The Ultimate Combat Round

[Nolo]

Thanks, Monkeybear.
Yes, I know I'm jumping the gun. I always have. I look back at designs I did literally weeks ago and I know they they won't work, or they won't work as I want them to. I can't really help it. I try and redesign everything. I'm not sure where you got my first quote from, but I think it was from much earlier in the thread, and probably from an obsolete design. Oh well. It still applies, and you are still right.

Yes, I can gloss over complex problems, but I come back to them eventually. Sure, if I decided with the thread to go the caseless route (which I didn't), I would redesign the G11, internals and all. I looked at the insides and the basic operation and I said "there's got to be a better way to do that". Whether there is or not, I don't know, and, if I cared about it right now, I'd be spending most of my time trying to figure out that better way.

How does telescoping work? The pin strikes the primer. The primer lights a fast burning powder that pushes the bullet and some of the powder down the barrel far enough so that pressures will be acceptable. Then the rest of the powder ignites pushing the bullet out of the barrel at high speed. The Army is actually looking at a telescoping MG design right now.

 

[Tony Williams]

Nolo said: How does telescoping work? The pin strikes the primer. The primer lights a fast burning powder that pushes the bullet and some of the powder down the barrel far enough so that pressures will be acceptable. Then the rest of the powder ignites pushing the bullet out of the barrel at high speed. The Army is actually looking at a telescoping MG design right now.

Correct, but that isn't going to change the relationship between pressure and velocity by comparison with conventional ammunition. All it does is enable telescoped ammunition to be made more compact than conventional ammo of the same performance.

 

[Nolo]

Sure it doesn't. The reason that you don't need as much powder in the Knox rounds is because they use a more efficient (i.e. produces more gas per gram of powder), slower burning powder. I see nothing particularly special about smokeless powder, and I see no reason why someone couldn't improve on it, and, apparently, someone did.

 

[jkingrph]

Why reinvent, Look at the 6.5 Swede.

 

[Nolo]

Why reinvent? Because I can. Anyway, the rounds that I've come up with are far superior to the Swede, as well as most other rounds currently being fielded.
That is, of course, provided that they work.

 

[Tony Williams]

Sure it doesn't.

I'm not sure whether you're agreeing with me or not

The reason that you don't need as much powder in the Knox rounds is because they use a more efficient (i.e. produces more gas per gram of powder), slower burning powder. I see nothing particularly special about smokeless powder, and I see no reason why someone couldn't improve on it, and, apparently, someone did.

Certainly better powder can be invented. But the point I was making is that to achieve a given velocity with a given bullet, you need the same total "push" behind the bullet to get it up to that velocity. And that "push" is pressure. This is basic physics: the pressure curve can be altered, but the total "push" has to be the same.

If powder is tightly compressed, the pressure goes up. Conventional ammo has plenty of air spaces between the grains (even if the case is full), which gives some expansion room. Ammo for telescoped rounds is often finer grained and packed more tightly, so it uses a lot less space. This would normally cause an unacceptable increase in pressure, but the fact that the bullet is kicked up into the barrel by a smaller charge first provides that expansion room to keep the pressure in check.

 

[Nolo]

I'm agreeing with you.
What you said is absolutely true, the only difference with the Knox rounds is that their powders are more efficient, that's all. So, not only are they saving space by telescoping, they're saving space by having a more efficient powder.

 

[Jason_G]

This might sound a little odd, but honestly I can't see why a steel core version of the 6mm Remington wouldn't be a good choice. It's flatter shooting than the 5.56 NATO, with ballistics very similar to the 6.8 SPC. It also has the same mass as the SPC, but would be a little better in terms of penetration due to the smaller diameter. Put a steel AP core in it and you would have a good combat round with little recoil, light weight, and more umph than the 5.56.

Jason

 

[Nolo]

It's the weight, Jason. I'm guessing the 6mm Remington pushes a 100-grain-ish bullet down at 3000-ish f/s. That'll give you about 2000 ft-lbs, and, in a package the size of 6mm Remington, I'm estimating about 50000 EPP, which is no better than 5.56. Sure, it's performance is better than 5.56, so it's technically a better choice, but we can do better. See my 6mm carts.

 

[Jason_G]

It's the weight, Jason. I'm guessing the 6mm Remington pushes a 100-grain-ish bullet down at 3000-ish f/s. That'll give you about 2000 ft-lbs, and, in a package the size of 6mm Remington, I'm estimating about 50000 EPP, which is no better than 5.56. Sure, it's performance is better than 5.56, so it's technically a better choice, but we can do better. See my 6mm carts.

It ain't that heavy. Not a whole lot more than the 5.56 really. Anyway, I think at best EPP and EPM are fairly useless stats. At worst they are downright misleading. I think individual round performance (short range, long range, and terminal ballistics) vs. overall weight are what would be wisest to look at, especially for the rifleman's role. A soldier in the field isn't going to give a rat's ___ as to how much potential energy is stored in his mags. He's just wanting the bullet to go where it's supposed to go and kill what it's supposed to kill, none of which are ultimately dependent on the amount of energy present, although it doesn't hurt. If each bullet can do its job effectively, you don't need as many rounds, and EPM and EPP just don't matter. Also, the 6mm could be loaded hotter than civilian factory loadings, which currently push it at about 3100 fps, and the longer caseneck could accept a wider variety of bullets. There may be better choices out there, but I think it would definitely be a huge step up from the 5.56 NATO. Just MHO.

Jason

 

[GunTech]

Anteater1717,

7.62x45 is a case I had forgotten about, but it might be a good base. I necked the Czech round down to 6.7, and it falls nicely between 6.6 grendel and my 6.5x45mm based on a lengthed 6.5 PPC case. Assuming brass is available, here;s what the round looks like.

Cartridge          : 6.5 x 45 Czech
Bullet             : .264, 108, Lapua Scenar GB464
Cartridge O.A.L. L6: 2.362 inch or 60.00 mm
Barrel Length      : 20.0 inch or 508.0 mm
Powder             : Winchester 748

Predicted data by increasing and decreasing the given charge,
incremented in steps of 0.735% of nominal charge.
CAUTION: Figures exceed maximum and minimum recommended loads !

Step    Fill. Charge   Vel.  Energy   Pmax   Pmuz  Prop.Burnt B_Time
 %       %    Grains   fps   ft.lbs    psi    psi      %        ms

-07.4   87    28.72   2442    1430   40631   7437     95.9    1.185
-06.6   88    28.95   2461    1452   41603   7492     96.2    1.172
-05.9   88    29.18   2480    1475   42600   7546     96.5    1.160
-05.1   89    29.40   2499    1497   43621   7599     96.8    1.147
-04.4   90    29.63   2517    1520   44669   7650     97.1    1.135
-03.7   90    29.86   2536    1543   45743   7699     97.3    1.124
-02.9   91    30.09   2555    1565   46845   7747     97.6    1.112
-02.2   92    30.32   2574    1589   47976   7793     97.8    1.100
-01.5   92    30.54   2593    1612   49136   7837     98.1    1.089
-00.7   93    30.77   2611    1635   50310   7880     98.3    1.078
+00.0   94    31.00   2630    1659   51547   7921     98.5    1.066
+00.7   94    31.23   2649    1682   52801   7961     98.7    1.055
+01.5   95    31.46   2667    1706   54087   7999     98.8    1.045  ! Near Maximum !
+02.2   96    31.68   2686    1730   55408   8035     99.0    1.034  ! Near Maximum !
+02.9   97    31.91   2704    1754   56765   8069     99.2    1.023  ! Near Maximum !
+03.7   97    32.14   2723    1778   58156   8101     99.3    1.013  ! Near Maximum !

 

[Nolo]

It ain't that heavy. Not a whole lot more than the 5.56 really. Anyway, I think at best EPP and EPM are fairly useless stats. At worst they are downright misleading. I think individual round performance (short range, long range, and terminal ballistics) vs. overall weight are what would be wisest to look at, especially for the rifleman's role. A soldier in the field isn't going to give a rat's ___ as to how much potential energy is stored in his mags. He's just wanting the bullet to go where it's supposed to go and kill what it's supposed to kill, none of which are ultimately dependent on the amount of energy present, although it doesn't hurt. If each bullet can do its job effectively, you don't need as many rounds, and EPM and EPP just don't matter. Also, the 6mm could be loaded hotter than civilian factory loadings, which currently push it at about 3100 fps, and the longer caseneck could accept a wider variety of bullets. There may be better choices out there, but I think it would definitely be a huge step up from the 5.56 NATO. Just MHO.

They really aren't useless. EPP and TME are useful because they tell you, in simple ratings, how much basic stopping power (One of the things that is important to the urban infantryman) is in every pound (the other thing he's worried about, i.e. weight) of ordinance he is carrying. It's efficiency. If you could do exactly the same thing that 6mm Remington does in a package that's half as heavy, would you? Absolutely. Is 6mm Remington better than 5.56? In my opinion, yes. Is it the best we can do? I think not. Now, is foot-pounds energy the end-all and be-all of stopping power? No, but if you do things (in otherwords, bullet design) right, then you can effectively make it a marker for stopping power. The most energy-efficient bullet out there is a hollowpoint. Now, the U.S. military can't use hollowpoints (would that they could!), so we have to find another way, or disguise them very well. That's what I plan to do with all of my bullets, and so I can use EPP as and effective short-range rating. You are correct that the EPP rating disintegrates at long ranges. That's okay, because I plan to make up for that with high velocities (which help the EPP anyway, because you are using the light powder instead of the heavy bullet to create energy) and really awesome BCs.

An update on what rounds I am currently attached to (all of them use Knox powder):

I call this round the 5.56x39mm Firebrand Epsilon (as it is the 5th [E] in the series of 5.56mm designs). It pushes a 90-grain bullet at 3550 f/s, and is within the 5.56 NATO OAL. It also has recoil slightly higher than the 7.62x39mm and produces 2500 ft-lbs energy. Would make a great overall standard round, as it is quite capable as a DMR cartridge, an MG cartridge, a SAW cartridge and an assault rifle/carbine cartridge.

Not sure if I've put this one up before, it's the 6mm Firebrand Gamma, a 110-grainer doing 2,900 f/s for 2000 ft-lbs.

This is the 5.56x28mm Firebrand Delta. It does 3,000 f/s with a 90-grain bullet. It also has the advantage of being able to use a through-the-grip magazine.

 

[GunTech]

Telecoping rounds are nothing new. In modern ammunition they date back to at least the 1940s and the Hughes Chicklet. They are a change in form factor, nothing more.

I am extremely suspicious of any claims of more efficient powders. Generating more gas from a small amount of propellant buys you exactly nothing. It is the volume of the gas in the case. If you have a powder that reuires less volume and put it in a smaller case, pressure shoots up.

The only way to increase velocity without increasing peak pressure is to extend the working pressure over a longer period of time. This has proved to be extremely hard to do with propellants alone. It can easilt done by electrotherm (ET) and electromtheral chemical (ETC) protellants, but this has not proved practical in small arms.

Basically, you can compromise. You still have to deal with pressure, velocity, size and recoil no matter what. There is no magical solution that will give you the perfect round.

 

[Nolo]

Even if the Knox powders aren't truthful, I'm sure one can do it somehow.
Maybe even me.
I see no reason why you couldn't use the telescoping ammunition to reduce the pressure of the round. You use a small, efficient powder charge and then telescope it to reduce the pressure.

 

[GunTech]

Unfortunately, it doesn't work that way. The bullet doesn't start to move until the pressure is fairly high, and the pressure wave moves faster than the bullet can (propellant gas expands at at leat 4000 fps, any can be as high as 6,000 fps). You might be able to do something with a sabot which had a low coefficient of friction and a fairly large area, however this concept has been around since before WWII and hasn't met with any success to date. If you look at the time/pressure curve of typical propellants, it easy to see why. Most of the propellant burns before the bullet has even left the cartridge.

 

[Nolo]

It's not that you are incorrect, it's just that I don't see why. I get that you need pressure to push something fast. That's a "duh" for me. But by what you said as I understand it, you could never push something past a certain speed, no matter what powder and case capacity you had. I know it is impractical to push a bullet faster than about 5,500 f/s, but that's not the speed I'm looking for.

 

[Rifleman 173]

Having been in combat, one thing that most ammo designers FAIL to understand is that American soliders and marines will, sooner or later, be going up against enemy forces who use narcotics/drugs to DELIBERATELY offset the effects of our shots. In Nam we sometimes faced communist troops that were stoned to the gills with opium or heroin in them. In Mogodishu (Black Hawk down) it was suspected that the troops that attacked the Americans there used very strong hashish possibly laced with something like opium. Your minimum bullet weight should be 120 grains and more would be better. Your minimum bullet diameter should be 7.62/.30 caliber. The length of the bullet should be more like a spear (long, heavy & thin) than a dart (short & light). The bullet should have good velocity to give it punch and accuracy. You do not need to have a 30 round magazine. If you design your ammo right, you can use 25 round magazines instead. Your firearm should be "modular" in design sort of like a FN/FAL, Steyr AUG or good AR-15/M-4. My suggestion would be to have each weapon come with a system of changeable uppers so that the user could switch upper halves from rifle to carbine to light machinegun (heavy barrel) depending upon desired use OR design it to be like a light machinegun with a selector switch to allow the shooter to also use it as a rifle. Sort of like the combination machinegun/rifle that the old German paratroopers had in WW2. They loved their firearm. Also do NOT try to re-design the AK-47 (7.62 X 39) cartridge. Come up with something new that uses new technology and new chemistry. If you meet all of these suggested ideas, you WILL make a large number of people happy.

 

[rangerruck]

Basically , the round you have in mind allready has been round long time. 5.6 x52. Also known as the savage hipower. shoots an 80 grain bullet at 3400 fps from a 24 inch bbl. slender cartridge, light, can carry a bunch , can belt feed no problems, nice long necks. If we dont' wanna do this, the the old 6mm remmy would do all the above, even easier, with 95 grain fmjs or power points. superlong necks for better bbl life, easier on the wear and tear, smoothly tapered cartridge. 600 yard shots, and knock over a deer like it has been struck by lightning.

 

[Nolo]

Having been in combat, one thing that most ammo designers FAIL to understand is that American soliders and marines will, sooner or later, be going up against enemy forces who use narcotics/drugs to DELIBERATELY offset the effects of our shots.

You're absolutely right. Which is exactly why I'm trying to design a round that incapacitates the enemy as quickly as possible. The real way to do that is by opening up as many arteries and veins as possible in the target. I think fragmentation is the key here.

Your minimum bullet weight should be 120 grains and more would be better. Your minimum bullet diameter should be 7.62/.30 caliber. The length of the bullet should be more like a spear (long, heavy & thin) than a dart (short & light).

I hate to say it, but a 120-grain .30-caliber bullet is not going to be shaped like spear. It will be shaped like dart (short & light). Heavy and thin would be a 120-grain 6.5mm, a 105-grain 5.56mm or a 90-grain 4.7mm. I don't want to go all the way down to 4.7mm, so I'm going with a 90-grain 5.56mm round. Much heavier than our current round, the same standard caliber and the bullet goes as fast.

You do not need to have a 30 round magazine

Technically, you only need a single-shot weapon. But a 30-round mag is nice. I think that mags should be arranged with bullet power according to a logical table, like this:
-500-900 ft-lbs; 50 round mag
-1000-1400 ft-lbs; 40 round mag
-1500-1800 ft-lbs; 30 round mag
-1900-2500 ft-lbs; 20 round mag

Your firearm should be "modular" in design sort of like a FN/FAL, Steyr AUG or good AR-15/M-4

I agree. But this is about the rounds, not the rifle.

Also do NOT try to re-design the AK-47 (7.62 X 39) cartridge. Come up with something new that uses new technology and new chemistry.

Well, if you look at the redesign that I did for the 7.62x39 round, it did precisely what you suggested. When I designed that cartridge, I wasn't thinking about the 7.62x39mm cartridge at all. I actually was trying to apply Knox technology to a round that would push a 180-grain, .30 caliber bullet at 2800-2900 f/s. When I designed it, it was so similar in dimensions to the 7.62x39mm round that I decided to just use that case. You get the performance of a 7.62N in heavy loadings, a good 6mm cartridge (saboted) in lighter loadings, and you have the added benefit of being able to use captured ammo.

Basically , the round you have in mind allready has been round long time. 5.6 x52.

Performance-wise, maybe. But not exactly. See, unless 5.6x52 has an extremely thin (I suspect that it is about 9-10mm, which is far too large) case, which I doubt, then it is much heavier than the cartridges I am looking at. Soldiers care about weight. They care about the amount of ammunition they can carry before they become overburdened. My goal is partially to imporve performance, but it is more about reducing weight.

 

[rangerruck]

http://www.loaddata.com/images/database/ACFA3E.gif
http://accurateshooter.net/Diagrams/223remx330.gif

 

[Nolo]

That's bad for a couple of reasons. The .22 Savage high power appears to be rimmed, not a good fit for automatics. Second, it appears to be quite old (utilizing less advanced technology). Third, it's even larger than I expected it to be (12mm!). Fourth, if I were to fix all these problems and then improve on it, I'd end up with the cartridges I've already shown you.

 

[GunTech]

You don't want to make a conventional FMJ bullet long and thin. It won't tumble and fracture and yuou end up with the lethality of the Italian Carcano. Big bullets aren't necessarily good either. Remember that you are limited to FMJ by treaty. All of the 30 caliber bullets the US has used are very stable and tend to drill right through a target with little upset and distortion. It's owrht noting that in Vietnam, the 5.56x45mm M193 was actually shown to be 11% more lethal at combat ranges than the more powerful 7.62x51mm. The reason is simple - the M193 would tumble and fracture in tissue creating multiple submissiles. The 7.62x51 would pass straight through losing v=little velocity. This has all been covered in this thread previously.

With regard to a new cartridge, it is worth noting that there has been very little improvement in propellant technology in the last 100 years, so assuming there will be a great change is a false hope. What has change thing somewhat is new materials, and cartridges can be loaded to slightly higher pressures.

It is ultimately the total volume og gas produced in deflagration that will determine velocity. More powder produces more gas, but the more gas in a given case, the higher the peak pressure. Thus, you will have a larger case volume for a higher velocity for the same bullet.

Ultimately, there is no magic formula that will get you a super-cartridge. You have to make compromises. You can have a larger, fast projectile from a small cartridge at safe pressure. The 5.56x45 was a concious decision to limit range and power in exchange for more ammunition. If you don't think 5.56 has enough power, you can go up in caliber and you'll end up with a larger cartridge. Period.

Many here are basically arguing that therer exists a middle ground catridge that splits the difference. Rounds like the 6.8 SPC and 6.5 Grendel fall into this category. Are they clearly suoperior? Probably not. They just change the compromises. They may have more general utility than existing rounds, and thus be more approrpiate for more situations than existing rounds. You are never going to have a perfect round for every conceivable military scenario. Whay works very well in dense jungle may not be appropriate for open mountainous terrain. But perhaps there is a decent 'jack of all trades, master of none' round.

My own 6.5x45 was lterally a 'split the difference round'

5.56x45 62gn bullet
7.62x51 150gn bullet
Average 106gn

5.56 = 0.224
7.62 = 0.306
Average = 0.266 = 0.264 =6.5mm

M855 3000fps
M80 2850fps
Target velocity ~2925

So, a 106gn 6.5mm bullet at about 2900. And thus a catridge somewhere in zize between the 7.62x51 and the 5.56x45

Resulting in the 6.5x45

This cartridge, 'on paper', will throw a 107gn SMK at 2900fps with M16 safe pressures, or a 100gn FMJ at over 3000. If long range precision is needed, a 'special ball' analog to the M118LR could be created using a 123 or 139gn Scenar bullet that will compare vert favorably with the best 7.62x51 LR ammunition.

The downside's are that the rifle will have to be slightly larger - basically a M16 with a magazine that is 0.250 inches longer. The ammunition will be larger and heavier, thus fewer rounds could be carried - more than 7.62x51 but fewer than 5.56x45. Recoil would also be heavier than 5.56x45. Just slightly more than a 9 pound AK firing M43 ball.

As noted, it just a 'different' compromise.

 

[GunTech]

Nolo,

Here's my 5.7x45mm, which will toss a 62gn M855 bullet at a calculated 3395fps with normal M16 safe pressure. It will even fit in an existing M16 magazine. Based on the 7.62x45mm Czech with 5.56x45 shoulder (23 degrees) and a slightly more tapered case (30 minutes 30 seconds).

It's only 100 fps slower than a 22-50 and can be fired from an AR-15.

 

[HorseSoldier]

Trying to tailor rounds to stop people on drugs is kind of pointless. It happens occasionally, but is one of those things highly mythologized and exagerrated (especially by those who find real world bullet performance in any caliber to not match their Hollywood fueled expectations, etc.).

And when people are in some altered state of conciousness due to drugs you get a declining benefit trying to make the bullet do the work. Central nervous system hits work regardless of caliber, and anything else is uncertain if drugs (or more commonly adrenalin surge) are letting someone shrug off injuries. The training to put the bullets where it matters and the mindset to recognize that you're going to kill someone and if one bullet doesn't do the job you need to continue attacking, continue shooting, and put someone on the ground dying are worth more than some special junkie-busting bullet.

 

[Slugless]

I admit to not having read this entire thread but skimming for the more interesting bits...

Nolo, have you been looking into terminal effects of bullets? I saw you mention fragmentation to open up vein & arteries, but it's a bit more complex than that.

My understanding - it's common for weapons designers to start with the bullet, then go to the casing, and finally the rifle. The bullet is designed for certain terminal characteristics, such as:

crushing, which produces a permanent cavity
stretching of tissue producing a temporary cavity

That's really it. Since a hollowpoint is out of the question (I'm not sure what you mean by "that's what I plan to do with all of my bullets"), the bullet must be designed to tumble at all effective ranges. The AK74 projectile has a 5mm long air space in the tip to move the CG back towards the tail so it tumbles very effectively, a little sooner than ours. Tumbling should start very early, 10 cm or so. Fragmentation is great but given our experience with the 5.56 rounds fragmentation should not be counted on but it sure is a plus. The Russians could have done that but their round appears to be designed for two tumbles while in flesh. I don't know what the 5.56 does w.r.t. tumbling if it doesn't fragment.

I've not looked at the pretty pics of ballistic gel tests, my reference is Emergency War Surgery, a NATO handbook, 1988 ed. The surgeons know what kills and incapacitates.

I think you'd like this book very interesting. Let us know what the school librarian thinks when you ask for it inter-library loan! "It's for a biology class project, ma'am"

Anyone have a good link to gel tests?

HorseSoldier, I hear you & know what you mean but I recently spoke with a Marine who fought in Fallujah and they were clamoring for a more effective round because their opponents were high. They found some opponents "on the ground dying" who turned into "ghosts" and had to be re-shot. Hence the Kevin Site's video. Pointless to tailor rounds to stop people on drugs? Where did the development of the .45APC come from? It was certainly a perception before.

Food for thought.