The Browning Automatic Rifle was extremely popular amongst American troops during WW2, but was later relieved, first with the M60, and later with the M249 and partially the M240. While a beltfed is good to have, I feel that they are a bit too heavy and complicated to operate, to fully show its potential.

As an old machinegunner myself, I´m used to the MG-3, and have a love/hate relationship with it. Nothing can beat a beltfed in a stationary position, as you won´t have to carry any ammo, the QCB is ready to use, and the weigth of the weapon is working with you, and not against you. Also, you won´t have any failures because of dislocated rounds in the belt, the belts are clean and ready for use...

The BAR could have been a great weapon on the battlefield still today, if it wasn´t for three shortcomings:

-Too small magazine-capacity.

-No QCB

-Heavy weight compared to modern weapons with more firepower.


When it comes to magazine-capacity, the restricting factor was ground-clearance. With a larger capacity magazine, the bottom ogf the mag would touch the ground when firing in the prone position, which is not a good thing.

The German FG42 had a sidemounted magazine, and thereby worked its way around that restricting factor. Unfortiunately this design had its own shortcomings, as it was not easily operated from both sides, and because of the weight of a full mag, the operator needs to counterbalance it to fire accurately.

Another design that was fielded during WW2 was the Bren-gun, easily recognizable by its top-feeding magazine. The Bren was usually fielded with 30rd mags, but a 100rd drum was also available. It also had a QCB. The downsides with the Bren was its heavy weigth, and that an off-set sight was needed. The Bren was however extremely popular amongst the British, and The Bren was even rechambered to accept the 7.62 NATO-round, and was renamed as the L4, and actually saw active duty in the British forces as late as 1991 in GulfWar1.
One detail which did not lessen its popularity was the fact that the mags from the L4 and the L1 (FAL-rifle) actually was interchangeable.

A fact with mag-fed weapons is that they are more tolerant of abuse than beltfeds. This is partially because they are of simpler design, and also because a magazine protects the ammo from pollution. An unprotected belt can introduce the mechanism of a beltfed to all kinds of pollution, from small branches, leaves and grass, to snow, mud and dust. This is will eventually cause the gun to misfire.

To make a long story short, my idea is to reintroduce the automatic rifle to the riflesquad, and let the magazine be interchangeable with the assaultrifles of the squad. The new automatic rifle ("AR") should incorporate designfeatures of the BAR and the Bren:

-Top feed magazine, preferably 40rds or larger capacity. This would make assisted mag-changes extremely quick. Changing magazines should take no more than 2 seconds, and less than 1 second from a well drilled team.

-No QCB, to increase the carrying capacity of the squad. The barrel should be heavy and fluted, to maximze heat-transfer to air. This should enable the AR to fire theoretical bursts of up to 1000rds before failure. In an actual combat situation, the ammo would probably be exhausted before this could happen. Also, 3 or 4 "ARs" should be introduced to each squad, making each fire-team consist of 3-4 soldiers per "AR". This way the actual firepower of the squad would be increased, even though the total weight of the weapons in the squad would remain the same, or even less than with beltfeds. Because every soldier in the squad carries magazines for both the "AR" and the assaultrifle, the other soldiers of each fireteam could act as a co-gunner, emptying his load of "AR"-mags, and the switching positions with another soldier with more mags. This practice could be done on long to medium ranges. On short ranges, increased firepower could be needed, and the soldier handling the "AR" could operate it on his own, while the other soldiers could open up with their assaultrifles. As 40rdmags is usually not used in the assaultrifles, of the same reasons as with the BAR, they would be nice to have in a patrol or  FIBUA-situation, giving machinegun-like firepower to every soldier in the squad.

-The weight of the "AR" should be comparable to that of a 7.62 battlerifle, around 5 to 5.5 kgs. This could be easily done, by modifying a modern assaultrifle design, turning the action upside down, and adding a heavy,fluted barrel. This way, the "AR" could still be used as an assaultrifle, while being a machinegun.

This would altogether probably increase both the mobility and firepower of a riflesquad quite a bit. The situation today is that the soldier struggling the most to keep up with the rest of the squad is probably the machinegunner. That is not a good situation.

However, in stationary positions, the "ARs" should be reinforced with beltfeds, to maximize possible firepower. This way the squad can leave the beltfeds in their vehicle or base when they are not necessary.

Also, being used to 7.62NATO, but having fired a few weapons in 5.56, 5.45 and 7.62x39,it is my opinion that the 5.56 is far too weak for a rifle round, and should be replaced with the 6.5 Grendel, as it would deliver excellent stopping power and penetration in both vehicles and personnel, comparable to 7.62 NATO, in ranges exceeding 1000m. While the 6.8SPC easily outperforms 5.56, It is only comparable to 7.62 NATO in relatively short ranges.

Quoted: -No QCB, to increase the carrying capacity of the squad. The barrel should be heavy and fluted, to maximze heat-transfer to air. This should enable the AR to fire theoretical bursts of up to 1000rds before failure. In an actual combat situation, the ammo would probably be exhausted before this could happen.

Better yet, use a carbon fiber shrouded barrel, which can dissipate heat fast enough to not need a barrel change.

Nice first post.

Hmmm.    Overall I agree with your line of thinking, although I have heard that some do not like the top mount magazine because of dirt entry issues.

Also, I think that many attempts to provide a magzine fed LMG already exist including:

Stoner 63
HK11
Steyr AUG 24"  with 42 round mag and QCB
Brit LSW
Diemaco LMG
RPK series
Robarms M96 Bren config (though it's more of a concept)

also, it's been commented that the Galil and Valmet are nearly squad auto class items in a pinch.

I guess it boils down to cost and what a military is willing to spend to get its troops into combat.  

In the case of special troops who have to be semi-self-sustaining, I imagine that they will continue to procure and use whatever they think is most useful to them.

In the case of regular infantry, I would expect that they will be issued a standard "jack of all trades" weapon.   The M-4 seems to be the dominant weapon of that type at this point.

One thing that I have noticed as a NON-military type who had carried firearms regularly in the field:   They are very heavy, and while heavier cartridges are individually more effective, a 230 grain bullet weights twice as much as a 115 grain and nearly 4X as much as a 62 grain.

Admittedly, the 5.56 does not do great against obstacles, but if I were responsible for walking cross country for 15 miles a day while carrying subsistence items, my weapon and commo gear, I would probably want my primary weapon to weigh about 6 pounds or 2.7 Kg.  

That is goddamn light.  

To provide further indication of the limitations of weight, look at all the crap that US infantry are carrying in Iraq and Afghanistan and they are pretty much entirely vehicle supported.  Between the designators, GPS, optics, ammo, armor, it looks really really shitty for weight.  

How can they operate effectively up stairs and through narrow spaces?  What if they become isolated from their transport and have to negotiate sustained adverse grades with their 80lb external loads?  

Anyway,  I totally agree with what you are saying about needing striking power, but it seems like weight of ammunition is going to be a killer.

Dirt-entry issues? I have never heard of any. Actually a lot of soldiers in the British forces would love to have the L4 back in active duty, because it was very reliable in both arctic and desert conditions, and very compact and handy compared to the Minimi and the GPMG.

The problem with a orthodox mag-fed LMG is first of all that it has (usually) a low magazine capacity, and that mag-changes are time-consuming and relatively difficult in the prone position. Especially is this the case with bull-pups, such as the L86 and the AUG.
Also, the weapons mentioned above, all have in common a relatively high rate of fire, and an ineffective calibre.

By modifying an already existing design,the cost of development and production will be kept down to a minimum. I would guesstimate the price of one "AR" equivalent to less than two standard assaultrifles. Now, how many assaultrifles can you get for the price of one M249? And how many M249 is it practical to carry for a unit, without reducing the ammo-load considerably? Another positive feature of such a design is that it will eject downwards to the left, enabling the co-gunner to assist from the right side, staying out of the gunners field of wiew.

I have carried the G3 rifle in peacekeeping operations in the Balkans, and during my military service . The G3 is a fairly heavy rifle, and it fires 7.62 NATO ammo. The weight of the rifle itself was a much larger problem than the weight of the ammo. I personally carried a load of 180rds of magazined 7.62rds while on patrols. During live-fire exercizes, you could add 600rds of 7.62 + an QCB on top of that, or eventually a 12.7kg MG3 +200 rds of 7.62. Then things start to get heavy. Belts, or pouches with belts in is generally more cumbersome to carry than magazines, especially if you have to carry them in a "ready to use" position.

Norwegian infantry patrolling in Afghan mountains would much rather carry the G3 over the G36, even though they could have carried a much lighter load or more rounds if they did. But they felt more safe with the G3, because they knew that it had both range, accuracy and stopping-power superior to the local AKs. The same thing you Americans have discovered. You are wiping the dust of the venerable old M14. While nothing is wrong with the M16 or M4s, the real problem is in the capabilities of the calibre.

We can agree on one thing: 5.56mm is an asthmatic round, while the 7.62 is quite a bit on the heavy side. Something in  between would be "perfect". I would actually prefer the 6.5 Grendel, as not to decrease capabilities compared to 7.62. However, from a 5.56 side of view, a 6.8SPC would still be increasing capabilities dramatically. Also trigger-discipline could keep ammoconsume down, especially if the troops trust that the rounds will penetrate walls, unarmored vehicles and vegetation without big problems.

Yes, but what you are failing to see, to a degree, is that

1) The Stupid Americans (me and Ike, and Cleatus) are generally paying the largest amount for small arms development.  

2) This allows us to force calibers such as the 5.56 on NATO, to the point that the French get pissed off and leave.

3) Americans are fat as a culture and do not have guys named Kjetil and Eirich and Bjaerne who grew up skate skiing and can catch 200' of air on their telemark skis.  

The only Americans I know named Ivar and Lars are from Petersburg and have a radio show where they call themselves  "Big House" Ivar and "Lemon Creek" Lars because of their prison history.  Like 99.9999% of Americans, I do not think that they randonee ski

Americans fucking drive everywhere, and do not use Akjas or whatever you call them in Norge when you go to the supermarket in the winter.   Hell, we even drive to the gym where we run around like gerbils on some treadmill.  In Sweden, the only fat people are the chicks who work at McDonalds at the Stockholm train station, and the Gypsies.

So basically as I stated above, Norwegians and US special operations will use what they want, and will probably use 7.62 "nato" or .280 Brit or Grendel or .276 US.  

But the rest of the mechanized squads will continue to use 5.56.  And considering that they are packing laser designators, GPS receivers, sat phones and the batteries to power all the electric junk, I think that 5.56 is not such a bad thing.

Especially when you have an AC-130 providing accurate 40mm Bofors or 105mm rounds from above.

Despite the perceived or real shortcomings of the 5.56mm, American forces are still doing reasonably well in their overall military objectives.  I think that the place of the rifle is more sentimental than real, except for specific situations, for example, when your batteries run out, your microprocessor fails due to vibration or the hydraulic reservoir on the CH-47 finally runs dry in flight.  

Now I get into my Chevrolet Tahoe and drive 1.5 hours to inspect the forest.

BTW, I am not even .5% of an expert in this area.  But after about 100 years of very careful and enthusiastic small arms development, I think we conceptually more or less peaked out in about 1975 with the Steyr AUG.  It is far from perfect, but it comes closest to a configurable weapons system.  

Well, half of us Norwegians aint that smart either, voting for a socialist government...
And we actually pay for cleaning up Russian pollution inside Russia, while the Russians factories earn great amounts of money, and they even start construction of new submarines...hey
For combat, a more powerful round would be much better, as you won´t have to wait for the enemy to emerge from cover to kill him. You simply fire through the cover. This is actually very clear in FIBUA. If you have a M249, you will have to aim for a window, and keep firing until the enemy shows up and you eventually kill him. With the M240, you fire on the wall around the window, as the bullets will penetrate the wall, and be able to kill anybody hiding behind it. This saves a lot of rounds, and is much more efficient.



Schulze:

You mentioned that a carbon-fibre shrouded barrel will dissipate heat fast enough to not need barrel changes... This puzzles me, as I believe carbon has a relatively low heat-capacity. This is because there are at least three major factors involved in the rate a barrel cools down.

1: The surface-area of the barrel. Fluted barrels dissipate heat faster than normal barrels because of their increased surface area.

2: The difference in temperature between the barrel and the cooling-medium. In this case air.

3: The heat-capacity of the cooling-medium. Water has a much higher heat capacity than air, thus it can cool a barrel much more efficiently.

This leads me to the conclusion that a carbon-fibre shrouded barrel will get hot very fast, but will also cool down very fast. The problem would be if the rate of fire is so immense that the barrel can´t cool down as fast as it´s heating up. Then it´s very easy to get the barrel overheated, and at best only ruin the accuracy of the barrel.  

Btw: Thanks!

From http://www.ms.ornl.gov/researchgroups/cmt/CFCMS/TMS.HTM:

"Surprisingly, studies have shown that the thermal conductivity of a composite often depends more on the matrix than on the fibers. One possible reason is that often some of the fibers are broken and are thus discontinuous down the length of the composite, reducing thermal transport. Therefore, when a high thermal conductivity matrix such as graphitic carbon is used, not only do the fibers contribute to high thermal conductivity, but the matrix does as well. Since the thermal conductivity of graphite is higher than that of any metal, carbon/carbon would appear ideal for high thermal conductivity composites."

Also, I recall that in Desert Storm, the US dropped carbon fiber filaments on Iraqi power stations causing the power stations to short out and temporarily be inoperable.  so they can at least be good conductors of electrons.

Like you said, though, heat capacity may be important, and if carbon composites are not able to speed up heat transfer to the air compared to steel in the same applications, one wonders if there is an advantage to carbon fiber aside from lighter weight and possibly stiffness.

Iwould add that I would be very skeptical of extensive use of carbon fiber in abusive conditions.  Perhaps I am being excessively conservative, but a matrix layup would seem to have substantial potential for mislays, and I question whether it can be cost-effective.

You know, I'm still not totally sold on this concept. I still think that for such a weapon belt wins unless you start looking at the G11 idea, which is, sadly, dead.

Although I think dobrodan, good first post btw, tosses away the FG42 idea. Why not a sidemounted  box mag or drum?

Holy crap, posts that involve thinking, logic, and educated discussion....did I accidentlaly leave AR15.com???

A very interesting treatise/proposal you have there.  I need to abosrb it a bit before commenting but wanted to tag thte thread so I didn't lose it.

[ETA]  OK, a thought or two.  I think the overall concept is very interesting.

As an addendum to your proposal, I would recommend a weapon that has a quick change barrel.  the advantages of this are twofold.  #1, very easy to swap a barrel when it overheats.  #2, you could have a long autorifle barrel, and a short CQB barrel.  

QC barrels desins can be quite simple, The MGI barrel change system for the AR being a good example.  Another simple mehtod besides the "clamping cams" is simply an interrupetd thread barrel/barrel extension and a stud that is depressed to allow barrel rotation.

Great discussions, thank you all.  This is what Im looking to learn.

I'd like to revisit the concept of the M16 LMG.  I think the M16's 30 round mags are perfectly suited to this role.  The only problem is dealing ith heat.  I think the M249 has shown that M855 is capable of the LMG role.

I would also like to see the M16 LMG concept revisited. With the advent of the LMT MRP and MGI QCB, as well as the upcoming Leitner-Wise MRS, the ability of the M16 to change barrels is now available, a handle just needs to be attached to the FSB or barrel to facilitate a rapid swap. Additionally, I've read some positive things about the heat dissipation capabilities of carbon-fiber wrapped barrels. If gas tube failure is an issue (just speculation on my part, don't know that it is or would be), the HK, LW and POF piston systems should alleviate this, and I know that MGI has developed carbon-fiber wrapped gas tubes for extreme use. I have also read of MGI's work with a bolt and carrier system that fires from the closed position in semiautomatic fire and from the open position in full auto.  Furthermore, if the bugs in the BETA CMAG system could be worked out to where their reliability was similar to the USGI 30 rd. model, then I think the proposition of a redesigned M16 LMG would be much more viable than in the past. If such a system can work well, then retrofitting would be as simple as swapping a new upper onto all of those old M16A1 lowers! Not to mention that all personnel trained on the M16 platform would at minimum be familiar with the manual of arms and basic field-stripping protocol.

The FG42 was a revolutionizing rifle when it arrived. The design, however has a few minor flaws:

It´s a little bit more complicated to insert a fresh mag while moving, compared to top- and bottom-fed guns.
Also the CG will move when you fire the gun, meaning that you will have to counterbalance it continously to get good accuracy.
But the most important thing is that the gun is not ambidextrous to the co-gunner, as it´s only practical for him to assist from the left-side-only. Also, to insert a magazine horizontally for a co-gunner in the prone position is a bit difficult.

The Bren-design is however not ambidextrous to the gunner in its original design, but to fix that you simply add a right-side optics-mount.
Also, a periscope-sight should be made available for most military guns, being able to let the gunner fire accurately when suppressed by enemy fire.

As I´m extremely familiar with belt-feds, although they usually are extremely reliable, they tend to have a lot of jams when used in less than ideal conditions. Because of the feeding system they are very complicated and heavy compared to mag-fed guns.

About the QCB, I would like the rifle to be as simple as possible, but I think hot-swapping of barrels is not necessary if the gun is not used as a MG. My idea is that instead of 1 or 2 MGs in the squad, you add 3 or even 4 "ARs", thereby having the same number of barrels being able to fire aimed auto-fire. As this would mean less intensive firing per gun, better accuracy than normal would be the result, as the 3 or 4 gunners would be responsible for the same amount of rounds per time, as 1 or 2 gunners would be with MGs.

QCB-ability tends to add a bit of weight to a weapon. First because it needs a sturdy mechanism to hold the barrel in place, and secondly because it would be advisable to have a insulated handle on the barrel, to avoid the need for heat-resistant gloves. It would however, be a good idea to base the "AR" on a rifle which has a quick "in-the-field" changing ability, like the SCAR or XCR, enabling variations in barrel-length and calibre.

A carbon-fiber shrouded barrel could maybe tolerate higher temperatures than steel-barrels, because the carbon-fibres don´t soften as steel would at extreme temperatures. Thereby the carbon-fibre is supporting the steel-internals from rupturing. But, the elevated temperatures would probably degrade the quality of the steel, shortening the barrel´s life-time. Not a good thing for an already very expensive part.

I have read a test that USMC ran, testing the M249 against a Colt LMG, a G36 LMG and an Ultimax LMG. The Colt scored highest in total, while the M249 scored lowest. The soldiers did however prefer both the Ultimax and the G36 before the Colt, and the M249 scored least again. The reason for many of the soldiers to dislike the Colt, was that it was too similar to the standard M16, while its method of function was not the same, leading to a lot of negligent discharges.

The problem with BETA CMAGs is in my opinion that they are too bulky, and probably doesn´t tolerate the same amount of abuse a normal magazine would have tolerated, and if destroyed, it could have locked up 100rds from use. While I like the idea of the drums, I would not have wanted to use them in an assault, but rather in a defensive position, as they would probably be more reliable, and not increase the carrying-weight of the rifle.

The Bren was a fabulous weapon for a lot of reasons, but having shot one (under admittedly ideal circumstances), I hated having the mag in the way and the offset sights.  I'd also imagine that it would play hell with larger optics like the ELCAN.

Bottom mounting is just as bad as the popularity of 20rnd AR15 mags for prone shooting can testify.

My vote would either be for a side mounted magazine, or a wide, flat drum mag on top like the Lewis.

My reservation about a side mount mag would be in the decreased ability to hug cover on the side of the magazine.  This would be especially so with a longer 40 round box magazine unless a quadruple stack arrangement were successfully implemented.  

I think the overall direction of this thread is this:

-Increase bullet size and op system to handle a heavier bullet than the 62gr 5.56.

-Retain fixed barrel, unless QCB interface is relatively light.

-Mag position seems to be inconclusive-- I would make the argument that in a potentially muddy, snowy, or frozen rain zone, I would not want a top mount magazine.  Precipitation falls down, not up.  

so my question is, apart from the caliber change, what have any of us suggested here that does not already exist with systems like the Colt LMG and the Steyr LMG or the L86A1 LSW.

I say very little.  

This is an interesting topic.  I was wondering if the Ultimax drum magazine would be a better alternative to a CMAG?

No idea, but needing more than your bare hands to depress the spring in the Ultimax does not sound like a field expedient solution.  Would be handy in kill em all situations.

If I was to take a wild guess, i would bet the reason the German saddle drum worked better is 1. it was made of metal and 2. the cartridge geometry was more conducive to the roatary drum feed magazine.  I would also hazard a guess that the spring was pretty damn strong.

The main problem with shorter/fatter cases is that they do not work well in automatic weapons.  I believe Ian Hogg's book "Machine Guns" (By Greenhill IIRC) covers the technical reasons in some depth if anyone wants to know exactly why.  From what I remeber, it has a lot to do with metal properties, the pressures vgenerated,  and the ratio of length to diameter of cartridge, and basically is an issue of having to balance out overcoming cartriges sticking in the chamber versus teraing them apart during extraction. I really wish I had that book handy at the moment, sorry I am at work.

The issue of a top feed magazine has both its pros and cons.  On the pro side, you can swap magazines very quickly without adjusting the weapon.  It also makes it easy for an assistant gunner to do mag swaps.  Finally it has the advantage of allowing rather long magazines without interference from the ground.  On the con side, it blocks quite a bit of the gunners field of vision, which would seem to be particularaly bad at closers (CQB) ranges, and also would make optics mounting difficult at best.  Before anyone poo-poo's my CQB comment with the response that "automatic rifles are not for CQB" please take in mind that an automatic rifleman will be expected to do CQB with the rest of the squad regardless of the effectiveness of his weapon to do so. If there is a way to improve its efectiveness in all roles without reducing its effectiveness in its primary role, so much the better.

Quoted: please take in mind that an automatic rifleman will be expected to do CQB with the rest of the squad regardless of the effectiveness of his weapon to do so........

This is yet another reason I believe a quick change barrel system is viable, as you could issue a 10 - 12" barrel for CQ work, and a 16 - 20" barrel for GP/perimeter work. With the shorter Para models of the M249, the end user is limited to a 14" or so barrel; good for FIBUA/MOUT work, but when distances increase, especially with M855 Ball, the fragmentation envelope is limited much more than a longer barrel would be. A system using throwlevers, such as the MGI  or LW (on an M16 based LMG) would allow for rapid barrel replacement when the situation dictated, with a negligible weight gain.

During CQB, it´s my opinion that if proper training has been given, the topfeed will block very little of the gunners observation, unless the target is closer than 3-4m. This is because it´s a good idea to keep both eyes open when in a CQB situation. I myself keep both eyes open on longer ranges as well, without any accuracy-problems, with and without optics. Also, you usually keep the weapon at a 45deg angle when not engaging a target, keeping the magazine out of the way.

The "AR" would probably be better for CQB than a M249, given its lower weight, making it easier to carry, and faster to aim. I would prefer a barrel of 18-20" as a standard barrel, with maybe a 14" barrel for normal FIBUA. I would however, probably prefer a very shortbarreled assaultrifle or SMG for roomclearing, because of smaller size and less weight.
A lightweight QCB-system would be to prefer, unless the "AR" then would routinely be used in a heavier role than intended, thereby needing to hot-swap barrels in the field. A extra (shorter) barrel should be made available for mission-specific or stationary-role only. Thereby avoiding to add more weight to the soldiers´ already heavy burden.



Unfortunately, the Norwegian army only have black stocks for the MG3. So, unfortunately, I don´t have any green ones...