Requirements for Replacement of Currently Issued 5.56 M-855 and 7.62 M-80.

[LRRPF52]

Yes, XM29 was cancelled. I was thinking of it since one of the Scouts in my Brigade in 25th ID died testing it in 1998-99 when the programmable munition detonated while he was aiming it. The new one is the XM25 without the PDW component.

M193 (55gr) out of an M4 with 1/7 twist is listed as 3050 fps, while 62gr M855 is 2920 fps. I'm sure some variances would put the ES to possibly 50 or 70 fps less, but it is still a hot load with brutal wound ballistics within 100m, and very difficult to match within the size constraints.

I just don't think a new LMG should be limited by AR magwell dimensions, since it won't and shouldn't matter if the LMG uses linked ammunition anyway. It also shouldn't be limited by 7.62 NATO weight penalties since we can exceed M80 ballistics with lighter projectiles.

I would leave 5.56 NATO alone, other than making Mk262 more available to DM's, and upgrade the M4 to a rifle-length float tube and quick-barrel change system possibly. The 3-round burst mechanism should be replaced with the original AUTO mechanism, so the pull weight is no longer affected by that horrible burst counter wheel and the additional disconnector. The real area of focus should be on making a lightweight LMG that exceeds 7.62 ballistics, and can be wielded in Close-Quarters as well. That pretty much forces us in the direction of a Bullpup LMG design, which is hard to belt-feed, but I have some ideas.

LRRPF52

[LRRPF52]

I lean towards keeping the belt-feed system for machineguns since we can replace both the SAW and the M240 with one weapon, that will exceed 240/7.62 capabilities from a platform that weighs almost 1/3 the 240B (27.6lbs). Having humped both the SAW and the 240 and managed them from a Rifle & Weapon's Squad Leader duty position, I lean heavily towards a belt-fed machinegun over a mag-fed Automatic rifle any day, especially if the LMG can weigh about 10 pounds, which has already been accomplished with several designs. The KAC LMG, Shrike, and Stoner 63 are all examples of very lightweight belt-fed LMG's.

We have to balance out the weights and weapon profiles that every Joe carries, and I argue in favor of moving the current imbalance of the SAWs and 240's towards the profile and weight of the M4. If we do that and increase our ballistic potential (both totally feasible), we have made leaps and bounds in the structuring and mobility of dismounted Infantry.

LRRPF52

[JASmith]

Gents,

I'm in favor of a 3-caliber (really 5+) system for shoulder-fired weapons for dismounted infantry soldiers...

This looks like an excellent start for a thread discussing systems that fill the need being defined in this thread.

Doing so would help keep focus on each thread topic.

Any of us can do it. Probably the simplest way is to quote LRRPF52's 3-cartridge discussion along with a prefatory comment and away we go!

Cheers!

[stanc]

The real area of focus should be on making a lightweight LMG that exceeds 7.62 ballistics, and can be wielded in Close-Quarters as well. That pretty much forces us in the direction of a Bullpup LMG design, which is hard to belt-feed, but I have some ideas.

I dunno if a bullpup is feasible, but a semi-bullpup GPMG can be done. Actually, such a design already exists.

http://www.youtube.com/watch?v=48pFvx4hlbo
http://www.youtube.com/watch?v=m3T3DY2fR6w

[LRRPF52]

Roger...M60 and FG42 before it are considered "half-bullpups", but I'm thinking of a true bullpup, belt-fed LMG that weighs 10lbs or less. I grew up on the M60 and was kinda surprised when we replaced it with an older design...the MAG58 with the US Nomenclature of M240. The MAG58 runs much more reliably since it has a solid feed tray cover and a long-stroke piston, but the M60 was a much smaller profile to carry, and had what very few GPMG's have-a forward handguard. I do like the M60's quick barrel change latch better than any other. They carried that over to the SAW as well.

LRRPF52

[Tony Williams]

I'm in favor of a 3-caliber (really 5+) system for shoulder-fired weapons for dismounted infantry soldiers:

I don't doubt that your proposals would have advantages over what we have now, although the limited propellant capacity of the 6x35 seems likely to restrict it to a 200m (maybe 300m at the very most) effective range. So it may be necessary to carry more of a balanced mix of carbines and DMRs unless the fighting is all in towns. I agree with you over the .338, by the way, but regard that as being in a separate category.

As a result of my experience in debating these issues with MoD in the UK, I think that the problem which any replacements for just the 5.56mm, or just the 7.62mm, will face is this: yes, you can produce ammo which has advantages over the existing calibres - but the advantages are not so great that they justify the huge disruption and cost of the change.

In my opinion, this is where the single-calibre solution can deliver a more compelling argument in its favour - provided that a satisfactory performance can be achieved. By replacing both 5.56mm and 7.62mm with one general-purpose round, you achieve not just one improvement but "three for the cost of one": lighter weight and recoil than 7.62mm, better range and effectiveness than 5.56mm, plus the various cost and flexibility advantages of having only one round and weapons family rather than two to procure, support, train and fight with.

I would be surprised if the XM29 makes a come-back. It was concern over the effectiveness of the 20mm grenade which caused the increase to 25mm in the XM25, which meant that the 5.56mm element had to go - the weight of the XM29 was already too much, and would have increased still further in 25mm.

As a matter of interest, I spell out my thoughts on the subject of a near-future small arms system here: http://www.quarry.nildram.co.uk/future%2...20arms.htm

[JASmith]

A follow-up thought - given the likely weight of the DMR and the reduced recoil of our general-purpose cartridge, it could also be given selective fire to act as an automatic rifle.

Sort of like a 21st Century BAR!

I had overlooked this comment earlier but just ran across it while reviewing for an update on the requirements descriptions.

A selectable fire DMR rifle with the ability to use the same ammunition as the rest of the squad is truly a neat idea. Had to think about it but I now realize that this would likely give the DMR better capability when things get close.

I wonder how this would mesh with the experiences Gene and LRRPF52 have?

[LRRPF52]

Re: DMR's as multi-role BAR's or LMG's, the Marine's approach to the Auto-Rifleman concept has kind of re-introduced that with the M16-based Automatic Rifle that fires from the open-bolt, but uses a push-rod system to handle the increased heat of frequent automatic fire. As I said, the success of that system will rest heavily upon the reliability of the new coffin mags from Surefire and Magpul, which I have yet to hear unbiased extensive field reports of. I can already tell you that the CMAG fails when the slightest amount of dust is introduced to it, as we were issued a few before deploying to OIF1. Unfortunately, they don't work in field conditions.

To me, a Light Machinegun is all about sustained firepower without the gunner having to reload frequently, and the only systems that do that really are belt-fed, followed by some exceptions with drum-fed. The biggest problems with drum-fed mags is the time it takes to load them plus the carry issues with them for pouches, whereas linked ammo just keeps flowing through the logistics chain and can be fed right into the guns without any extra procedures if need be. It is also much easier to feed linked ammo into the soft bag "nutsacks" we used for the SAW, which several after-market companies run by SF and grunts have mimicked for the M240 and even PKM.

The Finns had a lot of success with the Kp31 9mm SMG using 72rd drum mags, but loading the mags to meet the target-rich environment was problematic for them, to the point that they ran the Kp31 in static positions with an "Assistant Gunner" loading drums for the shooter. They even came up with a plastic loading tool for the drums after the war to have ammo pre-positioned so it would slap right in, versus the tedious task of hand-loading each round. Imagine doing that in -20 and -30 C weather and that's what they did.

A new LMG could incorporate a select-fire mechanism, even with a select bolt-open or bolt-closed operating mech as is currently available with the M16-based LMG's. As you look at what new aiming and targeting systems are being introduced in the future force concepts after Land Warrior and such, this idea might make more sense for an LMG that can also deliver single rounds in a precision mode if needed. If it can be done reliably, without causing more problems with all the small parts, I'm all for it.

LRRPF52

[LRRPF52]

As a result of my experience in debating these issues with MoD in the UK, I think that the problem which any replacements for just the 5.56mm, or just the 7.62mm, will face is this: yes, you can produce ammo which has advantages over the existing calibres - but the advantages are not so great that they justify the huge disruption and cost of the change.

In my opinion, this is where the single-calibre solution can deliver a more compelling argument in its favour - provided that a satisfactory performance can be achieved. By replacing both 5.56mm and 7.62mm with one general-purpose round, you achieve not just one improvement but "three for the cost of one": lighter weight and recoil than 7.62mm, better range and effectiveness than 5.56mm, plus the various cost and flexibility advantages of having only one round and weapons family rather than two to procure, support, train and fight with.

The biggest obstacles to a one-caliber system are the varying performance requirements for a combined arms team. What I want a bullet to do in the house, forest, and city streets from my carbine with riflemen is almost opposite of what I want it to do from my LMG's at 200-900m. The weight penalties to favor an LMG performance envelope prohibit the close-in fight envelope from a practical standpoint. I think of assault rifles/carbines as over-powered submachineguns with the capability to reach out to 300-450m depending on the cartridge, which is really an awesome achievement in the history of warfare. For the majority of practical engagements that a rifleman will use his weapon in, it's hard to find anything better than 5.56 NATO.

I would not pay too much attention to articles that start out with the premise, "Everyone knows the 5.56 is an anemic man-stopper." or, "Soldiers have been complaining since Vietnam about the ineffectiveness of 5.56..." Soldiers have been complaining about everything since the beginning of time, and professional career soldiers in special operations units around the world who have a lot of leeway in which weapons they can use seem to mysteriously choose the M4A1 or Diemaco equivalent, including your SAS & SBS, Aussie SAS, Danish, Norwegian, Israeli Light Infantry & CT units, let alone SOCOM and JSOC. What is it that these guys know-many of whom come from Light Infantry units with real world tours before they go through the selection and training process for those types of units? My position on 5.56 NATO is that it ain't broke, it's plentifully available, and it often blows living tissue apart where it hits within 100m.

Machineguns need to be able to reach out from that point onwards, and Squad/Platoon-level LMG's need to support the fight in urban areas as well. This requires an entirely different animal with regards to trajectory, penetration, feeding systems, etc. To me, it is counter-productive to try to get these two realms to jive together, although the Grendel does seem to be the best compromise I can think of, but I feel sacrifices too much edge off of each to be worth pursuing in that regard, especially since the assault rifle realm is not broken, and the machinegun realm has lots of room to improve in to make a leaner, more lethal fighting force.

While we recognize that it will likely take something revolutionary to replace anything within the current system, replacements are going to inevitably happen at some time, which is why it's important to keep a healthy debate, testing atmosphere, and brain-storming session alive. I thank you all for that, by the way.

LRRPF52

[stanc]

The biggest obstacles to a one-caliber system are the varying performance requirements for a combined arms team. What I want a bullet to do in the house, forest, and city streets from my carbine with riflemen is almost opposite of what I want it to do from my LMG's at 200-900m. The weight penalties to favor an LMG performance envelope prohibit the close-in fight envelope from a practical standpoint.

Granted, the one-caliber approach is not ideal for close combat, but it was used quite successfully for that purpose by US infantrymen in WWII and Korea. And they used a rifle which was nearly four feet long, too!

To say that CQB is only practical with a short-barrel, telescoping-stock carbine and minimum-size cartridge is contradicted by history.

[JASmith]

To say that CQB is only practical with a short-barrel, telescoping-stock carbine and minimum-size cartridge is contradicted by history.

True -- "only practical" is a strong statement in the light of history. One could also note that lessons of history suggest that a shorter weapon with adequate lethality makes the whole chore easier and more efficient...

The points made by Tony and by LRRPF52, in my view, nicely span sensible options. Both have excellent logic and factual support. So, I feel confident that our explorations will result in interesting options to bring into play when the opportunity presents...

[LRRPF52]

Tony,

The Garand was only one weapon in the mix of Thompsons, BAR's, M1 Carbines, and Browning M1919 machineguns...supported by tanks often. Also, the US forces in the European theater entered WWII pretty late in the game, and only faced about 1/3rd of the Wehrmacht, and those forces were often the newly-recruited, recovering injured, youths, and generally ones who weren't fit to be on the Russian front-where the most intense Eurasian infantry battles were fought. Those fronts also were priority for fielding of the Stg44, elite German units, and the main strategic focus of Germany.

Furthermore, they weren't fighting opponents with AKM's and PKM's, so while WWII introduced the paradigm shift of the Assault Rifle, its lessons were largely lost in the US ordnance circles responsible for small arms development, which was painfully evident with the adoption of the single-caliber system with the M14/M60 and the 7.62x51 cartridge. England had a much more viable cartridge at the time in many respected military professionals' opinion, and that was of course the .280 Enfield. The US dominance in systems standardization in NATO basically screwed England, Belgium, Germany, Denmark, Norway, and other countries into adopting the 7.62 NATO as a standard service rifle cartridge, which then became the chambering for the FAL/G1, CETME & later G3, and the other ancillary "Battle Rifles" under the West's influence, which was a shame really, and that's coming from a Yank.

The only redeeming thing for service rifles to come along was the AR15 in 5.56x45, which the US of course switched to quite rapidly after the blatant inadequacy of the M14 in maneuver warfare. Also keep in mind that much of the rice-filled plains in Vietnam provide excellent fields of fire at ranges that would challenge even long range calibers, so it isn't a 100% saturated triple-canopy environment as many would like to brush with one stroke. The AR15 had already become a favorite of the British SAS in Malaysia before major US troop involvement in Vietnam, and continues to be a mainstay as the go-to platform for a small, shoulder-fired weapon for utility across most operational mission profiles in that unit.

I can't tell you enough what a heaven-send it was when we received M4 carbines in conventional and recon units in the US Army. I had been a big proponent of equipping key leaders, RTO's, AG's, FO's, medics, and Scouts with the M4 carbine as I had seen it fielded with 18th Abn Corps LRSC, but knew it would never happen because it made too much sense. Imagine my surprise when I saw our Company Commander walking with one in hand telling my Scout Platoon Leader and First Sergeant about it, and then seeing our entire arms room filled with them! That was one of the best days of mine in the Army, and I was even more surprised when all the M16A2's were replaced with the M4 in Light Infantry, Airmobile, and Airborne units.

Even in the dominant open terrain environments in a high desert mountainous region, small unit tactics in the US system involve a lot of different duty positions that I briefly mentioned-all of which would be ill-suited with a larger caliber rifle with a bigger weight and length profile. The M4 is about perfect for them, since my Medics, Forward Observers, Assistant Machine-Gunners, Ammo-Bearers, Radio Operators, and most Key Leaders will not be even attempting to make hits on individual targets past 50m, let alone 100-300m. We haven't even addressed the Mortar Platoon, Scout Platoon, Company & BN HQ, etc. What rifle would they end up with in a single-caliber system?

Now think about a Leader's recon, which is always conducted before deliberate attacks, ambushes, and raids (which are the 3 types of planned missions or combat patrols dismounted units engage in). During a recon, your job is to move into an area, gather the battlefield info you need, and get back to your unit while remaining undetected the entire time of course. This requires as low a profile as possible, and the M4 fully-supports that role. If chance contact is made, the unit breaks contact using fire & maneuver to get out of the effective range of the enemy as quickly as possible, which usually involves a lot of ammunition being expelled to make the enemy think they have hit a larger force. The most helpful thing in that scenario would be a mix of M4's and a comparable-weight LMG with a short profile that could pump out a lot of firepower, like the Peruvians have with the Ultimax LMG.

Does this shed a little more light on why a single-caliber system doesn't make sense? Remember that there are a lot of guys who compliment the dismounted fighting force with weapons that bring more firepower to bear than anything hand-held, that being the RTO's, TAC-P's, and FO's linked to indirect fire & CAS assets. They are organic and attached personnel (TAC-P's & FO's) as a rule. There isn't this collection of "riflemen versus the world" arrangement, at least in the US system.

I'm not intimately familiar with the British TOE in dismounted units, but I do know enough guys there to be aware that there are a lot of similarities between NATO countries, and there are Mortar sections, machine-gunners, radio operators, forward observers, key leaders, and such. A single-caliber system would do those duty positions a great disservice as well, not to mention all the soft-skill drivers, cooks, mechanics, etc.

If the L85 had been built right from the start, the UK would be in a much better position, and is better-equipped to employ the L85A2 as a suitable PDW for those duty positions today, but it's still illuminating to see SAS & SBS use a heavy mix of Diemaco M4A1-type carbines with UK-made Mag58's as a GPMG for the primary small arms, now augmented with the L129A1.

LRRPF52

[stanc]

The Garand was only one weapon in the mix of Thompsons, BAR's, M1 Carbines, and Browning M1919 machineguns...

That's true, but the Garand was the one standard weapon for the majority of US riflemen. Thompsons were used in fewer numbers, and not by most members of an infantry squad/platoon. The BAR was the squad auto of its day. Your statement not only makes it sound as if the Garand saw only limited use, it ignores my point: that one caliber can be -- and has been -- successfully used for the standard-issue rifle and machine gun.

England had a much more viable cartridge at the time in many respected military professionals' opinion, and that was of course the .280 Enfield.

Which, ironically, was intended for a one-caliber system...

Does this shed a little more light on why a single-caliber system doesn't make sense?

Hey, I'm inclined to agree that -- all things considered -- a two-caliber system is better than a unified caliber. All I'm saying is that a one-caliber system can work well...providing the right cartridge is chosen, that is. Plus, for those concerned with fighting a future enemy equipped with hard body armor, 5.56x45 may be inadequate, and require a much more capable caliber.

[JASmith]

The last several posts shed good light on some long-standing questions.

I have my own prejudices about what might be possible and have voiced them in previous posts in this and other fora.

What I have learned is that we don't know yet what the over-riding issue(s) will be when the opportunity for doing something new arises.

So, we should continue meeting the challenge Gene threw down NINETY+(!!:eek:-EEK!!) posts ago. Once we are able to sort out things like trajectory, the range dependency of required, when we need to stop vehicular IED's, etc., we can see where the technical requirements take us.

Overriding considerations like cost, custom, and plain old-fashioned prejudice will certainly influence the final outcome. So, ALL the cartridge families we define, including the current set, should be considered.

Hence, I am prepared to accept a cost-driven solution that concludes the current mix is pretty good. I can also see the set of constraints Tony has outlined leading us to a single plastic-cased cartridge with multiple loads. The "3-cartridge" model is an intriguing variation that should be tested against the needs we define.

In the meantime, I'm hoping to get a revised trajectory statement that accounts for more of the comments that were presented, and to get a draft barrier penetration requirement statement sometime in the next few days.

[Tony Williams]

I have just received some feedback from interviews with a dozen British infantrymen just back from Afghanistan, who were specifically asked about the calibre issue.

They are comfortable with the performance of the 5.56mm out to 200m, the main problem at longer ranges being scoring hits, partly because the little bullets are so affected by wind drift. (Comment: their standard rifle does of course have a 20.5 inch barrel.)

They dislike the L85A2 because it is so heavy and unergonomic; for those reasons, they'd rather have an M16A4. Their opinion of the L85A2 has put them off all bullpups. (Comment: a pity, since there are much better bullpups around. It is of course possible that if they did get the M16, they would start complaining about the length!)

They very much like the 7.62mm guns: the L7 GPMG (M240) and the L129A1 rifle, which are very effective at all ranges. However, only 30-40% soldiers were capable of getting the best out of the L129A1 in terms of long-range accuracy.

Given a straight choice between 5.56mm and 7.62mm weapons, ALL of them would rather carry 7.62mm, despite the weight and recoil issues.

They would be delighted if someone came up with an intermediate cartridge and weapons which matched the performance of the 7.62mm with significant reductions in weight and recoil. However, they have no experience of such a round and would need to have a lot of successful hands-on experience with the weapons before they would accept it.

[stanc]

I have just received some feedback from interviews with a dozen British infantrymen just back from Afghanistan, who were specifically asked about the calibre issue.

They would be delighted if someone came up with an intermediate cartridge and weapons which matched the performance of the 7.62mm with significant reductions in weight and recoil.

What aspect(s) of performance do they want matched? Just trajectory and drift, or terminal effects, too?

[Tony Williams]

What aspect(s) of performance do they want matched? Just trajectory and drift, or terminal effects, too?

The phrasing was: "as lethal as 7.62mm to 1000 metres"

[LRRPF52]

stanc,

The Garand was the standard service rifle, but was augmented healthily with a mix of M1 Carbines and Thompsons in key leaders' and riflemens' duty positions, in addition to BAR and M1919 gunners. That was a broad mix of weapons capable of CQB out to beyond riflemen distances. A single caliber would have short-changed them, however, they had a logistical nightmare on their hands.

The extreme jerk to the opposite end of the spectrum with the 7.62 NATO single caliber system failed miserably. While a 7mm Enfield would have served the Garands, BAR's, & M1919's very well, it would have hurt the M1 Carbine and Thompson.

Looking into the future, the Russians have fielded the An-94, which is actually their official service rifle since 1986-from what they have told me, but only one regiment has it since there is too much political loyalty to the Kalashnikov design and the "new" AK-100 series. The An-94 is designed to defeat hard armor by firing the 1st 2 rounds on auto at 1800rpm, after which it transitions to a conventional cyclic rate like the AK-74. It is chambered in 5.45mm, and places those 2 rounds within a few centimeters of each other at 100m, so that an armor plate is in a more elastic state when the 2nd round hits, blowing through it.

There doesn't seem to be much knowledge of...or interest in it, since it requires more extensive manufacturing, with a receiver that recoils within a receiver (heavy).

LRRPF52

[LRRPF52]

Fella's

It doesn't take a tour to the Stan to tell you that 5.56 NATO, or pretty much any service rifle cartridge, gets blown around by the wind at distance. Even my .260 is affected by heavy winds, as are .300 Win Mags. The only cartridge I know of stepping up that displays significant resistance to winds is the .338 LM, so even with a 130gr or 140gr 7mm or 6.5mm going 2600-2800 fps, you will still need to be trained in wind-doping to make a hit on-target. Guess how many 1st-term soldiers are trained in wind-doping skills? Less than a fraction of a percent, and those are the very rare few that get any precision rifle training in a sniper billet, or designated marksman course, as the US has been implementing. Proper wind-dope training means on the range, not in some classroom.

The US Marines actually train for wind-doping, but their ranges were traditionally stress-free until recently, when the Corps has undergone drastic changes to their entire marksmanship program. Friends of mine who are in the Marines tell me it's actually fun/stressful and practically-focused, in addition to the traditional course of fire they did all along.

Whether a guy has an M4 or an L129A1, if he can't dope the wind, he's only distributing harassment fire, which only encourages the goat-rapers. Any references to the lethality of 7.62 NATO at 1000m will almost always be from GPMG's in most environments, especially since the wind can be horrendous in open terrain. Equipping the whole lot of 1st-term soldiers with L129A1's will only produce more 7.62 NATO harassment fire, and really suck when it comes time to kick in mudhuts. Muzzle blast from that weapon is guaranteed to cause some serious hearing damage, above and beyond 5.56 NATO, since you need double muffs and plugs to deal with 7.62 in enclosed spaces. It feels like getting punched in the nose when a 7.62 rifle or MG is being discharged in the room you're in.

The LMT .308 (L129A1) is also a beast of a rifle/carbine when you pick it up, unless the UK got some pencil weight barrels, but all the pics show to me pretty hefty pipes that look exactly like the one my friend has. The 16" LMT .308 feels as heavy as my 22" .260 with a very hefty barrel. My barrel is a heavy contour that tapers from 1.2" down to a .880", then steps up to the gas block at .936", and is .9" out to the muzzle. Not fun for a rifleman to carry. When I felt the LMT, I was immediately soured by its weight, which is heavier than normal due to the increased length barrel extension used in the monolithic upper receiver.

While Grendels would make the load lighter than .308, they would be wasting harassment fire at the enemy, so there is a more important training factor to this equation than caliber if you want to increase hit probability with any existing caliber that will fit into a practical rifleman load-out, which 7.62 NATO is not. The only way around this is new technology with near hyper-sonic projectiles that defeat wind deflection with extreme velocity, which might not be a bad avenue to start looking down if armies refuse to conduct worthwhile marksmanship training.

LRRPF52

[stanc]

The Garand was the standard service rifle, but was augmented healthily with a mix of M1 Carbines and Thompsons in key leaders' and riflemens' duty positions, in addition to BAR and M1919 gunners. That was a broad mix of weapons capable of CQB out to beyond riflemen distances.

Yes, there was. However, the key phrase above is "augmented" by Carbines or Thompsons. There were still far more Garands in a rifle squad, than those two weapons. Surely you don't think the (10?) rifle-equipped troops left CQB to just the one guy in the squad who had a Tommy gun?

The extreme jerk to the opposite end of the spectrum with the 7.62 NATO single caliber system failed miserably.

Indeed. But, that's because they insisted on a full-power cartridge, not necessarily because a one-caliber system can't be achieved with an intermediate-power round. The Chinese came so close, with the 5.8x42. They just went a little too small.