Tuesday, May 13, 2014

Are U.S. Soldiers Dying From Inadequate Weapons? No.

I dislike doing rebuttal posts. The temptation is strong to adopt a simple quote-and-refute style, which costs little time and allows me to return to my only modestly interesting but very necessary daily life. This style is only compatible with lazy writing, however, and it's bad form to use it too often. Even so, there is a need for a direct response to some works of "journalism" which rely on sensationalist headlines over content to get attention, and which spread falsehoods, misconceptions, and sometimes even outright lies in the process.

I was asked by a friend what I thought about this hit piece on the M16/M4 platform and the 5.56mm caliber, which I decided offered me an opportunity to write a little more about the subject. As if anyone felt I hadn't already written enough, that is. Interestingly, the piece was written by Tom Kratman - a name I had to google - who is apparently a veteran of the 5th Special Forces Group and of 19 years in regular Army, eventually retiring at O-5 (the same as my father, of a different branch, coincidentally). He also writes science fiction for Baen, the same publisher where the old THR (a major haunt of mine, once upon a time) moderator Larry Correia now writes.

Kratman is then no neophyte as a writer or novice to military thinking, but this in my opinion only lends a hue of bafflement to his two EveryJoe articles. This man was special forces, and an officer, I must keep reminding myself as I read every tired myth, regurgitated piece of gunwriter hype, and mis-remembered factoid.

It is difficult for me to not be critical of the pieces, both from a factual and a writing standpoint. When my inner monologue reads the figures on my liquid crystal display, I am taken back to caffeine-and-pizza fueled spring mornings and afternoons, sitting in one piece chair-desks intended for the tiny Japanese furniture maker who designed them while listening to a youth who hasn't yet learned to shave the few wisps of a Van Dyke growing on his otherwise newborn face wring out a thin argument he decided on a week before. "Write something we can sell," I wonder if that phrase was ever uttered aloud or transmitted via electrons down copper wires during the planning phase of these two articles. Or perhaps Mr. Kratman truly believes in his premature ideas, which are so poorly supported they are in free-fall, about to reach terminal velocity.

"Remember, he was in 5th Special Forces Group, and a Lieutenant Colonel," again.

Let's step back. Many people disagree with me regarding my opinions of the AR-15 rifle family and the 5.56mm cartridge especially. Some of those people, I can hold a discourse with, and present the evidence I have for my position as best I can, to reach a mutual understanding of ideas, experiences, and views which led our opinions to where they are. Some I cannot, because they are too used to fighting the good fight; too zealous for a true mutual discourse.

Many more are too wrapped up in thin premises fed to them via casual reading of the latest issues of tactical magazines in the Barnes & Noble to really have a decent conversation with. It's this last kind that Mr. Kratman most closely resembles, from his escape-velocity exaggeration of the differences in capability of the M4 carbine and M16 rifle, to his mis-placed snark about the vagueness of the ACR program from the 1980s and 1990s. This last plays off an assumption that isn't true - that the ACR program demanded a deliberately vague "100% improvement" over the M16, begetting the almost laughably inane comment: "That means that we will never have a rifle that’s 99% better." In truth, the ACR program's goal was very specific: The winning rifle had to demonstrate a 100% improvement in hit probability during a highly sophisticated course designed specifically to measure that factor with soldiers under combat stress.

None of the rifles even came close. None of the advanced concepts, not burst fire, not caseless ammunition, not four power optical sights, improved the probability of a hit anywhere close to 100% over the M16A2 rifle. Those design elements that did significantly aid the hit probability - most notably optical sights - were incorporated into future AR-15 pattern service rifles and are in use today. To Mr. Kratman, however, the M4A1 with laser, CCO, vertical grip, and light might as well be an M16A2. The degree to which this is true is irrelevant - A G11 might as well be an M16A2 in terms of hit probability, something that Mr. Kratman ignores in favor of the white-noise-esque "they're failing our boys!" drone.

Kratman rounds out the article with more sophomoric whinging dressed as snark, and an off comment about the French. "A Lieutenant Colonel and veteran of the 5th SFG..." Yes, of course, I mustn't forget.

His follow up begins by repeating another half-truth about the M16; that the Army never wanted it and it was all McNamara's fault, a "fact" that ignores that the Army agreed to cancel M14 production in favor of the extremely ambitious SPIW, and McNamara was forcing them to, you know, actually provide rifles to the troops in the meantime. It may be presumptuous of me to think that this is something armies are expected to do, but I'll risk it. Eventually, SPIW crashed and burned, and the surprisingly good M16 became the mainstay of the Army for a half-century. None of this matters to Kratman, of course, since it doesn't make for good copy.

Where some sensationalist gunwriters would take a "back to basics" tack, and suggest re-adopting the M14 in .280 British or some such nonsense, Kratman instead talks about some potential technological improvements that could be in the pipeline for small arms, along with a number of other things that rifle salesmen want you to believe are technological improvements, but actually aren't. His list goes: 1. Intermediate-intermediate calibers, 2. Hyper burst, 3. Carbon-fiber barrels, 4. Electronic ignition, 5. Plastic cased ammunition, 6. Caseless ammunition, 7. A gas piston operating rod, and 8. Optical sights. 2, 3, 4, and 5 fit in with potential technologies that could improve the rifles of the future, 1 and 7 mostly sell rifles, not really offering anything over the 5.56mm cartridge and the AR-15 platform, 6 is all but dead due to technical issues, and 8 has already been implemented, further calcifying my suspicion that Mr. Kratman's technical knowledge of the subject is stuck in 1991.

What's strange is that he doesn't use this list to paint a rosy picture of the future of small arms in contrast to its oft-claimed stagnation; he uses it (in yet another attempt) to bash the M16. As if, somehow, they could have issued rifles then in 1964 that utilized technologies that are just now maturing to a basic level of feasibility. Some early AR series rifles did trial composite barrels and carbon-fiber handguards, features subsequently deleted in later versions because they didn't work very well then. It's as if Mr. Kratman doesn't understand that just having a working prototype doesn't mean you can make ten million rugged, mature, combat-ready weapons.

"A Lieutenant Colonel and veteran of the 5th SFG," I must remind myself.

It's bizarre to read a piece so sophomoric and poorly researched and constructed, only to follow the authorship trail and read a biography that impressive. Simply put, while I do not demand that everything I read reinforce my own opinions and ideas, I do not expect this sort of thing from a Special Forces Group veteran, much less one who's an O-5 rank and who gets paid to write for a living.

Sunday, April 20, 2014

On Combat Shooting (Part II)

Anthony G. Williams, in his article Assault Rifles And Their Ammunition: History and Prospects cites this line from Dual Path Strategy Series: Part III - Soldier Battlefield Effectiveness written by the PEO Soldier G5, Strategic Communications Office in August of 2011, to support his idea for a 6.5mm general purpose cartridge (GPC):
"Ultimately, Army service rifles must be general purpose in nature and embody a series of tradeoffs that balance optimum performance for a wide range of possible missions in a range of operating environments. With global missions taking Soldiers from islands to mountains and jungles to deserts, the Army can’t buy 1.1 million new service rifles every time it’s called upon to operate in a different environment."
However, earlier in that paper is contained this section on the range of the rifleman:
The maximum effective range of a weapon system is also a key element as it represents the potential for how far out a Soldier can effectively engage the enemy. This is also critical as it affects a Soldier’s ability to leverage an overmatch advantage. Doctrinally, this means that a Soldier will look to engage the enemy at a range that is greater than the range at which they can be engaged by enemy fire (typically 20 percent). According to FM 3-22.9, Rifle Marksmanship M16/M4 Series, there are three ranges of concern. First, there is the detection range, which must be well beyond the effective range of the weapon system. This provides the Soldier time to prepare to engage the enemy at the farthest possible ranges. The next band is the range overmatch distance, whereby friendly Soldiers can engage the enemy, but the enemy cannot engage the Soldiers. The final band is the threat engagement range where enemy personnel can target friendly forces.

Optimally, friendly forces will engage as the enemy enters the range overmatch area. This advantage is short lived however, since a quickly approaching enemy can move through this area in seconds. For example, according to The Encyclopedia of Land Warfare in the 20th Century, the effective range for AK-47 fired on semi automatic is 400 meters. The effective range for an M4 Carbine is 500 meters. The 100 meter difference provides a decisive range overmatch capability so long as Soldiers are proficient at hitting targets at the 400-500 meter range, which is why extensive marksmanship training is so critical.

The range of a weapon system relies heavily on the ammunition the weapon fires and the length of the barrel. Systems that utilize 5.56mm ammunition typically cite ranges of 500 – 550 meters for point targets while U.S. weapon systems that fire 7.62x51mm typically cite ranges closer to 800 meters for point targets. The rounds actually travel further but tend to destabilize after they slow to subsonic speeds and therefore lose accuracy. Longer barrels allow more of the propellant's energy to be transferred to the projectile, resulting in greater range. The spiral grooves inside a rifled barrel impart spin to the round. The spin stabilizes the round which provides accuracy, though it doesn’t necessarily increase the average range of the system.

Regardless of the range potential for certain weapon platforms, the human factor must be considered. Studies have shown that Soldiers can only consistently hit a human-size target more than 300 meters away 50 percent of the time or less on a qualification range. The numbers are significantly lower when a Soldier is operating in high stress environments. 
Therefore, whether a Soldier is firing a 5.56mm system with an effective range of 500 meters, or a 7.62mm platform with an effective range of 800 meters, what really matters is whether he or she has the skill to hit the target to begin with. Taking the human factor into account, one could argue that the “real world” effective range of a 5.56 system is similar to a 7.62mm weapon platform because the range potential of both platforms significantly exceeds the average Soldier’s marksmanship ability. This is not to say that exceptional Soldiers such as U.S. Army Snipers and Squad Designated Marksmen with specialized training are not fully capable of firing small arms to their maximum potential.

The value of having a system capable of increased range not only depends upon the skill of the operator, but it also depends upon the operating environment. In urban or restrictive terrain, for example, most line-of-sight ranges are significantly less than a weapon’s range potential. In more open terrain, the engagement range increase. For example, according to Lt. Col. Henthorn, in operating environments like Iraq, 80 percent of engagements are less than 200 meters. While in more distributed environments like Afghanistan, only 50 percent of engagements are less than 300 meters. 

What this is essentially saying is that the well-trained rifleman is effective out to 500 meters regardless of the caliber of rifle he is using, even though, in Afghanistan, approximately half of engagements occur beyond 300 meters. Given this, how would issuing GPC-caliber infantry rifles help the rifleman to be more effective?

The paper goes on to talk more about the general purpose round as they define it. Contrary to what Wr. Williams's citation implies, the author of the paper considers the M855A1 EPR to be a true general purpose cartridge, as it can engage a wide variety of targets reliably within the effective range of the rifle. This indicates that what Mr. Williams and the author of the paper (and, indeed, the US Army) mean by "general purpose" ammunition is different.

Regardless, I recommend that the reader follow the link and read the whole thing.

Wednesday, April 2, 2014

Momentum Has Nothing to Do With Stopping Power

There is a major misconception that pops up often in discussions of small arms: That momentum reflects in some way the terminal effect that a projectile has on a human target. It seems to be standard in the gun journalism industry when evaluating new calibers for game or war to test them against steel poppers, implying or even outright stating that this informs the terminal effect of the round. Even Larry Vickers, to whom I am not even close in terms of experience, says in this video about PDWs that the low momentum produced by the 4.6x30 round - making it unable to knock down the steel target - is a "clue" to low terminal performance.

Now, I have little expectation that a 4.6x30 round, which produces about 540J from the MP7, will perform much better against a human target or gel block than a 9mm JHP or even FMJ. It may more consistently perform after penetrating ribs, but in general, the round is limited in its effectiveness by its low muzzle energy, and its ability to deposit that energy in the target (link starts a download). However, is what Larry says true? Is low momentum a "clue" that a round might not have very good terminal effectiveness? Well, I don't really think so. Sure, a cartridge with marginal terminal effectiveness, like the 4.6x30, might have low linear momentum. However, a cartridge like .45 ACP, which in hardball form produces no greater energy than the 4.6x30, produces more than two and a half times the linear momentum; comparable to the much, much more effective 5.56mm round, in fact.

Because of all the variables involved in the problem of terminal effectiveness against human targets - including the target's mental state, the perceptions of the shooter, and most important, the location of the hit - it can be difficult to say what is and is not relevant to the total sum of terminal effect. However, momentum is one metric that can be discounted entirely. Consider that when a gun fires, it creates a force going in two directions, the bullet and gas going forward, and the firearm itself going backward. This force acts on both bodies over the same length of time - that is, however long (and a little after, due to muzzle thrust) the bullet is in the barrel. Because the forces pushing the bullet and gas out the barrel, and pushing the gun backwards against the shooter's shoulder are equal and act over the same length of time, the momentum of the sum of the bullet and the gas propelling it, and the rifle recoiling, is the same. This means that the momentum of the rifle recoiling into your shoulder as you fire will always be greater than the momentum of the bullet as it hits the target, for two reasons. First, because the gases escaping from the muzzle account for momentum lost, and because the bullet loses velocity - and thus momentum - as it flies downrange, whereas the rifle doesn't have to travel to recoil into your shoulder.

However, we observe as the unspoken first law of shooting that guns have a deadly end, and a non-deadly end. If momentum informed the terminal effect of a weapon against living targets, we'd all be dead fools.

So remember, the next time you're shooting silhouette targets with your .45 ACP 1911 and they fall with a satisfying "clunk" to the ground, the only game the momentum of that 230gr hardball ever felled were made of AR500 steel.

Check me out at The Firearm Blog!

About a month and a half ago, I was contacted by Steve of The Firearm Blog to re-post my article The Case Against A General Purpose Cartridge up at his website. After a short conversation, he decided to hire me on as a monthly writer. So far, I've written two articles for them, so my readers should go check them out!

Friday, March 14, 2014

The General Purpose Cartridge Revisited

I've come under some fire on Internet forums for "misrepresenting" the GPC concept as being heavier than it would in actuality. While I feel that the concept in my The Case Against article - though constrained by several requirements set forth by some members on Mr. Williams' forum - is a perfectly valid approximation, today I hope to address this complaint by creating the absolute lightest GPC estimate I possibly can while still sticking to conventional ammunition design and fulfilling the basic requirement that it not have any less residual energy at 1,000 m than M80 Ball.

First, I need to recall that M80 produces just over 410 J at that range (.195 G7 BC, 2,750 ft/s muzzle velocity, Army Metro atmospheric conditions). You can see this for yourself if you head over to JBM's ballistic calculator and plug in the appropriate values. My GPC must meet or exceed this value. To really get the lightest weight possible, I'm going to need a very good form factor for my bullet- since this is all about retained energy at range. The best form factor I know of for a service projectile is .889 i7, and belongs (paradoxically) to the first spitzer rifle bullet to see service, the French Balle D, an all-brass 12.8 gram boattail projectile with a fairly unique design. If I scale that bullet down to .264" caliber, it weighs just under 7.2 grams.

Since the Army has spent a bunch of time, money, and effort refining their M855A1 EPR design, it seems unlikely that any new caliber would have a substantially different projectile design. Fortunately, I only need to make moderate changes to the Balle D to accommodate this. The scaled-down projectile will be slightly longer - proportionally - than the original at 33.5mm in length, as well as slightly lighter at 7.0 grams. Now, I can find my ballistic coefficient, which works out to a very impressive .249 G7. Running that through JBM a few times tells me I need a muzzle velocity of 2,800 ft/s to meet M80's energy  at a kilometer:


These are some very impressive ballistics! Now, let's see how much this performer would weigh. To shave as much weight as possible from the design, I am going to use M855A1's peak pressure of 62,000 PSI, as well as the same case taper and shoulder angle of 5.56. Many have argued that 62,000 PSI is too much pressure for a rifle cartridge, and that 5.56's case taper and shoulder angle are a detriment to its reliability in automatic weapons, which is part of the reason why my last estimate was so heavy. This time around, I'm pulling out all the stops; no expense will be spared making this GPC as light as I can. In my opinion, the .5 degrees case taper and 23 degree shoulder of the 5.56mm are adequate, and the 62,000 PSI peak pressure is made safe by more thermally stable propellants. I will move on.

After doing several run throughs with the Powley computer, I found that about 41 grains case capacity was needed to generate the sort of performance I was looking for from 20" barrels (this, as far as I know, being the length of barrel chosen by Mr. Williams as optimum for his GPC). Using Solidworks, I created a fairly svelte case: based on the .30 Remington case head and only 46.4mm long, it has almost exactly 41 grains case capacity:


Here are the Powley results for my completed cartridge:


Judging by the propellant weights of both the 6.8 SPC and the 6.5 Grendel, though, that 29.1 grain charge weight seems a little light to me. A spit-in-the-wind estimate puts me at 34.7 grains charge, which sounds more reasonable. Now, we can figure out how much the cartridge weighs.

The bullet, of course, will be 7.00 grams. Large rifle primers weigh about .35 grams, as I mentioned in The Case Against. The charge, in metric, works out to 2.25 grams, and the case itself weighs 7.39 grams if made of brass, or 6.91 grams if made of steel. I will assume steel-cased ammunition, which gives me a total weight of 16.51 grams per cartridge (16.99 grams for brass). 16.5 grams is absolutely fantastic, and lighter even than Mr. Williams' target weight for a GPC with a 7 gram bullet. Let's look at what that means for the infantry platoon:

Weight of ammunition (only, not including magazines or links) of infantry squad breakdown by squad role: 
Squad Leader: 210 rounds 5.56mm, totaling 2.54 kg
Team Leader: 210 rounds 5.56mm in magazines, 200 rounds linked 5.56mm for M249 totalling 4.96 kg (x2)
Automatic Rifleman: 800 rounds linked 5.56mm, totaling 9.68 kg (x2)
Grenadier: 210 rounds 5.56mm in magazines, 200 rounds linked 5.56mm for M249 totaling 4.96 kg (x2)
Rifleman: 210 rounds 5.56mm in magazines, 200 rounds linked 5.56mm for M249 totaling 4.96 kg (x2) 
Weight of ammunition of infantry squad: 51.7 kg (x3) 
Weight of ammunition of infantry squad with 16.5 gram GPC: 70.5 (x3) 
Weight of ammunition of infantry squad with 20 gram GPC: 85.4 kg (x3) 
Weight of ammunition of infantry squad with M240s in place of M249s: 85.5 kg (x3)

Weight of ammunition (only, not including magazines or links) of weapons squad breakdown by squad role: 
Squad Leader: 210 rounds 5.56mm, totaling 2.54kg
Machine Gunner: 300 rounds linked 7.62mm, totaling 7.26 kg (x2)
Assistant Gunners: 210 rounds 5.56mm in magazines, 400 rounds linked 7.62mm for M240 totaling 12.22 kg (x2)
Ammunition Bearer: 210 rounds 5.56mm in magazines, 300 rounds linked 7.62mm for M240, 140 rounds 7.62mm in magazines totaling 13.2 kg (x2) 
Weight of ammunition of weapons squad: 64.5 kg  
Weight of ammunition of weapons squad with 16.5 gram GPC: 53.0 kg
Weight of ammunition of weapons squad with 20 gram GPC: 63.8 kg

Weight of ammunition (only, not including magazines or links) of platoon headquarters breakdown by squad role 
Platoon Leader: 210 rounds 5.56mm, totaling 2.54 kg
Platoon Sergeant: 210 rounds 5.56mm, totaling 2.54 kg
Radio Operator: 210 rounds 5.56mm, totaling 2.54 kg
Combat Medic: 210 rounds 5.56mm, totaling 2.54 kg 
Weight of ammunition of platoon headquarters: 10.2 kg  
Weight of ammunition of platoon headquarters with 16.5 gram GPC: 13.4 kg
Weight of ammunition of platoon headquarters with 20 gram GPC: 16.8 kg 
  
Total weight of ammunition in the platoon: 229.3 kg    
Total weight of ammunition in the platoon with 16.5 gram GPC: 277.9 kg
Total weight of ammunition in the platoon with 20 gram GPC: 336.8 kg 
Total weight of ammunition in the platoon with M240s in place of M249s: 330.9 kg 
Weight increase in the platoon if Carl Gustafs are issued in place of 60mm mortars: 47.5 kg

As my readers can see, even this extremely optimistic estimate still adds almost fifty kilograms of ammunition to the infantry platoon (to say nothing of the increase in weight from the heavier belt links, magazines, and weapons that would be needed to chamber the cartridge). I've heard some GPC proponents claim that the savings in weight of a GPC vs. 7.62mm would balance out its increased weight vs. 5.56mm weapons at the platoon level; this is clearly not true. The GPC - even the lightest possible GPC - represents a significant weight increase for the infantry rifle platoon (or a corresponding reduction in rounds carried). Further, even replacing the platoon's 60mm mortars with direct-fire recoilless rifles is lighter than switching whole hog to the GPC. The Army has already decided to introduce Carl Gustafs to the infantry, which in my mind neatly solves the issue of having to call in air or artillery support when under fire from long-range Taliban ambushes; this being the primary rationale for the GPC in the first place. If the mortars are left home, American soldiers will be able to project high explosive firepower at long ranges without the need for an expensive and time consuming ammunition change-over, and with no more additional burden at the platoon level than would result from fielding a GPC.

This cartridge I've designed is an impressive ballistic hot rod. It would make some sense for 7.62mm weapons to be replaced with weapons in a similar caliber, retaining the capability of that round while slashing the weight of ammunition by about 30%. I felt much the same in my initial article about my 20 gram GPC estimate. Anything that reduces the soldier's load without reducing capability or introducing problems is probably worth doing, if you can afford it. What I disagree with is the idea that a cartridge such as this should be a general purpose cartridge; that it should be issued to riflemen as well as designated marksmen, machine gunners, and as ammunition for static machine guns. The additional weight of ammunition and rifles, and increased recoil and size, sours the idea considerably in my mind vs. the two caliber system.

Thursday, March 13, 2014

Called It!

I don't normally reblog without commentary, but it seems my earlier notion that the Carl Gustav could be issued in the general Army as a way to improve infantry effectiveness at long range has proven prescient.

Monday, March 10, 2014

.300 AAC Blackout: The End of 5.56?

This PDF from Advanced Armament Corp extolling the virtues of the .300 AAC Blackout vs. 5.56mm includes a curious section:

Boy those sure are some impressive numbers for an overgrown .30 Carbine! Do they reflect reality, though? Let's check JBM's ballistic calculator. First, we'll need to find a ballistic coefficient figure that reflects a 125gr .300 Blackout load. Here's a very impressive looking Sierra 125gr Matchking, but it's BC is in G1, not G7 like we want. Fortunately for us, JBM has a drag function converter. Using this, we get a G7 ballistic coefficient at 2,220 ft/s of .170. Now we can plug all this into JBM's trajectory calculator to see if AAC's claims are accurate. For this, we'll leave energy in ft-lbs, but change range to be in meters:


That's... Pretty much right on the money for AAC's claims. What about their numbers for 5.56mm?


Not even close, for trajectory.

Reevaluating this, if we take 5.56's performance at 500m as a baseline for "maximum effective range", then it out-ranges .300 AAC Blackout by about 110m. Further, it's worth noting that at 250m, 5.56 has less than a quarter of the drop, thanks to its laser-like trajectory, which enables the 25 yard combat zero. Worse, 5.56 actually generates slightly more energy per pound than the 125gr .300 AAC Blackout, with 23.8 ft-lbs/gram, vs. 22.7 ft-lbs/gram (how about those units? Working in firearms sure is fun!). It's also worth remembering that larger FMJs tumble less readily than smaller ones and will deposit less of their energy into a human target, something I can't seem to repeat often enough.

So does all this make the .300 AAC Blackout a bad cartridge? No, I don't think so. It seems like an interesting concept, being able to switch from a quiet subsonic cartridge to a harder-hitting and longer-ranged supersonic one without changing any hardware other than the magazine. Of course, the high speed low drag types in my audience will have to tell me whether that sort of concept is attractive to anyone other than readers of Tactical Life magazine, but it's certainly still worth looking at.

What this does remind us is to trust but verify any data you see in a manufacturer's pamphlet or public materials. In this case, it really does seem like AAC had no problem "massaging" the numbers to make their cartridge look better than it really is.