only a few tens of grams of which had any physical affect on the target at all. Nearly 5,000 rounds he expended, minus the ones fired that hit their targets, produced exactly zero kills. Only a handful of cartridges were directly responsible for taking the enemy out of action, so even if a more poorly-performing caliber is used which requires a soldier to fire many more rounds to incapacitate a target, that fraction of the total rounds expended over that soldier's tours in terms of weight is still very small. This will be true regardless of whether the cartridge is 5.56mm, 7.62mm, or anything else. Therefore, 'stowed kills' as it is typically used in the context of infantry rifles, is not a useful metric.
Twist rate has no effect on the terminal effectiveness of 5.56mm This unfortunately results from a misunderstanding of how a bullet travels in flight. It is true that a bullet spun by rifling cannot hope to remain stable for long in a mostly-water medium like tissue or ballistic gelatin. However, this is not the only factor in how and at what point in its travel the bullet will tumble.
The twist rate of the barrel helps determines the stability of the projectile through media, in this case air. A tighter twist rate will better stabilize the projectile, reducing the of the bullet (the degree to which it deviates axially from the flight path). It is this reduced angular deviation that can cause through-and-through wounds, not the bullet being stable through flesh.
In other words, than one stabilized by a 1-in-9 twist rate barrel. I highly suspect this is why you will be hard pressed to find a gel test video online of M855 being fired from a 1-in-9 twist rate barrel and failing to upset within about the first 5'.
Somewhat paradoxically, this tight twist rate should give M855 exceptionally consistent long-range terminal effectiveness. The same excellent stabilization that minimized precession also ties the bullet more closely to its original orientation through its flight. That means that at long range the bullet is flying through the air at an upward angle relative to the arc of its flight. If it hits a target at this angle, it should upset readily and tumble within the first few inches of tissue. EDIT (3/23/2014): It seems I may be wrong about this. A closer reading of shows that in testing longer projectiles which would have been less well stabilized than M855 from 1/7 twist barrels, they found virtually no difference in fleet yaw from M855 and any other caliber tested, including M80.
The reason for this erratic performance is that within 50m the projectiles have not yet settled into stable precession caused by their rifling (something I am wholly unqualified to describe). More on this While the AR-15.com explanation of twist rate's effect on lethality is still incomplete, it seems my theory wasn't quite on the mark, either. I am leaving the incorrect explanation up as a record of my mistake. The GPC concept was formulated in light of experiences in Afghanistan, which inclines me to believe that he has come up with requirements to suit his concept, and not the other way around. Regardless of the merit (or lack thereof) of the GPC idea, it is clear that it was not developed in light of recent experiences overseas. Soldiers are unhappy with the performance of 5.56 Soldiers may be unhappy with many things, but there's no reason to believe the performance of 5.56 has not been satisfactory. Have commented on their satisfaction with the cartridge, noting especially its light weight.
Corroborates its effectiveness in skilled hands, even at long range. Given this, it is somewhat strange to be met with constant cries of 'the soldiers don't want it!'
Which cannot then be corroborated with actual sources, anecdotal or otherwise. Often that support the idea that 5.56 is inadequate are implied to exist, but when asked to produce these reports,.The ammunition used here is the 77gr Mk. 262 special purpose ammunition, not M855. At 800m, neither projectile fragments, but both tumble readily. EDIT (3/6/2014) XIV: 5.56mm produces inadequate suppression effect for an infantry rifle cartridge Mr. Williams has become quick to claim that 5.56mm produces inadequate suppressive effect - by way of a small sonic boom - and that a 6.5mm weapon would do much better. What this ignores is how sonic booms are actually generated, and what aspects of a radially symmetrical body enhance or mute the boom.
Fundamentally, the boom is created by the pressure wave, and is closely related to how drag operates on the body itself - which is more a function of shape than size. I'm don't have an Aero/Astro degree, so I can't really go into detail here, but it's important to note that while larger bodies do create larger sonic booms, a.264' bullet from a GPC is simply not bigger enough than a.224' bullet from a 5.56mm round to make an appreciably larger sonic boom. Further, a center piece of the GPC concept is the use of elongated, low drag bullets.
These bullets, for exactly the same reason that they retain energy well, to those that have inferior ballistic shape. The energy for the sonic boom can only come from one place: The projectile itself as it moves through the air.
Therefore, lower drag bullets will necessarily produce smaller, less audible sonic booms than higher drag ones; they simply do not expend as much energy in flight. One way that the GPC could potentially produce louder sonic booms is that it retains velocity better, which is a major component in sonic boom generation. However, the GPC only exceeds the velocity of 5.56mm (when fired from comparable barrel lengths) at 250m, and 5.56mm only becomes subsonic at 700m, meaning the gains in this area may well be negligible. Overall, the biggest problem with Mr. Williams' theory about the sonic boom-producing ability of the GPC is that he has provided no direct evidence for it. Further, the overwhelmingly most important factor in the suppression of enemies is how close the bullets impact to the target. The round that an infantryman will miss less badly with is the round he can carry and shoot without tiring for the longest, given an adequately flat trajectory.
In Sum: There is not sufficient weight to the arguments of the Caliber Mafia to compel me to take their ideas seriously, much less for any military to actually implement any of their proposed calibers as standard issue. While the 5.56mm caliber and the two-caliber system may not be ideal, it is sufficient to meet current needs, so far as this author can tell.
What does the future hold? Whatever the next infantry rifle cartridge is, however.
So you want an AR-15 for hog hunting that can launch.40 cal (10mm) pills? This caliber might be what you are looking for. It is called.400AR and was developed for hog hunting. The designers had initial requirements to have the largest caliber that will allow having double stack loaded ammunition in magazines fitting into the AR-15 magazine well. They also wanted to have at least 2,000 ft-lbs (2,712 joules) of muzzle energy and be able to use one of common cartridge head sizes which would allow using an off-the-shelf. The new cartridge also had to have a maximum pressure manageable by the AR-15 platform. The development of this cartridge started three years ago with the first chamber cut back in the summer of 2014.
The designers came up with a.40 caliber cartridge which is based on 7.35x51mm Carcano case. Initially, they cut the Carcano case right below the shoulder which gave them a 1.6″ long case.
However, later they changed the design and made the final case to be 1.7″ long. The Carcano case has head (.447″) dimensions identical to that of 7.62x39mm cartridge, which means that they could use 7.62x39mm or 6.5mm Grendel bolts.
1.6″ and 1.7″ cases They started they tests with 200 gr.40 cal muzzle loader bullets and after a number of tests, they reached the set goals. The.400AR final load launches the 200 gr projectiles at a muzzle velocity of 2,312 fps with 2,374 ft-lbs of muzzle energy (at around 50K PSI of pressure). It also reaches pretty interesting numbers with.40 cal handgun bullets. Particularly, it pushes the 135 gr bullets at 3,042 fps. I think the same results could be achieved if the cartridge was based on a.422 head size (.30 Remington, 6.8 SPC etc). But that would be a straight walled case whereas.400AR should have a slightly tapered one, which is good for feeding reliability. If the case taper is ignored, then they could use larger projectiles of.423 cal from.404 Jeffery cartridge with the.447″ case body diameter.
But then again case taper is good and the.423 is a rather odd caliber compared to the 10mm/.40 cal. There is a website dedicated to this cartridge, where you can read more about it by clicking.
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No collection can be complete without every variations of that case, and/or bullet size. My guess is most wildcats are created and used by people who are in reloading near the upper skill set level. Where creating something is part of its reward, with greater self satisfaction if it catches on.
I wonder Pre-internet, how many wildcat cartridges were created flourished and then linger before disappearing? Only to be created in different region of the country(or world) and cycle the same fate. The one upside on reading old gun magazines is seeing the wildcat cartridges debates and knowing the historical outcomes.
Makes these debates a little funnier with not cost or skin off our backs. The 6.5g has very good ballistics from short barrels. 7.5 Bartlien at 100 Yards. Groups averaged 1.5 Inches 2000 FPS 123 Match King 8.5 Bartlien at 100 Yards.
Groups Averaged 1.4 Inches 2100 FPS 123 Match King 10.5 Bartlien at 100 Yards. Groups averaged.9 Inches 2200 FPS 123 Match King 12.5 Lilja Blank Chambered by PF at 100 Yards. Groups.75 2300 FPS 123 Match King 14.5 Lilja Blank Chambered by PF at 100 Yards. Groups.5 2350 FPS 123 Match King 14.5 Krieger at 100 Yards. Groups averaged.38 2375 FPS 123 MatchKing Alexander Arms 12.5 inch 6.5mm Grendel Alexander Arms 100 grain Berger OTM 2470 Alexander Arms 123 grain Scenar OTM 2330. Well, i was already reloading for.50BMG and.45ACP, so i thought, “I really want to get into this wildcatting craze for the AR-15.” Still trying to get someone to cut me a chamber, but this is what i came up with.
What the hell always room for another AR caliber, right? It’s a 750 grain.50bmg on top of a.45acp, flared case. Haven’t figured out how to get the bullet through the chamber, yet, but hey, can’t be any tougher than coming up with a large caliber that will double stack, right? Terminal ballistics are perfect for annoying hogs out of a test piece of 1/2″ iron pipe, i got 112 fps with 5.6 grains of 231 and a large pistol primer. Added bonus, you can measure the velocity with a baseball radar system.
I was expecting some sources or something to back up your assertion. Regardless, it’s completely true. 100% copper.40S&W bullets can be propelled at 2000fps without shattering out of the barrel. Considering copper is significantly less dense than lead (most other jacketed bullets), then I doubt that a mere 2000fps would spell the doom of a copper-lead composition bullet either. However, I’ve never been one to disbelieve the results of actual tests that disprove my opinions. Baseless assertions?
Actual experimentation? A 60gr.400 diameter projectile has a sectional density of.053. Even if the constriction is monolithic copper, the bullet will shed velocity so quickly and penetrate so poorly past 50yds that it is completely unsuitable for hunting anything.
On the other hand It is widely documented that most.40 caliber defensive use projectiles when pushed over the designed velocity envelope fail to perform as designed. Shorter penetration, excessive expansion resulting in jacket fragmentation/ separation.
None of these characteristics are wanted in a handgun velocity projectile. Here’ s a pic of a 165gr Gold Dot with the bonded electroplated jacket separated from the core. Not out of the barrel, in the target. Lead has negligible elastic yield strength compared to copper, that thin copper jacket is all that’s keeping it together, so when it hits its target, that jackets going to peel clear off in the first inch and the lead is going to rapidly fragment to create a relatively shallow crater wound.
Even at slightly lower than 2300ft/s velocities, using copper-jacketed HPs designed for 1400ft/s makes the bullet expand too fast, leaving you with greatly reduced pentration. Those people using dogs, arrows and spears were the nobility and owned all the lands, allowing them to go hither thither and yon in pursuit of prey. Private property owners today have the right to exclude others, and charge–handsomely it would seem–for the privilege of hunting on their lands. It is so lucrative it appears that some owners actually stock hogs. Add to the issue is that the natural predators such as wolves are gone, and the only large predators are men.
Until Texas declares hogs a nuisance and orders bounties, the hogs’ scourge will continue if not increase. Even we can’t round up “all the king’s horses and all the king’s men” anymore to stamp out the agricultural menace that feral hogs have become, why isn’t the government already offering bigger incentives for more hunters to bring down what the hog traps can’t? The government could also step in and say that “stocking” hogs is illegal since it means they’re free to breed and repopulate, which is counterproductive. Maybe it’s time to “sound the horns” and bring in enough manpower to put the problem down for good. Even a bunch of people with muzzleloaders could do the trick if there were enough of them, and donating unused meat to charity would be a good use of the unwanted hogs. As for charging too much for the privilege of hunting on private land, we’re dealing with an invasive agricultural pest that doesn’t respect borders and causes lots of damage anywhere it can find food. Sounds like the laws regarding this could be changed for the better.
I can see how this wildcat might get some interest from the 10mm crowd who want to put even more juice (case capacity) behind their.40 caliber bullets, while still being able to handload the same bullets into the shorter 10mm Auto cases for handguns/pistol caliber carbines. However, since.40 caliber bullets don’t have anywhere near an optimal ballistic coefficient due to their short and relatively wide shapes, some of that extra case capacity in this.400AR wildcat will likely go to waste just to overcome drag after the bullet leaves the muzzle. It also means that the effective ranges for these rounds are probably going to be shorter than expected for a rifle-sized caliber with that much case capacity behind it, because the drag means it will lose velocity more quickly than most commonly-used rifle rounds. At closer ranges, 10mm Auto hollowpoints that work well out of handguns or PCCs are likely to have too much velocity when loaded into this wildcat to expand at their intended depths, and will just fragment to produce shallow “splash” wounds.
On the other hand, if used at relatively short ranges (for a rifle round) and loaded with non-expanding ammunition that has a good flat nose, you’d get the same barrier-blindness and anti-windshield capabilities that full-power 10mm Auto is known for, just at an increased effective range. The above concerns wouldn’t be too difficult to address with new 10mm projectiles made for this case, however. With all the room available, you’d be able to make a true 10mm rifle projectile, with the standard spitzer tip and boat-tail to reduce drag and increase sectional density for possible military applications. If the.400AR design team goes down this route to develop the full potential of this caliber, the results will probably be the most interesting developments of this wildcat. Even without making new projectiles, this looks all-in-all like a promising attempt to realize Jeff Cooper’s “Thumper” rifle concept, but with more magazine capacity than previous attempts like the.450 Bushmaster or.458 SOCOM cartridges. Sounds good in theory and the numbers are impressive but there is a distinct shortage of 10mm bullets capable of living at those velocities.
The 135gr reference is nothing short of a joke because they come completely unglued at 1600fps. None of the existing 180-200gr jacketed bullets will do much better and at these velocities, you’re really pushing the limit of a cast bullet. What is needed is a good 220-250gr solid copper or controlled expansion jacketed bullet. The former would still be useful in handguns, the latter, not so much. What you say has a lot of merit, but how far did that chunk of lead travel with the gold dot. I understand there is a limit at which complete destruction takes place, but the best one shot stop statistics was the 357 mag with a 125 gr hollow point bullet.
I believe that was due to the fragmentation of the hollow point bullet and the lead lower continuing through the media. So there is a point which the bullet comes a part but is not a total destruction like a small grain bullet out of a 22 250, going over 4000 fps. If there is a big enough lead chunk it would seem to me that it would deform but continue penetrating. I can hardly wait to do some water trials on some of these just to see what happens. You could stick with solid non-expanding bullets to start. If there’s enough interest, someone could probably make an expanding soft-point for this wildcat. But you’re right in the sense that it would take a new.40 caliber projectile, likely a more rifle-like one with a spitzer tip and a boat tail, to take full advantage of this new case.
As for its double-stack capability, some people like more chances in their box magazines, or need to put down as many members of a herd of feral hogs before they all scatter into the brush. Even shots from a suppressed firearm or well-placed arrows/bolts don’t do anything for the scream of pain from a hog that’s been hit, or the sound of it flopping on the ground, which can send the rest of the herd running for cover. Of course ammo is not easy, it’s a friggin’ wildcat. It’s also being developed by individuals, not a company, so it’s not a “proprietary cartridge”.
You obviously don’t know what these terms mean so I have to question your “in depth analysis”. Energy is about the poorest measure of a cartridge’s effectiveness. It places far too much importance on velocity, too little on mass and zero on diameter. Look at all the handgun rounds that produce significantly less energy than your.308 but have been used effectively against all dangerous game in the world. Sorry but energy is not a useful number.
And the.400AR fits into a standard AR-15. The.308 is restricted to the AR-10 sized platforms. The.400 is also a better solution for subsonic/suppressed use.