How could or should the 6.5 mm Grendel be improved?

[LRRPF52]

The moment we start talking about shooting an assault rifle on automatic is when we head into usage requirement territory. It's really only appropriate in limited circumstances for dismounted infantry soldiers with an individual service weapon:

* Small Reconnaissance elements during break-contact immediate action drills
* When a belt-fed LMG goes down and a rifleman needs to keep up the rate of fire for mainly psychological reasons, if firepower is how one chooses to fight (and lose)

And those are the only times I used the AUTO or BURST (worthless) features when I was in. We did a lot of AUTO fire for IADs as 4-6man recon teams with the Australian Peel, and as a Team or Squad Leader in an Infantry Line Company, I would switch to BURST when one of my SAWs went down during a critical stage of actions on the objective, but it was very rare.

The 7.62 NATO weapons are clearly not feasible for automatic fire, but the AK is controllable in the hands of someone who knows how to drive a gun, with controlled bursts. A suppressed AK is a pussycat with the right can, but suppressors aren't feasible for general issue to entry-level soldiers on the line.

You can change the controllability of an assault rifle on AUTO if someone would actually make an assault rifle using the operating principle of the original grandaddy of all assault rifles, constant recoil combined with a low cyclic rate of fire, which is the most over-looked set of features of the Sturmgewehr Stg44. Watch what I mean when I say constant recoil+low cyclic rate:

http://youtu.be/2jrlCPq5stE

The benefits of a constant-recoil operating system combined with low cyclic rate are more apparent on AUTO than SEMI, and favor AUTO because you don't have as rapid follow-ups in the SEMI mode due to slower bolt carrier velocity. This is where the AR15 shines, because you can hose away with it on SEMI and run extremely fast follow-ups. The Stg44 didn't need a SEMI mode really, because you could touch off 2rd bursts without any real muzzle climb or significant recoil. It's a design that remains ahead of its time.

If you really want a great assault rifle that goes where none have gone before all in one, you use a lengthened receiver where the bolt carrier never impacts the rear like a j(AK) hammer, has a 4-way fire-control mechanism like the Colt Model 605 carbine, with a 2-round burst as the first position from SAFE, followed by SEMI, then AUTO, and able to go in either direction from SAFE.

Use the elongated longitudinal cam pin track of the AR18 with the carrier, keep the reciprocating parts in-line like an AR15 (no off-axis piston, but in-axis), and employ lightweight materials like the AR15 and SCAR. Barrel should be free-floated entirely like AR15's are, with secure mounting, but ease of change at Company armorer level if the average IQ is 85 or more based on pre-Attention Deficit Generation focal span thresholds.

[montana]

LRRPF52 you are the first person I have notice the AR-18 elongated longitudinal cam pin track. This gives a little longer dwell time but I have also felt it helped negated recoil . I was wondering what your thoughts were on this.

[Guardsman26]

A few points on the (in)effectiveness of 5.56 mm

This appears to be a more controversial subject than it needs to be. Based on the analysis of combat reports from the USA, UK, Germany, New Zealand, Australia and other ISAF units in Afghanistan and to a lesser extent previous experiences in Iraq, the following issues are accepted:

1. M855 5.56 mm NATO ammunition is most effective below 300 metres. Improved M855A1 EPR 5.56 mm ammunition is most effective below 500 metres. That's fine, because 5.56 mm was always designed to perform best below 500 metres. However, the theory that 90% of infantry engagements take place at ranges below 300 metres has now been debunked. UK data relating to Afghanistan states that more than 50% of combat engagements take place at ranges above 300 metres out to a maximum distance of 900 metres. This was true in Kosovo, the Falklands and several other Cold War era skirmishes.

2. It is true to say that most of the killing both with 7.62 mm and 5.56 mm ammunition is still done at ranges below 500 metres, but infantry small arms have another vital role to perform: suppression. Very often it is extremely difficult to pin-point an enemy position, therefore suppression is required to fix the enemy in place while other units manoeuvre into an assault position or supporting air assets or artillery fire is called in. 5.56 mm has a significantly reduced signature versus 7.62 mm (and 6.5 mm Grendel for that matter) so you must miss much closer to an enemy to have a suppressive effect.

3. M855 5.56 mm is highly susceptible to wind drift. On a range at sea level in lab conditions, it is entirely possible to hit a target at 600 metres - even 800 metres if you are a crack shot - but in the mountains of Afghanistan with a gale blowing it can be difficult to hit targets at 200 metres. It is a 4 MOA ammo.

4. M855 5.56 mm is highly susceptible to intermediate barriers that may obscure a target, such as car windscreens, wooden door frames, light masonry and thick foliage. The increasing use of body armour is also an issue.

5. In terms of terminal effectiveness, the yaw characteristics of 5.56 mm are dependent on striking velocity and angle of attack. The only way to increase terminal effectiveness is to ensure the projectile fragments. Soldiers have reported repeated instances of through-and-through shots that do not cause sufficient wounding to incapacitate.

6. Any unit equipped only with 5.56 mm weapons, will be overmatched by an enemy using full power weapons and ammunition. The Taliban has been using Russian-made PKMs and SVDs to engage ISAF units at ranges whether the latter cannot return fire. This happened time and again from 2006 and until 7.62 mm weapons were readopted at squad level.

All of these concerns should we well know to forum members here. They're reason why the US army developed the M855A1 EPR. Even though the the EPR is better, it still isn't a match for full-calibre ammunition 7.62 mm and above.

Personally, I tend to agree with Cory here. I think that 5.56 mm is useless in anything other than a PDW / SMG role. I'd love to see 6.5 Grendel adopted across the board - it would be a much better solution even though it cannot be a standalone round. The only issue I have about Grendel uppers slotted onto existing M4 weapons is that they restrict magazine capacity to 25 rounds. A slighter larger receiver and magazine well could allow wider magazines and a 30 round capacity.

The UK Royal Marines want either a new calibre or the wholesales return to 7.62 mm for their next generation weapons.

When it comes to the politics of adoption, it is the Special Forces community who are most driving innovation in calibers and weapons. They like weapons such as the HK417 but are well aware of the weight and recoil penalty it imposes. They frequently fire automatic bursts BTW. Offer them a new round and they'll certainly try it. The .300 Blackout is a prime example. When a new weapon system proves itself it soon achieves a wider currency.

[stanc]

The only issue I have about Grendel uppers slotted onto existing M4 weapons is that they restrict magazine capacity to 25 rounds. A slighter larger receiver and magazine well could allow wider magazines and a 30 round capacity.

With the current stainless steel magazines, capacity is a function of height, not width. Capacity could easily be increased to 30 rounds by making the magazine a bit taller, as was done with the 30-rd Barrett 6.8 SPC mag.

A wider mag well would only be necessary if it were desired to have a 6.5 P-Mag.

[stanc]

Any unit equipped only with 5.56 mm weapons, will be overmatched by an enemy using full power weapons and ammunition.

Sorta like this?

https://www.youtube.com/watch?v=rLHU-_OhT8g

[Michael]

6. Any unit equipped only with 5.56 mm weapons, will be overmatched by an enemy using full power weapons and ammunition. The Taliban has been using Russian-made PKMs and SVDs to engage ISAF units at ranges whether the latter cannot return fire. This happened time and again from 2006 and until 7.62 mm weapons were readopted at squad level.

I am not a ballistics expert but I can see the shortcomings in the 5.56 round. I do consider myself fairly knowable on the nation’s enemies/potential enemies – that’s part of my job. Which of our adversaries, or projected adversaries, are using 'full power' weapons? The preponderance of forces we will fight against/are projected to fight against are equipped with 7.62x39/5.54x39 AK style weapons. The 5.56 is comparable ballistic-wise to these weapons and superior when you talk accuracy beyond 100m. The short sight radius on the AK family, combined with the stamping manufacturing process don’t lead these weapons to be as accurate at the M-16 family at distances…but there are always exceptions . Yes, the 7.62x39 has better penetration, but by and large that advantage is outweighed by the poor max range (maxes out at less than 400m vs 500m for 5.56) and accuracy comparison. Even when you add optics to the AK, you still battle the manufacturing limitations.

7.62x54 is predominately a MMG/GPMG or sniper round. Our answer to that is the 7.62x51 as our MMG/GPMG and sniper round. (yes, I am excluding the .338 Lapua and HMG rounds in this comparison). While these are not necessarily found within the TO/E at the Squad level, they are in the TO/E at the Company/Battalion level. Utilizing/employing these weapons is a tactical decision based on the threat in any given situation.

Yes, there are some countries that still have .308/7.62x51 weapons as their primary battle rifle but they are not as prolific as the AK family among our adversaries or potential adversaries. Estonia, Turkey, Brazil to name a couple of nation states that use the 7.62x51 – but are they potential enemies? Yes, terrorist/criminal organizations may have these as well, but in what numbers? I saw NONE of these weapons employed against me or my units in Kosovo, Afghanistan or Iraq.

So again, WHO are these adversaries that are equipped with ‘full power’ weapons? I don’t know everything , but I am confused by what I see as a fairly flawed argument. What developments are underway in our potential adversaries’ gun-works that leads us to believe we will be overpowered in our next engagement? Again, the 5.56 is not a perfect round, but it has never failed me and I have never felt outgunned.

[Trooper]

I am not a ballistics expert but I can see the shortcomings in the 5.56 round. I do consider myself fairly knowable on the nation’s enemies/potential enemies – that’s part of my job. Which of our adversaries, or projected adversaries, are using 'full power' weapons? The preponderance of forces we will fight against/are projected to fight against are equipped with 7.62x39/5.54x39 AK style weapons. The 5.56 is comparable ballistic-wise to these weapons and superior when you talk accuracy beyond 100m. The short sight radius on the AK family, combined with the stamping manufacturing process don’t lead these weapons to be as accurate at the M-16 family at distances…but there are always exceptions . Yes, the 7.62x39 has better penetration, but by and large that advantage is outweighed by the poor max range (maxes out at less than 400m vs 500m for 5.56) and accuracy comparison. Even when you add optics to the AK, you still battle the manufacturing limitations.

7.62x54 is predominately a MMG/GPMG or sniper round. Our answer to that is the 7.62x51 as our MMG/GPMG and sniper round. (yes, I am excluding the .338 Lapua and HMG rounds in this comparison). While these are not necessarily found within the TO/E at the Squad level, they are in the TO/E at the Company/Battalion level. Utilizing/employing these weapons is a tactical decision based on the threat in any given situation.

Yes, there are some countries that still have .308/7.62x51 weapons as their primary battle rifle but they are not as prolific as the AK family among our adversaries or potential adversaries. Estonia, Turkey, Brazil to name a couple of nation states that use the 7.62x51 – but are they potential enemies? Yes, terrorist/criminal organizations may have these as well, but in what numbers? I saw NONE of these weapons employed against me or my units in Kosovo, Afghanistan or Iraq.

So again, WHO are these adversaries that are equipped with ‘full power’ weapons? I don’t know everything , but I am confused by what I see as a fairly flawed argument. What developments are underway in our potential adversaries’ gun-works that leads us to believe we will be overpowered in our next engagement? Again, the 5.56 is not a perfect round, but it has never failed me and I have never felt outgunned.

The AK family is either 7.62x39 or 5.45x39 of which is neither battle rifle caliber. Now the Afghanistani do like the old Enfield MkIII (.303) which we should make in .308 for the Afghan army
as it would be a better weapon/caliber for their area. Plus they are more familar with the Enfield MkIII and they tend to have to do longer range shots than we would in the US.

[Michael]

Trooper - sorry, my dyslexia kicked in on the AK-74 caliber. You're correct. But that was my point...who uses the battle rifle caliber? The 5.56 and M16 family are on par/more accurate than the opposition’s primary rifle.
Re the .303 Enfield’s…saw a few of those in Afghanistan especially with the older folks in the south. Great rifle, until you see the local’s ideas for cleaning them... we traded them some .30 cal bore brushes for ice and watched them run that brush up and down the bore. Probably lost a lot of accuracy over time with that technique.

I would classify a the MkIII bolt gun more into the sniper rifle category instead of a modern battle/assault rifle. WWII was an example of what happens when you pit infantry armed with bolt action rifles (Japanese and Germans) against infantry armed with a semi-auto (U.S.).

[LRRPF52]

The direction I see this conversation go a lot is based on geography of the Afghan AOR, which is somewhat unique in the world. When the 5.56 NATO was developed, it was done with Europe in mind, and is actually an excellent cartridge for the forests and urban areas on the European Steppe, for maneuverable and flexible units to sustain multiple contacts, engagements, and follow-on missions without constant re-supply of ammunition.

It also tends to go down the path of looking at dismounted infantry warfare in terms of the service rifle or carbine as being the dominant weapons in pursuing solutions to force-on-force engagements, where no enemy we have fought has chosen to meet us on our terms since the 1950's.

You also have to ask: "Does it make sense to adopt a universal caliber that is more ideal for Afghanistan, and make every RTO, Key Leader, Forward Observer, Assistant Gunner, Ammo Bearer, Anti-Armor Weapon Specialist, combat engineer, generator mechanic, driver, cook, supply sergeant, etc. carry that versus 5.56?"

[Trooper]

The direction I see this conversation go a lot is based on geography of the Afghan AOR, which is somewhat unique in the world. When the 5.56 NATO was developed, it was done with Europe in mind, and is actually an excellent cartridge for the forests and urban areas on the European Steppe, for maneuverable and flexible units to sustain multiple contacts, engagements, and follow-on missions without constant re-supply of ammunition.

It also tends to go down the path of looking at dismounted infantry warfare in terms of the service rifle or carbine as being the dominant weapons in pursuing solutions to force-on-force engagements, where no enemy we have fought has chosen to meet us on our terms since the 1950's.

You also have to ask: "Does it make sense to adopt a universal caliber that is more ideal for Afghanistan, and make every RTO, Key Leader, Forward Observer, Assistant Gunner, Ammo Bearer, Anti-Armor Weapon Specialist, combat engineer, generator mechanic, driver, cook, supply sergeant, etc. carry that versus 5.56?"

The Russians learned that the 5.45x39 did not cut it with the Chechnya conflict. The stone buildings of Europe make the .22 caliber rounds less effective. We are doing more urban warfare, not battles on open ground. Even if we did not have the long range shots of Afghanistan, just the battles in the villages of Iraq and most of the other Islamic countries would be forcing us to go to a larger caliber. Thus what the Russians, the Chinese and others are in the process of doing. We need a general purpose cartridge.

[stanc]

You also have to ask: "Does it make sense to adopt a universal caliber that is more ideal for Afghanistan, and make every RTO, Key Leader, Forward Observer, Assistant Gunner, Ammo Bearer, Anti-Armor Weapon Specialist, combat engineer, generator mechanic, driver, cook, supply sergeant, etc. carry that versus 5.56?"

It may or may not, depending upon:

a. Is it better to have a caliber that is excellent for, say, 90% of combat theatres, but inadequate for 10%, or a caliber that is excellent for 10%, and usable for the other 90%?

b. Is it better to have the simplified logistics of a single, universal caliber versus two or three specialized calibers?

c. Is the weight penalty of a universal caliber for Key Leaders, RTOs, FOs, etc, unacceptable or tolerable? (Use of the M14/M60, FAL/MAG, and G3/MG3 before adoption of 5.56x45 would seem to indicate that the weight of universal caliber weapons is tolerable.)

[Von Gruff]

Iluminating discussion.

[LRRPF52]

It may or may not, depending upon:

a. Is it better to have a caliber that is excellent for, say, 90% of combat theatres, but inadequate for 10%, or a caliber that is excellent for 10%, and usable for the other 90%?

b. Is it better to have the simplified logistics of a single, universal caliber versus two or three specialized calibers?

c. Is the weight penalty of a universal caliber for Key Leaders, RTOs, FOs, etc, unacceptable or tolerable? (Use of the M14/M60, FAL/MAG, and G3/MG3 before adoption of 5.56x45 would seem to indicate that the weight of universal caliber weapons is tolerable.)

a. Or is it better to have a caliber that only moderately improves effective range in one theater in the hands of the few who will actually be able to employ it (10% of the Army/Marines), while reducing combat endurance for them across the board in all theaters, and saddling all the soft skills with the same issues of increased recoil, reduced ammunition capacity per weight? Would the reduced machine gun ammo weight and increased mobility for gunners balance out the combat endurance?

b. For logistics sake only, it makes a lot of sense, but we still will have multiple application cartridge loadings, even within the same packaging and issuing containers: Tracer/ball linked for belt-feds, rifle loads on stripper clips, DM/SASS load in 20rd boxes, all in their own DODAC-mandated ammo cans.

c. With the 7.62 NATO system, SMG's and older era carbines were predominant in the hands of key leaders and non riflemen personnel, not only in the US, but in the European nations and their former colonies. The Bundeswehr with the Uzi and MP5, the Italians with the Beretta SMG, the Sten with the UK, the M1 Carbine with the US (Army Special Forces held onto the M1 and M2 Carbines up until they received the AR15, and the 82nd + Airmobile units couldn't ditch the M14 fast enough.) Even the non-NATO Finns kept using the M44 9mm SMG for their Airborne forces after adopting the Valmet Rk62 7.62x39 AK variant.

On top of that, the M14/M60 universal caliber system was a terrible failure operationally in Vietnam, due to limited combat endurance and a drag on the logistics system to re-supply units constantly after very limited contact.

I will say that the 7.62x39 universal system for light infantry units worked very well in SEA and Africa, with the Chicom Type 56 AK and RPD combo, however that isn't used in an area like Afghanistan due to the open spaces and increased distances, where the AKM copies and PKM + SVD are used together.

The Russians have had great success with the 5.45x39 assault rifle + PKM and SVD in 7.62x54R, while the Chinese have not with the 5.8x42 universal system, which leaves much to be desired at extended distances and mandates slightly larger magazines for the already diminutive chests of Sino soldiers. They still don't have a universal caliber anyway, because they have a 5.8x21 PDW cartridge. The moment you try to go one-size fits all, a lot of feet will be wearing different boots, even with the centrally-planned Chinese and Russians.



In that light, we might even consider getting rid of 5.56 NATO and 7.62 NATO and do a PDW based off the 6x.221 Fireball for riflemen (KAC 6x35 PDW), the high-powered Grendel for DM's and LMG's, and some .338 Long-Range weapons to replace the .50 BMG. You can carry a ton of rounds with the 6x35, since the cartridges are shorter, while not losing a lot of effective range for practical engagement distances.

Run a mix in the armory at the unit level so Joint Rapid-Deployment Units could tailor their weapons mix for the AOR and mission profiles assigned to them. Examples: CENTCOM Afghanistan would have a heavy mix of 6.5 Grendel for at least half of the soldiers normally carrying carbines/rifles, while key leaders, RTO's, etc. could carry a very lightweight carbine in 6x35, with 1.5x + the 5.56 basic load for the same weight.

If heading to Mali, the Philippines, or the Caribbean Region, a unit would end up leaning on a heavier lightweight carbine mix, with Grendel DMR's and LMG's in the usual supportive roles.

With a 14.5" barrel, enhanced bolt & extension, and the right load, I think the 6x35 could actually beat the 5.56, as a neighbor of mine gets 3,800fps with a 55gr projectile from his .221 Fireball. The KAC 6x35 PDW was built with 8" and 10" barrels in mind, and is still assault-rifle effective out to 300m in current form. By going to the 6mm, we can reduce barrel weight, open up our projectile configuration options a little, and still run a 65gr General Purpose projectile at 5.56 speeds from equivalent barrels.

Imagine the endurance of a unit that has riflemen/assaulters with 300rd basic loads, with Multi-Role LMG gunners able to carry more than a 7.62 GPMG in less space/weight, with DM's and Snipers carrying lighter, more wind-bucking, less-recoiling blasters, with the Grendel and .338 LM systems, ditching 7.62 NATO, .300 Win Mag, and .50 BMG.

When the discussion encompasses all the systems we really carry, anyone realizes straight away that any illusions of a universal caliber are quite narrow in scope.

[Michael]

It may or may not, depending upon:

a. Is it better to have a caliber that is excellent for, say, 90% of combat theatres, but inadequate for 10%, or a caliber that is excellent for 10%, and usable for the other 90%?

b. Is it better to have the simplified logistics of a single, universal caliber versus two or three specialized calibers?

c. Is the weight penalty of a universal caliber for Key Leaders, RTOs, FOs, etc, unacceptable or tolerable? (Use of the M14/M60, FAL/MAG, and G3/MG3 before adoption of 5.56x45 would seem to indicate that the weight of universal caliber weapons is tolerable.)

[Trooper]

PDW vs. AR

It may or may not, depending upon:

a. Is it better to have a caliber that is excellent for, say, 90% of combat theatres, but inadequate for 10%, or a caliber that is excellent for 10%, and usable for the other 90%?

b. Is it better to have the simplified logistics of a single, universal caliber versus two or three specialized calibers?

c. Is the weight penalty of a universal caliber for Key Leaders, RTOs, FOs, etc, unacceptable or tolerable? (Use of the M14/M60, FAL/MAG, and G3/MG3 before adoption of 5.56x45 would seem to indicate that the weight of universal caliber weapons is tolerable.)

If you consider that the pistol is seen as a PDW then a more robust PDW like the FN P90 (5.7x28) or the HK MP7 (4.6x33) might be of interest. Inside the wire (on a FOB or in garrison here in the states) a PDW makes sense. I do not want to have be dragging a larger rifle around. But outside the wire in a combat arena, I want general purpose rifle (GPR). The problem is that as a GPR, the M4 (5.56x45) is too light and the M14/M110 (7.62x51) is too heavy. A GPR using a 6.5mm round makes more sense.

What you have suggested, which has been a topic of discussion within NATO, is whether we need a PDW that is more effective than are our current 9mm pistols (M9/M11). While the M4 does a personal defense mission, for many of our troops a smaller PDW might be wise.