Optimum Military Rifle Calibur -- Part Deux

This is a little like arguing about how high we should make the mountains or how wide a river should be. No matter what "we" say or "decide" (assuming "we" could agree on anything) the military will make a choice based on what "they" feel "they" need, based on factors most of "us" don't even consider, like the number of rounds can be loaded on a C5A. And "their" choice might be not at all what "we" think it ought to be.

Jim
 
It's supposed to be our country isn't it? It sure as hell isn't going to be if we don't dictate a few things

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The Alcove

I twist the facts until they tell the truth. -Some intellectual sadist

The Bill of Rights is a document of brilliance, a document of wisdom, and it is the ultimate law, spoken or not, for the very concept of a society that holds liberty above the desire for ever greater power. -Me
 
Badgerarms, while we might come up with one cartridge that speaks to all of those applications you listed, I expect that it would end up being a poor compromise. I'd rather continue with 4 small-arms cartridges, but along the following lines (here Ivanhoe goes again);
- .45 ACP
- 6x49
- 7x64
- .50 BMG
Weapons would include;
- semiauto pistol, .45 ACP (basically a single-column Glock, maybe 30 oz dry weight though)
- subgun, .45 ACP
- standard issue rifle, 6x49 (includes scoped marksman version)
- folding stock carbine, 6x49 (same chassis as std issue rifle)
- SAW-type light MG, 6x49
- sniper rifle, 7x64
- LMG, 7x64
- HMG, .50 BMG
- sniper rifle, .50 BMG
The 6x49 cartridge might include an 80 grain basic FMJ tumbling penetrator and a 100 gr FMJ-BT for marksmen. Same case/rim diameter as 5.56x45, but longer and with more neck and a bigger bullet. The 7x64 cartridge (a .280 Rem with feedability improvements) might have 140gr AP and 175gr FMJ-BT loads.

Note that the performance of the 6x49 would need careful evaluation in the carbine (though I think 16" is the minimum barrel length I'd allow, none of that 11" nonsense). The 7x64 might be shortened, but I'd like to see more velocity and range than the 7.62x51. Support troops would get the subgun, not the pistol. The pistol would primarily be for MPs and spec ops.
 
Ivanhoe... This is a totally different direction but I think it is just as interesting. I don't know what a 6x49 is, so I'll stick with what I know. It might be that the 6x49 is the answer though.

357 Sig -- 125 grain Truncated Cone FMJ at 1350 FPS
250 Savage -- 87-100 grain VLD at 2700-3000 FPS
20MM Air-Burst Grenade.
50 BMG 600 grain VLD at 3000 FPS

Guns:
Compact pistol in the Glock 19 Class.
SMG such as H&K UMP
Carbine as in HK G-36K
Rifle -- HK G-36
LMG -- HK G-36 Heavy Barrel
GPMG -- FN MAG derived, and lightened.
10 Round magazine semi-auto Grenade Launcher.
Sako 75 Sniper Rifle in 250 Savage
50 BMG HMG... Browning M-2 of course.
50 BMG Sniper Rifle (Barret or similar Semi-auto)
155 MM Howitzer launching Tactical Nuclear Warheads.

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God made us in his own image.
Thomas Jefferson made us free.
John Browning made us equal.

Without Browning, we might not know about the other two...

[This message has been edited by badgerarms (edited August 30, 2000).]
 
Ivanhoe,
Why would you issue support troops a subgun instead of the folding stock carbine version of your rifle? Subguns are pretty specialized weapons. Most armies now just use them for special operations forces in specialized roles.

The folding stocked carbine version of your service rifle would be much more suitable. Compact enough not to be too unwieldy for support troops to carry, but powerful enough to let them slug it out with enemy SOF or first echelon troops that penetrated the front lines, or insurgents. All of these threats would most likely be armed with standard Infantry type rifles.

Save your subguns for your special operations types and aviators.

Jeff
 
In this thread, at least, he never said he was gonna issue .45 to infantry....

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The Alcove

I twist the facts until they tell the truth. -Some intellectual sadist

The Bill of Rights is a document of brilliance, a document of wisdom, and it is the ultimate law, spoken or not, for the very concept of a society that holds liberty above the desire for ever greater power. -Me
 
Dangus,
I guess it all depends on how you ID "support" troops. The U.S. Army breaks them down like this: Members of Infantry and Scout Squads are Cat I firers. They have the most stringent training requirements. Other soldiers (even though they may have an Infantry MOS and be assigned to an Infantry unit) are Cat II. They have less stringent training requirements.

Currently almost no "support" troops (other branches that operate on the battlefield; Artillery, Engineer, various Quartermaster and Ordinance types) are issued pistols and haven't been since WWII. The M1 Carbine was developed to give those units some combat punch and self defense capability without making it harder to do their primary job by encumbering them with the long and heavy M1 rifle. Many of these branches operate either at the front (Combat Engineers) or just behind the front (Cannon Field Artillery). They especially need the firepower of a standard weapon cartridge but in a more compact package then the standard service rifle as their primary job is not to engage the enemy with rifle fire.

Airborne, Airmobile, Enemy Special Operations Forces and Insurgents can make the rear areas the front line at any time. In fact POL points and other logistic sites are prime targets for these forces. Soldiers in these units also need to be armed with full power weapons. Sure an MP5 or smaller subgun would be very handy for these soldiers to carry around (they could almost strap it to their LBE and just wear it) they would soon wish they had rifles if they were attacked. Even the with the high volume of fire you can put out with a unit armed with subguns, you are still shooting pistol caliber ammunition and striking the same blow as if you were shooting a pistol. Body armor is becoming standard in most armies nowdays. I think the .45 would have problems defeating even a standard kevlar flak jacket at 100 meters.

Jeff
 
I have often wondered what would have happened if the British or American armies had adopted the ~.280 caliber cartridges that were debated in the early decades of the 20th century. The Swedes, I think, were the only army to adopt a cartridge in this general size, the 6.55x55. It's a pretty interesting compromise between the 8mm/.30 "full size" cartridges and the current 5.56mm cartridges. Maybe the problem turns out to be that it's neither fish nor fowl...
 
<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by JNewell:
I have often wondered what would have happened if the British or American armies had adopted the ~.280 caliber cartridges that were debated in the early decades of the 20th century. The Swedes, I think, were the only army to adopt a cartridge in this general size, the 6.55x55. It's a pretty interesting compromise between the 8mm/.30 "full size" cartridges and the current 5.56mm cartridges. Maybe the problem turns out to be that it's neither fish nor fowl...[/quote]

Make no Mistake, the 6.5x55 is a long and very powerful cartridge. It is longer than the .308 and only slightly less powerful. I do believe that in Full-Auto use, it would be in the same recoil class and muzzle blast is horrendous on short rifles. Others in Part I were leaning towards 140gr bullets, but I'd top it off at 100gr for the sake of having a controlable weapon in rapid or full-auto fire.



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God made us in his own image.
Thomas Jefferson made us free.
John Browning made us equal.

Without Browning, we might not know about the other two...
 
badgerarms, the 6x49 is just my designation for the next-generation light rifle round. Its something I've been noodling over (despite having no expertise in the subject matter). Being more than 50 miles from Quantico, that makes me an expert! ;)

(If you haven't heard this one before, the word "expert" comes from X, meaning unknown, and "spurt", meaning a drip under pressure.)

Basically the idea is to retain rather high muzzle velocities a la the 5.56x45, while allowing either heavier bullets (for improved penetration) or lower pressures (for better reliability). Same case base diameter as the 5.56 so 30 round mags aren't too huge. The dillemma is to go for a relatively untapered case (gives a more vertical stack in the magazine, thus makes mag design/manufacture easier) or go for taper (more reliable feeding perhaps).

Jeff, I can't argue with your logic, but I'm concerned that the Ordnance folks might yield to pressure from the "user community" to dock the barrel too much for a high-velocity rifle round. Theoretically I agree with you, as a 16" AR beats the hell out of any subgun I know of for up-close-n-personal problem solving, but I'd rather have a 12" barreled subgun than a 12" barreled carbine. That's my pessimistic thinking, anyways. Having recently read "Breakout" by Martin Russ, and a couple other memoirs, GIs seem to have loved the Thompson as long as the ranges were limited to 100 yards or so. The body armor issue is a real problem as you indicate.

JNewell, the "neither fish nor fowl" issue I think is the tricky thing with intermediate rifle rounds. That's why I split things into light/fast and heavy/fast, because with FMJ and especially AP ammo, velocity seems to be the critical thing, unless we go back to a heavy/wide/slow cartridge like the .45-70. So, for light rifles, we've got to give up bullet weight to retain the 3000 fps or so that seems to be needed for terminal effectiveness, otherwise the recoil becomes a problem. For MMGs (medium machine guns) at M60 size, as well as semi-auto sniper guns, then we can go to full power rounds because the gun weight is there to reduce recoil effects.
 
I realize it's a logistical nightmare, but we seemed to do pretty well in WW2 with a variety of calibers.

If it was my military (and it isn't) I'd have the infantry trained intensively in the M-14, M-16/M-4, M-249 SAW, M-240G, M-2HB, M-203 40mm, and some others, and when the fit hits the shan, the topkick can configure the unit as he sees fit since they are all cross-trained. (assuming supply is capable of supporting the shift)

FIBUA/MOUT: More M-14s and .308 MGs. Some M-40A1 and/or M-24 rifles to the best marksmen.

Jungle: Mostly .223 (debatable I know)

Scare the crap outta a 3rd world rifle company: 80% GPMG (an SAS patrol did something like this in the Falklands)

Static defense: all the M-2s you can get your hands on

I know I'm dreaming, but ...

Edmund
 
<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Ivanhoe:
Same case base diameter as the 5.56 so 30 round mags aren't too huge. The dillemma is to go for a relatively untapered case (gives a more vertical stack in the magazine, thus makes mag design/manufacture easier) or go for taper (more reliable feeding perhaps).
[/quote]

Tapered cases are more reliable for a few reasons. First, he taper allows for sand and grit to be lodged in the chamber and the round can be mashed whereas straighter cases might wedge grit and require a 'forward assist' to remedy the situation. Also, a slight movement in the case creates a large gap in the chamber wall. I think that the 250 Savage has a good balance of taper and case capacity efficiency. It has much more taper than the .308 and much less than the 7.62x39. It's also got a sharper shoulder providing more positve headspace. My opinion of course.



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God made us in his own image.
Thomas Jefferson made us free.
John Browning made us equal.

Without Browning, we might not know about the other two...
 
badgerarms, there is a downside to taper, however. The greater the taper, the greater the net thrust on the bolt face, since the case won't carry as much friction. Plus, I believe the curved mags that a tapered case requires aren't going to be as reliable as a straight mag. So, its a tradeoff.
 
<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Ivanhoe:
badgerarms, there is a downside to taper, however. The greater the taper, the greater the net thrust on the bolt face, since the case won't carry as much friction. Plus, I believe the curved mags that a tapered case requires aren't going to be as reliable as a straight mag. So, its a tradeoff.
[/quote]

Point well taken. A little taper is necessary, though. I don't think case friction is as much a factor as you might think. On a straight walled case such as the 357 Magnum or 45 Auto, yes. But locked breech rifle it's really a non-issue. A case-in-point

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God made us in his own image.
Thomas Jefferson made us free.
John Browning made us equal.

Without Browning, we might not know about the other two...
 
But locked breech rifle it's really a non-issue. A case-in-point.

I disagree. Especially after you get a monday morning batch of ammo that hammers the locking lugs on the bolt 65 thousandthes into the barrel extension. Bolt thrust is more critical on other types of firearms, I agree. But you can't ignore it for any of them. Especially when making allowances for a combat weapon. And how much pressure are you expecting to need to make this 6mm SAW effective? :) Semper Fi....Ken
 
<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by EchoFiveMike:
I disagree. Especially after you get a monday morning batch of ammo that hammers the locking lugs on the bolt 65 thousandthes into the barrel extension. Bolt thrust is more critical on other types of firearms, I agree. But you can't ignore it for any of them. Especially when making allowances for a combat weapon. And how much pressure are you expecting to need to make this 6mm SAW effective? :) Semper Fi....Ken
[/quote]


For some reason the rest of my post disappeared. I was going on to cite the case of the Lee Enfield rifles which are plenty strong enough as rear-lugged guns to handle the .303. Remember also that I think the 250 Savage is just fine. Working pressure should not exceed 50,000 psi IMHO. I think the net gain in backthrust from the taper differences we are talking about is minute on guns that are proofed at over 100,000 psi without damage. Perhaps the true test of the weapon should be submerging it in water and firing. It should cycle normally. How about dumping sand through the ejection port while firing? I doubt that a two degree change in taper will matter all that much.

As for magazine curvature, who ever called a curved magazine unreliable? Why? Cite unreliable examples.


------------------
God made us in his own image.
Thomas Jefferson made us free.
John Browning made us equal.

Without Browning, we might not know about the other two...
 
Several problems with a curved mag. One is production; its going to be easier to manufacture a rectangular box mag than a curved one. Two, if you go with a mag that curves all the way to the feed lips, you end up with the "hook and rotate" type of latching mechanism (a la the Mini-14) which requires more dexterity than a straight "shove it in the well" mechanism. If the mag has a straight section, then its easier to insert into the well, but then the follower has to negotiate the change in radius in the straight section (requiring a loose follower). Third problem is that it is more difficult to make a mag pouch that is easy to extract mags from.
 
Hi, Dangus,

You said, "It's supposed to be our country isn't it? It sure as hell isn't going to be if we don't dictate a few things."

Assuming "we" had the power, how in heck could "we" dictate to the military when "we" (on this forum) can't even agree on what "we" think. Further some of "us" admit that they know next to nothing about the subject. No one seems to consider small details like production, cost of change, weight and size of ammunition, functioning, lethality, penetration of light armor, etc., etc.

Further, "we" are engaged in very conventional thinking (brass cases and bullets) when DARPA and others are way beyond that stuff. We are almost into the X generation of military weapons; they are working on Y and Z and who knows what else. Phasers, anyone? Yes, I am serious; something very like that is in the mill, the current (pun intended) problem is an energy source.

Jim
 
<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Ivanhoe:
Several problems with a curved mag..... Snip .....[/quote]

Agreed on all counts Ivanhoe. My question was about reliability. Curved magazines aren't any more or less reliable IMHO. I like the rock-to-lock magazines myself. Plastic magazines are the same cost to manufacture curved or straight. Finally, mag pouches are just a little bit larger for curved magazines. I'm not talking about AK-47 curve here either.
 
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