Grendel as a Universal Infantry Cartridge

[stanc]

So the main selling points for a new cartridge will IMO be to replace 7.62mm in portable guns for dismounted infantry while saving a substantial amount of weight, and to standardise on one calibre for such troops.

7.62mm would remain in use for a long time in vehicle mounts, but that doesn't matter since they have their own ammo supply line. 5.56mm would probably hang on in more of a PDW role in lightweight carbines in non-infantry units. But the idea is that the line infantry would only carry weapons in the new calibre.

I understand that. I'm just very skeptical about the chances of getting the US/UK/NATO to adopt another caliber that doesn't replace one of the current standard rounds. That would make for a 3-caliber system, to which I see only historical opposition.

[JASmith]

...203's and similarly re-packaged GL's are limited to 400m effective range, and most grenadiers can't make hits under stress much past 200m...

If I understand the ballistics correctly, the 40mm grenade effective range is driven by a very low muzzle velocity. Increasing the velocity even a little bit would make the recoil too much for shoulder firing. I'm also guessing that the elavation needed for 200 meters is about fifteen degrees and goes to about 35-40 fro 400 meters. These high elevations both make precise aiming a challenge and give plenty of time for the wind to have its way with the projectile.

That's part of reason behind the question about 20-25 mm grenades. The smaller weight projectiles can be launched at a higher velocity while keeping recoil manageable. And yes, the "Star-Trek" aiming devices are big and clumsy today. They should become more compact with time for two reasons. First, the electronics will become more compact. The second and more important reason is that folks will realize that too much is being asked of fancy technology. When this happens, the feature count will drop to something more like a basic range finder and ballistic computer to get the elevation solution displayed in the reticule. The hardware for basic laser range finding and sight elevation computation takes up very little space and weight as suggested by the existence of commercial riflescopes doing just that.

Hence the 20-25mm grenadier has a chance of getting a weapon that weighs about the same as the M4 with its claptrap and can carry 4-6 times as many rounds as can be carried for the 40mm. This means that he can afford to shoot a few more grounds making the first round hit question less important. Further, he and his buddies are likely to see where that grenade lands and explodes, so better references are available to getting a second round hit. The second round hit probability gets even better if his weapon is a repeater so the second shot is taken while the wind remains more or less the same.

[bwaites]

The issue today isn't the electronics on these optics, its the lenses/screens. To make them usable, they have to have a big enough screen/lens combination to be seen. Since the human shape and eye aren't changing very rapidly, we are locked into a certain size, regardless of how small we shrink the electronics, (which don't take up much space at all right now!).

The game changer will be some kind of screen that drops in front of the eye and creates a "Heads Up" kind of display, based on where the weapon is pointed, similar to what is used to slave the machine guns on helicopters now. Optics on top of guns will then go away, with only some kind of highly sophisticated sensing unit. Ideally, this will include thermal, optic, and starlight type of information. The electronics are available, the sensors are available, but the combination applied to boots on the ground hasn't been maximized.

[stanc]

...the 20-25mm grenadier has a chance of getting a weapon that weighs about the same as the M4 with its claptrap and can carry 4-6 times as many rounds as can be carried for the 40mm.

That sounds a bit optimistic to me. The XM25 is much heavier than the M4/M203 or M4/M320. And IIRC, the 25mm round weighs 1/3 to 1/2 of what 40mm HEDP does, which means he could carry 2-3 times as much ammo, not 4-6 times.

Interesting feedback on XM25 use, for those who haven't already seen it: http://kitup.military.com/2011/02/inside...istan.html

[Tony Williams]

While there are some significant advantages to these developments, we don't have a system that will compensate for wind factors downrange

We don't at the moment, but that's the intention. From my web article:

"Even more remarkable is the LIDAR (Laser Identification Detection And Ranging) unit developed by the Israeli Soreq Nuclear Research Center. This works by firing a laser beam at the target, the reflection being captured by an array of photodiodes. Fluctuations in the signals received by the photodiodes are used to detect the direction and velocity of any cross wind. This may well have an application in the DARPA One Shot next-generation sniper scope program. The One Shot program is intended to enable snipers to be on target with the first round, under crosswind conditions, up to the maximum effective range of the weapon: a target of 65% probability of a first-round hit at up to 1,500 metres has been set (presumably when using large-calibre long-range sniper rifles).

The goal of the DInGO program is to develop a rifle scope that will turn every soldier into a marksman over the full lethal range of combat rifle, allowing accurate engagement of targets by automatically making all of the ballistic adjustments needed to hit the target."

Just as relying on GPS for your primary navigation solution is an absolute mistake without an understanding of map-reading, compass use, terrain association, pace count, etc., relying on technology for a firing solution without an underlying experience base with intermediate range shooting (that is only taught in sniper training currently) is a mistake.

You raise a very interesting point there. Warfare is becoming more and more reliant on electronics. To what extent should we have low-technology fall-back systems in case the electronics fail? In many instances there is no alternative - if your radar set goes down, you're not going to be able to fire those anti-aircraft missiles or direct your own fighters. Soldiers are already expected to learn a huge amount more than they were a generation or two ago. How much more can they be burdened with? As you know far better than I, sniper training is not something you can pick up in a couple of range sessions. Maybe we just have to accept that if the fancy sights stop working, the soldiers are going to be limited to BUIS and an effective range of 300 m or so.

Also, with the nature of a high-stress engagement where the Pashtun fighters have purposely initiated a far ambush outside the effective range of even optimistic effective ranges for the 7.62 NATO, no shoulder-fired weapon other than the M107 and maybe a .338 LM will begin to even touch them at the ranges they like to initiate at. These engagements are usually resolved with CAS, mortars, or artillery.

I think that the problem has been with engagements which are outside the effective range of 5.56mm, but not 7.62mm - i.e. 400-800m.

CAS, mortars or artillery may not be immediately available, or apprpriate to use if they are, depending on the ROE.

[JASmith]

One of our challenges is to identify the time frame for any potential new cartridge.

Once that is done, the next step is to identify the other technologies that might be mature enough to use in the same time window.

That fancy LIDAR, for example, has to go through a lot of maturation before it becomes a sensible tool for the elite soldier. At some point, it might become suitable for the average grunt.

Another example is shown by the emerging 20 - 25 mm grenade launchers. The first attempts have these things being told when to detonate so they'll be more effective inside rooms, over foxholes, etc. While that added finesse will improve effectiveness, it is also delaying by five or more years the availability of a dumb version that will help battlefield effectiveness.

My intuition suggests that these contemporaneous technology introductions will significantly reduce the pressure to field a ubiquitous 800 meter rifle. That region will be covered by other organic assets like the lighter grenade launcher and the modern LMG LRRPF52 brings to our attention.

[LRRPF52]

Even if I waved a magic wand and took the Israeli (stolen tech from US, France, Germany, South Africa) and miniaturized it into something no larger or heavier than an Eotech, the basic premise by which it operates is flawed for in at least one major way: bullet trajectories are not linear like a laser, so the higher area of their flight path is where you need to compensate for wind for long-range shooting, not what is just seen along your line-of-sight. Would it help achieve a higher hit probability within 500m, maybe, but if ends up in actuality being a Clingon-sized Star Trek scanner like the PVS-10 abortion, it will get left at the FOB or bottom of the rucksack at best.

The guys I know that are truly gifted at making 1st-round hits at extreme distances spend the majority of their free time at the range, and usually make those shots when the wind is tame in the early morning. The bullet spends almost all of its time outside (above) the line-of-sight in those solutions, and I have a hard time seeing how a LIDAR will compensate for multiple value winds. Sounds like a great spiel to get some big Pentagon dollars though...the big contractors will jump on it and get some Colonel getting ready to retire to declare it the cat's meow, even though he couldn't zero a regular service rifle, let alone explain with any degree of expertise what long-range precision marksmanship is about. Forgive me for being cynical, but I've seen this rodeo before, and it always ends up with the rider being tossed off after he gets into the real corral of Joe taking it overseas. The AN/PVS-10 Day/Night Sniper Optic for the M24 is a perfect example of that, since I saw it paraded at AUSA in 1994, and saw our Snipers with it in 2003 for OIF1...couldn't hold zero to save its life.

The same things is happening with the new Grenadier LRF ballistoc trajecory gadgets right now. If they would have spent the money on sending Joe to the grenadier range until he can put a 40mm HE round through a window at 150m reliably, and make kill zone hits out to 400m consistently, we'd have a better real-world solution. They could learn from the way a certain unit at Bragg runs their grenadier ranges.

In the meantime, a lightweight Multi-role LMG with constant recoil would be a plug-and-play solution with the current defunct leadership command climate, and entry-level soldier skills. Load, point, spray, controllable beaten zone, badguys die...simple.

[Tony Williams]

Even if I waved a magic wand and took the Israeli (stolen tech from US, France, Germany, South Africa) and miniaturized it into something no larger or heavier than an Eotech, the basic premise by which it operates is flawed for in at least one major way: bullet trajectories are not linear like a laser, so the higher area of their flight path is where you need to compensate for wind for long-range shooting, not what is just seen along your line-of-sight.

That's a good point. Although to be fair the target is a 65% first-round hit probability, not 100%!

If a device like this enables the average Joe to get the bullets in close proximity to the target, that may still be worthwhile.

[JASmith]

I think the point LRRPF52 makes can be summarized with the observation that experienced soldiers know that "shit happens." Hence any overly complex system has to be viewed with suspicion unless and until it is proven as being reliable and effective.

The current incarnations of these sighting systems are clumsy appearing and, judging from the reports of soldiers who have combat experience, are clumsy to use.

That doesn't mean that they won't pass muster in ten years, but it does mean that we need to work a common time frame for the discussion.

Also, we need to define the background experience the new recruit is likely to have and how much effective weapons-handling skills development he or she will enjoy during that first term of active duty. First, they will have killed about a zillion Gorgon/Dragon/Evil Things by putting a dot on the image and punching a button. That gives an advantage over the inner city kids of 80s who didn't have all the gaming experience. It is also part of why the red-dot sight works as well as it does for the younger troops. They are, however, still ill-prepared for precision shooting even in the mode of place the pip on target, hold, and squeeze.

The ability to get a steady sight picture from a stable firing position while squeezing the trigger is an advanced marksmanship skill.

I further believe that the average soldier does not need this skill when just the assets of a platoon are considered. As much as I personally dislike the varmint cartridge, the 5.56 does have a good track record where it works.

We have covered the intermediate range with 7.62mm, grenade launches, and LMGs. These are the roles and applications where new cartridges, grenades, and sighting systems may get traction over the the coming 5-10 years.

[LRRPF52]

When I look at automatic weapons with a constant recoil operating principle, they are plug-and-play designs that a soldier with no training can pick up, and put to use immediately with no other instruction than how to load and operate the mechanism. Since there is no real disruption of the sight picture with a constant recoil machinegun, you just walk the rounds into the target with immediate correction feedback. You don't even have to muscle the gun into a stable firing position, because it just tracks where you point it.

You can't fix cave-man, but you can make toys that cave-men can play with. If you give cave-men a Clingon Star Trek Scanner, it will be a paper weight or club.

[BluntForceTrauma]

Here's another chunk of anecdotal evidence speaking to long-range firepower needs in the hands of soldiers.

Link: http://kitup.military.com/2011/12/tank-snipers.html

Money quote: "More and more reports are coming out telling us that the Taliban in Afghanistan has finally figured out the limited range of American rifles and other small arms. Acting accordingly, we are told that they are maintaining as much stand off as possible when engaging US forces, remaining just outside the maximum effective range of our soldier’s ammunition while firing at them with heavy machine guns and RPGs. The Carl Gustaf has the potential to change that when employed properly. Existing systems…such as the M141 Bunker Defeat Munition, M72 LAW, M136 AT-4 and the SMAW, are only effective inside of 500 meters. The Army says the Carl-Gustaf [max effective range 1,000m] is more effective than waiting on mortars and less expensive than artillery or Javelin missiles.”

John

[JASmith]

John,

Thanks for pointing that out -- even I keep forgetting that we need to discuss combined arms as we go through this discussion.

Cheers!

[stanc]

Here's another chunk of anecdotal evidence speaking to long-range firepower needs in the hands of soldiers.

Link: http://kitup.military.com/2011/12/tank-snipers.html

Money quote: "The Army says the Carl-Gustaf [max effective range 1,000m] is more effective than waiting on mortars and less expensive than artillery or Javelin missiles.”

According to militarytimes.com, the M3 will be fielded to the 82nd Airborne. In the late 1990s and early 2000s, I participated in a forum composed mostly of veterans, from sergeants up to a general, and we tried to get the Army interested in the M3. (I even had an article in Infantry magazine that in part proposed this weapon be acquired for the 82nd.) That the leadership has finally seen the light is refreshing. Maybe there's hope for 6.5 Grendel...

Below: The high explosive, air burst round ought to be just the ticket for "discouraging" RPG gunners standing off at 900 meters.
[video=youtube;IBbxS78kbZY]http://www.youtube.com/watch?v=IBbxS78kbZY[/video]

Below: At 1:01 the HEAB fuze setting is shown.
[video=youtube;XNxFiGvhLXE]http://www.youtube.com/watch?v=XNxFiGvhLXE[/video]

[LRRPF52]

I was going to say that Ranger Regiment has been using the Carl Gustav for quite some time. Those are some impressive warheads.

The Taliban and their Mujahaideen origins are well aware of small arms ranges, and seem to favor far ambushes outside of 800m+, especially if Dshka's are available. You can use thermals with trail teams as you bound, regardless of time of day, to detect human signatures, and initiate on your terms, but most small unit leaders think too much in a very small box, and don't use the tools available to them. This problem is systemic and is found throughout the US modern war experience.

[stanc]

Finally came across a combat video with a carbine fired full-auto (@ 1:35, below).

Still haven't seen any speed loading, though. Mag changes in this vid are slow and deliberate, as in all previous.

Note the rifle-length rail and lack of BUIS.

[video=youtube;JwDxpST8EU8]http://www.youtube.com/watch?v=JwDxpST8EU8[/video]

http://www.youtube.com/watch?v=JwDxpST8EU8

[Variable]

Pretty cool vid Stan. It's pretty interesting. I'd like to have a can on (if I were the guy shooting through the portal) to reduce my dust signature and all of the debri that was kicking up---- BUT I'm a long way off of ever qualifying to walk in those guys shoes, so I have no idea if it would have been practical or not. I'm not at all qualified to even comment intelligently, and certainly not to critique or criticize, so I'll just ponder.

I do know I'm dang sure jealous of their 203s, that guy's Specter sight, and I wish I had their ammo too though.LOL!

[stanc]

A lot of military users are now starting to test the 6.5 mm Grendel. Fired from a 24" barrel, it provides impressive long-range performance, which is superior to that of 7.62 mm NATO. From a 16.5" barrel, it is less good than 7.62 mm NATO, but far exceeds 5.56 mm NATO.

Could a militarised 6.5 mm Grendel be an ideal choice? I don't know, but expect to hear a lot more about this round over the next 12 months or so.

http://forums.delphiforums.com/autogun/m...sg=5699.59

[Trooper]

Look to have a general purpose (universal) cartridge it is going to have to be between 6.5 and 7mm. The 6.5mm works better due to less recoil.

The next aspect is getting the round to 2500 fps out of the barrel using a 140 grain bullet. That is the standard, set by the 6.5x55 Swedish Mauser. So far the .260 Rem, the 6.5 Creedmoor and and the 6.5x47 Laupa meet those requirements but with longer cases. As do wildcats like the 6.5 BRM which is based on the .30-30 case. The problem is that we can get a 140 gn. bullet to go 2500 but it takes a longer case than would fit into the current AR platform.

So could we make 6.5mm GPC that pushes a 140 gn. bullet 2500 fps? And make it smaller than a .308 (7.62x51)?

[LRRPF52]

The Grendel is capable of pushing a 140gr to 2500fps from a stronger action, but with a different COL. The problem is, you don't want a 140gr for riflemen. Too much recoil, too much weight.

130gr is the maximum you really need, and even then, I don't want riflemen hosing away in close quarters with that load. 130gr is perfect for a belt-fed, and can be pushed to 2600fps from a stronger action with 2.400". BjornF16 has done just that with his Savage and a 20" barrel.

[SHORT-N-SASSY]

Look to have a general purpose (universal) cartridge it is going to have to be between 6.5 and 7mm. The 6.5mm works better due to less recoil.

The next aspect is getting the round to 2500 fps out of the barrel using a 140 grain bullet. That is the standard, set by the 6.5x55 Swedish Mauser. So far the .260 Rem, the 6.5 Creedmoor and and the 6.5x47 Laupa meet those requirements but with longer cases. As do wildcats like the 6.5 BRM which is based on the .30-30 case. The problem is that we can get a 140 gn. bullet to go 2500 but it takes a longer case than would fit into the current AR platform.

So could we make 6.5mm GPC that pushes a 140 gn. bullet 2500 fps? And make it smaller than a .308 (7.62x51)?

It's been reported that 2650 - 2700 fps, with the 139-grain Lapua Scenar projectile, has been achieved, from a 22" bolt-action rifle chambered for the 6.5 Grendel. Was that 139-grain Scenar loaded to AR-15 magazine length, or extended? If extended, to what overall length?

It's been reported that "Big Bolts" can operate at/up to 60,000 psi, in the standard-length AR-15 action. Unencumbered by the limitations the laws of Bolt Thrust impose on the 6.5 Grendel, in the standard AR-15 Bolt-Barrel Extension, what velocities can be achieved in a "Big Bolt" AR-15?

ETA: LRRPF52 Reply was posted, while I was typing mine. I think it's fair to state that his suggestion represents the solution.