Optimized Caliber

[BluntForceTrauma]

Thanks, Tony, it's always good to read your thorough analyses. Your articles have been very influential in my thinking.

[LRRPF52]

I just ran a series of data on how an Infantry Rifle Squad fare's with regards to combat endurance and follow-on mission capability after a chance contact while patrolling in the vicinity of a village.

With the successful execution of Battle Drill 1.a (Squad Attack), and NO casualties, the Infantry Squad is at 81% combat readiness after the quick pursuit of an enemy harassment team. 1-3 mags per soldier w/5.56 carbine were expended, with 100rds of linked per SAW, as well as 3x40mm HE per Grenadier.

They could endure one more engagement of this impact on their ammunition status, after which they would be 60% ready.

If I ran the sequence with Grendel, you need 2lbs more carrying capacity per Rifleman, Grenadier, Team Leader, and Squad Leader, for one less magazine. Not sure how much weight increase the SAW gunners would see.

8x30rd 5.56 NATO loaded aluminum mags = 8.47 lbs/240rds
7x30rd Polymer Grendel loaded mags = 10.5 lbs/210rds

You will never have the same bounds of fire & maneuver per weight with anything using projectiles that are significantly heavier than 5.56 NATO, so you have to convince Big Army that the increased strain on the logistics posture is really worth it in the long run, as re-supply operations slow down the pace of taking ground, while increasing combat arms AND combat support units, to include unit internal re-supply assets (Platoon Sergeant w/Medic, or 1SG w/driver, another Squad that could be combat-focused, etc.).

[Tony Williams]

What does that tell us? That a Grendel round weighs more than a 5.56mm. Yep, knew that already. Using that assessment, the troops would have even more combat endurance if they were equipped with 5.7mm P90s or 4.6mm MP7s (all we need is a dinky little belt-fed MG to fire them).

Ammo weight is just one of the many considerations driving weapon and ammunition choices. By willingly carrying 7.62mm weapons instead of 5.56mm, the troops in Afghanistan have demonstrated that range and lethality can override weight in their priority order.

[LR1955]

By willingly carrying 7.62mm weapons instead of 5.56mm, the troops in Afghanistan have demonstrated that range and lethality can override weight in their priority order.

Tony:

Joes tend to believe anything bigger must be better. Few if any have the skills to prove it. They see a bigger cartridge like a round of M-80 and think it is more effective than their round of 5.56.

What conventional forces have the option of carrying a 7.62 rifle over their issued M-4? I know there are EBRs and M-110's out there but they are not for general issue.

Please link us to a study that proves in quantitative (not qualitative) terms that hit and kill ratios in Afghanistan were significantly higher at distances from 300 to 600 meters because someone had a issued 7.62 carbine firing issued M-80 Ball as opposed to a 5.56 carbine firing issued M-855. And that the same study quantitatively proves that range overrides lethality and that range and lethality, range only, or lethality only override weight.

Just because someone carries a specific anything that is different from standard issue doesn't mean it is better.

LR1955

[LRRPF52]

Ammo weight is just one of the many considerations driving weapon and ammunition choices. By willingly carrying 7.62mm weapons instead of 5.56mm, the troops in Afghanistan have demonstrated that range and lethality can override weight in their priority order.

They are issued a small arms structure that is a mix of mostly 5.56 carbines, with very few 7.62 DMR's. Nobody that I know of is carrying 7.62 NATO universally across their small arms mix, although the Norwegians did earlier in the campaign with the AG-3 before they adopted the HK416.

By this, we know that US/UK and other professional armies are not only willing, but in fact are employing a 2-caliber small arms mix at the Squad-level, when it used to be 5.56 NATO universal for at least a US Infantry Squad with M16 family and the SAW.

I still think a universal caliber at the Squad-level is doable with the Grendel, but not necessary, and I would still want an assault rifle load, versus the LMG load, which takes us back to our cost-benefit analysis to 5.56 NATO/MRLMG Grendel structure.

You are absolutely right about factoring in the performance capability of the cartridge/weapon system in relation to weight, and do we favor in the direction of:

* lightweight, higher mobility, longer combat endurance....or
* more weight, less mobility, less combat endurance, but higher-power ammunition

The current 5.56 NATO service weapon/7.62 DMR mix satisfies both of those considerations, without significantly reducing the unit's ability to make contact, fight through the contact, and be prepared for 2 more contact sequences before needing a re-supply.

The Grendel would reduce the weight of the 7.62 DMR, while increasing mag capacity and combat endurance of the Squad, and still allow the DMR's to perform as rifleman-assaulters within close quarters.

[Tony Williams]

When it comes to ammunition weight, I suspect that belt-fed MGs are more significant than rifles. I recall hearing a US Army presentation a couple of years ago about the introduction of the MK48 7.62mm LMG. At that time, the dismounted troops were carrying both 5.56mm M249 and 7.62mm M240. The Army expected the troops to leave the M240 back at the base and take the MK48 instead - but they found that it was the M249 which was being left behind in favour of a MK48 and M240 combination.

Basically, the troops were happy to rely on 5.56mm in the short ranges of Iraq, but when they got to the longer ranges in Afghanistan, they were delighted to get hold of 7.62mm MGs and rifles (even bolt-action rifles initially in the BA, for want of anything better). They found the 5.56mm weapons ineffective at longer ranges, while the 7.62mms did what they wanted. By far the most popular small arms in the BA sections are the 7.62mm GPMG and L129A1 Sharpshooter rifle. Even the BA's senior officers concerned with small arms regard the 5.56mm as having an effective range of only 300m (the emphasis being on effective - I am aware it can perform better than this on the target range).

You may say that this is all in the mind but I doubt that, on the basis of some of the first-hand reports I've heard. Even if it is, I wouldn't dismiss too quickly a factor which has such a powerful effect on combat morale.

[LRRPF52]

Roger that Tony. 5.56 carbines and rifles are limited in effective range in the hands of Joe tentpeg. This is why it makes even more sense for a Grendel LMG, DMR, and SASS family of calibers/weapons, to cover the longer distances for dismounts. The 5.56 NATO LMG concept never really made a lot of sense to anyone.

One aspect that would make the Grendel LMG less of a pig is a lower cyclic rate, in conjunction with a constant-recoil system that allows faster on-target results for even an entry-level soldier with minimal training.

With Grendel LMG's DMR's, and SASS rifles built around the cartridge, we wouldn't be limited by the 50k psi bolt thrust capacity of the current AR15, so a 130gr load would do really well from all those weapons. The Mk46 and Mk48 could be transitional platforms for the caliber change, with a feed tray cover, feed tray, and barrel swap.

[JASmith]

... - but they found that it was the M249 which was being left behind in favour of a MK48 and M240 combination....

You may say that this is all in the mind but I doubt that, on the basis of some of the first-hand reports I've heard. Even if it is, I wouldn't dismiss too quickly a factor which has such a powerful effect on combat morale.

Would the decisions be the same if one or both of the MK48 and M240 were chambered for the Grendel?

It is said that morale is a weapon in its own right. The last thing one wants is a soldier who feels his weapon is useless. At the extremes, that can happen with ineffective ammo or heavy ammo that doesn't allow enough rounds to be carried. It is probably why we don't see many .50 BMGs used in this role.

One thing is true -- the Grendel round is lighter than the 7.62 NATO. Also, as you know, many of us argue that the other side either won't see the difference in effectiveness or the improved ability to hit with the Grendel will make him less comfortable. That would be a good thing...

[Tony Williams]

The 5.56 NATO LMG concept never really made a lot of sense to anyone.

The BA didn't have one before Iraq - they had an IAR instead (L86 LSW). As a result of the close-range fighting in Iraq they decided they needed the ability to put down a higher volume of fire, so they bought the Minimi in short-barrelled Para form with a telescoping stock. Opinions as to its effective range vary between 200 and 300 metres...

[LRRPF52]

I recall reading about what an abortion the L86LSW was when I was a kid in the 1980's. I carried the M249E2, and Para-SAW quite a bit myself. I would say that M855 is effective out to 200-300m in the hands of most soldiers. With optics and experience, that can be extended to 500m, but a 62gr pill isn't ideal really past 300m.

The 77gr Mk262 in the hands of a well-trained shooter can be reasonably effective out to 650m from a free-floated gun with decent optics.

The SAW's biggest problem is that it is way too bulky & heavy for what it is, and it isn't reliable, being based on the AK piston, bolt carrier, and bolt in a short sheet steel receiver that beats itself apart like an AK. The SAW can become a liability really quick. They did a PIP (Product-Improved Program) on it, supposedly reenforcing the receiver, along with the external addition of a telestock. The US & UK could put pressure on each other to fix this problem, because FN really dropped the ball when they made the Minimi.

From my viewpoint, a Squad-Level LMG needs to push a 130gr high-SD projectile at a decent velocity, so that it is effective out to 800m on point targets with optics, and really shines from 300-600m. With such a weapon, I would never need an attached GPMG team with a 7.62 belt-fed pig.

[Tony Williams]

The L86A1 had various problems, but it went through HK's magic repair shop and is now a decent weapon. It is very accurate and the long barrel means it can squeeze all there is to get from the 5.56mm cartridge. It's still shorter than an M16.

[LRRPF52]

The L86A1 had various problems, but it went through HK's magic repair shop and is now a decent weapon. It is very accurate and the long barrel means it can squeeze all there is to get from the 5.56mm cartridge. It's still shorter than an M16.

There's no way you can have a viable LSW that is 30rd mag-fed, and especially not one that prevents you from elevating while in the prone because of the mag.



With a 20rd mag chambered in Grendel, it could make a nice SASS platform if the barrel is floated, as it appears to be at least in the fore-end area on the L86A2. The trigger link would need to be modeled after the DSR-1 to be light, but they are finicky to field conditions and need tuning & lots of TLC.

There's not much worse than a dead trigger, or firing without the trigger being pulled.

[Tony Williams]

There's no way you can have a viable LSW that is 30rd mag-fed

Tell that to the Marines

[LRRPF52]

Tell that to the Marines

They've told it to me...if you mean Royal Marines. If you mean USMC, don't get me started again. We have another book-long thread on "USMC Adopts new IAR" The feeling is the same from Marines who have deployed with both IAR and SAW. They preferred the SAW for firepower...imagine that.

[LRRPF52]

Check this out:

Rockin' the Mk46 & 240. Most guys can't handle a 240 like that, just FYI. It really takes a man to run that pig.