Assault rifles and their ammunition

[Tony Williams]

I've just completely revised my web article on the past, present and future of assault rifles and their ammunition: http://www.quarry.nildram.co.uk/Assault.htm

[montana]

This proves my argument. Enjoyed it very much. Thanks for posting it.

[Whelenon]

Thanks for the article, that will be a little light reading before bedtime. Interesting.

[txgunner00]

Cool stuff.

I like the energy graph comparing .308,6.5g,6.8 & .556.

[LRRPF52]

Interesting read. One thing that might be cool to post is a graph depicting the dismounted infantry unit's ability to sustain a fight through a number of contacts-maneuvers, in a an ammunition-to-weight ratio. Specifically:

7.62x51 NATO battle rifle with "X" kg of ammo = 1 initial contact at "X" rpm per soldier, 1 window for maneuver, and one final contact/base of fire, whence ammunition has reached a critically low limit of "X" mags per soldier.

5.56 NATO assault rifle with same kg of ammo = 1 initial contact at same rpm per soldier, 1st maneuver, 2nd base of fire, 2nd maneuver, 3rd base of fire, maneuver, critically low limit reached.

6.5 Grendel Assault rifle with same kg of ammo = 1 initial contact at same rpm per soldier, 1st maneuver, 2nd base of fire, 2nd maneuver, 3rd base of fire, critically low limit reached.

And so forth. You can do it assuming that your SAW gunners have "Y" amount of ammo, able to sustain fire at 200rpm, with a SAW gunner load of 800rds of 5.56, or for a 7.62 weapon, the equivalent weight on his kit. Extra ammo is humped by the team and squad, or in an assault pack that needs to be accessed in a lull, if/when possible.

You could also account for DMR's firing at a much lower rate of fire, and the ammo they carry, if same as assault rifle, with the ability to distribute their load during moments of consolidation and reorganization.

All rates of fire for riflemen in the US system are absolutely on SEMI only, never AUTO. I have learned more and more that this practice is quite rare among foreign militaries, having worked with many of them first-hand.

[usmc1371]

sounds like we need tactical nuke bullets for the bad guys....

[usmc1371]

in desert storm i carried a dz mags for my rifle and i still didnt have enough ammo.......

[Tony Williams]

Interesting read. One thing that might be cool to post is a graph depicting the dismounted infantry unit's ability to sustain a fight through a number of contacts-maneuvers, in a an ammunition-to-weight ratio.

That would indeed be interesting, but I'm not the person to do it - I have no military experience.

[LR1955]

in desert storm i carried a dz mags for my rifle and i still didnt have enough ammo.......

Did you ever run out of your basic load while in a fight and if so, were you able to get more immediately or did your squad / platoon also run out so you could not get a single round?

LR1955

[stanc]

Interesting read. One thing that might be cool to post is a graph depicting the dismounted infantry unit's ability to sustain a fight through a number of contacts-maneuvers, in a an ammunition-to-weight ratio.

The closest I have seen to that is the comparison on p. 29 in:

http://www.dtic.mil/ndia/2007smallarms/5...g_12pm.pdf

[LRRPF52]

The closest I have seen to that is the comparison on p. 29 in:

http://www.dtic.mil/ndia/2007smallarms/5...g_12pm.pdf

Good find/reference. The moment you go from combat asset to liability is when you run out of the ammunition required to continue the fight forward, and now require another unit or vehicle asset to resupply you, placing drain on the focus from offensive to defensive.

[Variable]

Yikes, that chart on p. 29 seems to make a pretty good argument for the 5.56 cartridge. If you figure the Grendel weight as similar to a 7.62x39 round then you are only buying another 30 seconds over the 7.62 NATO, whereas the 5.56 buys you 3.5 minutes....

Too bad the 5.7 round isn't available with base bleed technology and a micro nuclear payload. I'd be real happy with a P90 if it did.LOL

[Tony Williams]

Yikes, that chart on p. 29 seems to make a pretty good argument for the 5.56 cartridge. If you figure the Grendel weight as similar to a 7.62x39 round then you are only buying another 30 seconds over the 7.62 NATO, whereas the 5.56 buys you 3.5 minutes....

Well, we all know that 7.62mm ammo weighs twice as much as 5.56mm, and that the guns are generally heavier too. No news there.

The problem with this comparison is that it assumes that 5.56mm and 7.62mm are equally effective, when there is clear that they are not - in terms of neither suppression nor range (leaving terminal effectiveness out of it). Why else would dismounted and already overloaded troops in Afghanistan be happy to carry the great lump of the GPMG/M240 and its heavyweight ammo? Because it gets the job done when 5.56mm can't.

[stanc]

Yikes, that chart on p. 29 seems to make a pretty good argument for the 5.56 cartridge. If you figure the Grendel weight as similar to a 7.62x39 round then you are only buying another 30 seconds over the 7.62 NATO...

Hmm. Considering the weight difference between 7.62x39 and 7.62x51, that just can't be right. I checked the numbers on that chart, and got significantly different results.

Their numbers:

182 - 7.62 NATO
385 - 5.56 NATO
210 - 7.62x39 (6.5 G w/123gr bullet)

My numbers:

178 - 7.62 NATO (M80 -- 392gr/rd)*
368 - 5.56 NATO (M855 - 190gr/rd)*
260 - 6.5 Grendel w/123gr bullet (268gr/rd)
274 - 6.5 Grendel w/110gr bullet (255gr/rd)

Going by their time figures (which also look to be off by about 25%), it gives:

7.62 NATO -------- 3.0 min
5.56 NATO -------- 6.1 min
7.62x39/6.5 G 123 - 4.3 min
6.5 G 110 --------- 4.6 min

Advantage is still to 5.56 NATO, but not quite as overwhelming.

* Weight data from TM43-0001-27

[LRRPF52]

Well, we all know that 7.62mm ammo weighs twice as much as 5.56mm, and that the guns are generally heavier too. No news there.

The problem with this comparison is that it assumes that 5.56mm and 7.62mm are equally effective, when there is clear that they are not - in terms of neither suppression nor range (leaving terminal effectiveness out of it). Why else would dismounted and already overloaded troops in Afghanistan be happy to carry the great lump of the GPMG/M240 and its heavyweight ammo? Because it gets the job done when 5.56mm can't.

5.56 & 7.62 NATO are about as equally ineffective if we're talking about soldiers just returning fire upon contact, since it is rare that guys connect. The 7.62 does have a bit of an advantage as far as its convincing power to keep your head down, but within typical engagement distances, I'd much rather get hit with a 7.62 than a 5.56. In 7.62's defense, it punches through barriers very well, but longevity of your fighting load will be a huge determining factor, if not the biggest factor-combined with marksmanship & small unit tactics if small arms are the only tools in play.

Even in semi-auto, it is extremely difficult for most soldiers to control the 7.62 NATO, so follow-up shots are unlikely. Can a seasoned veteran manage one better than most first-term soldiers can run an M4? Yes, but then we get into the training issue, and we'll never solve that without complete institutional overhaul. Then you look at guys that weigh 150lbs soaking wet, and they aren't humping a 7.62 battle rifle plus its basic load for very long at all. You also look at magazine capacity/prone considerations, and a 7.62 NATO rifle for a standard service rifle stays where it belongs...a footnote in history.

In a GPMG that fills a role of reaching out to 800m+ or providing local support by fire, 7.62 NATO makes sense has done a fairly good job of it, weight penalties and lack of maneuverability aside. The Mk48 is attractive in this regard since it is more maneuverable and much lighter, but now we're talking machineguns again.

It's interesting that the MARS and 6x35 KAC PDW are mentioned in that article, because that caliber would do just as well as 5.56 in close-range engagements, although it lacks the terminal ballistics of 5.56 unless expanding tip projectiles are used. I wonder if a propellant could be developed to get it to match 5.56 velocities out of a 16" barrel, because I could carry 20-24 mags of that and be totally fine. It has the ability to lighten up a soldier's load, while reducing space taken on his kit. If the hybrid polymer/metal cases could take the pressures, weight could be significantly reduced.

We want a lot out of technology, and we're at the edge of capability and performance with 5.56 NATO, which is an awesome cartridge for its size/weight, that will be difficult to exceed considerably. We want .50 BMG API or Roufouss terminal performance, with .22 LR recoil and ammo weight.

[stanc]

It's interesting that the MARS and 6x35 KAC PDW are mentioned in that article, because that caliber would do just as well as 5.56 in close-range engagements, although it lacks the terminal ballistics of 5.56 unless expanding tip projectiles are used. I wonder if a propellant could be developed to get it to match 5.56 velocities out of a 16" barrel, because I could carry 20-24 mags of that and be totally fine.

IMO, the 6x35 is too short range for a general purpose, combat rifle cartridge.

I think a better option is to neck up the 5.45x39 case to take a long, high-BC, .243" projectile, and blow out the shoulder to increase powder capacity.

Such a 6mm "Mini-Grendel" might give muzzle velocity close to that of 5.56 M855, with higher downrange velocities and better terminal effects. And do it with little negative impact on ammo weight or magazine capacity.

[Tony Williams]

Even in semi-auto, it is extremely difficult for most soldiers to control the 7.62 NATO, so follow-up shots are unlikely. Can a seasoned veteran manage one better than most first-term soldiers can run an M4? Yes, but then we get into the training issue, and we'll never solve that without complete institutional overhaul. Then you look at guys that weigh 150lbs soaking wet, and they aren't humping a 7.62 battle rifle plus its basic load for very long at all. You also look at magazine capacity/prone considerations, and a 7.62 NATO rifle for a standard service rifle stays where it belongs...a footnote in history where it belongs.

You make a good case that 7.62mm is too big and heavy and recoils too much, and there seems to be general agreement about that.

However, there is also general agreement that 5.56mm is a 400m cartridge at best, in rifles or MGs, and runs out of effectiveness pretty rapidly after that. Which is why the Taleban so often attack from longer ranges than that. The PEO Soldier document on effectiveness stressed the importance of general-purpose rifles and ammunition, suited to engaging the enemy at any distance from which he can attack.

We want a lot out of technology, and we're at the edge of capability and performance with 5.56 NATO, which is an awesome cartridge for its size/weight, that will be difficult to exceed considerably. We want .50 BMG API or Roufouss terminal performance, with .22 LR recoil and ammo weight.

Yes that would be great! However, as we know, it is entirely possible to match the 7.62 M80's long-range performance with a significantly lighter, more compact, and lighter-recoiling cartridge.

[LRRPF52]

You make a good case that 7.62mm is too big and heavy and recoils too much, and there seems to be general agreement about that.

However, there is also general agreement that 5.56mm is a 400m cartridge at best, in rifles or MGs, and runs out of effectiveness pretty rapidly after that. Which is why the Taleban so often attack from longer ranges than that. The PEO Soldier document on effectiveness stressed the importance of general-purpose rifles and ammunition, suited to engaging the enemy at any distance from which he can attack.



Yes that would be great! However, as we know, it is entirely possible to match the 7.62 M80's long-range performance with a significantly lighter, more compact, and lighter-recoiling cartridge.

For the type of terrain and general lay of the land in Afghanistan, the Grendel makes a ton of sense for DMR's, Spotters, and LMG's. It makes a lot of sense for LMG's anywhere. The Taliban prefers to initiate contact out of all small arms range, especially with 12.7mm & 14.7mm weapons, in conjunction with RPG's. No shoulder-fired small arms appropriate for a rifleman address that threat. For a rifleman, a 400m capable carbine is plenty fine, balanced with the more common demand for him to deal with close-in targets in tight confines, whether they be a bunker or trench complex, or an urbanized or rural farm community.

I think we're at a point where projectile, propellant, and cartridge or energy-harnessing technology needs to take a step forward, since we have some pretty stretched systems given the current state of metallic cartridges. The Grendel is a tweak of that existing technology that offers a lot of bang for its weight for an intermediate range weapon, just like the 5.56 offers a lot of bang for its weight in the 0-300m realm.

[Tony Williams]

Don't forget, though that new sights like the DInGO will be along soon. This combines red dot with imaging-enhancing video with 16x zoom magnification, a laser rangefinder, ballistic computer and corrections for uphill, downhill and weapon cant. The weight target is less than 350g (12.3oz - plus 3x AA batteries) and the cost less than $1000. It's expected to be ready for field testing this summer and to be ready for service within 1-3 years.

This will dramatically improve the potential for accurate long-range fire by ordinary riflemen - provided that the gun and ammo are up to it.

[LRRPF52]

LOCKHEED MARTIN TO DESIGN NEW RIFLE SIGHT TO HELP EVERY SOLDIER BE A MARKSMAN: Military optical sensor experts at the Lockheed Martin Mission Systems & Sensors segment in Akron, OH, are developing an experimental advanced rifle sight that helps every soldier be a marksman by enhancing the ability to hit targets at ranges from 3 to 2,000 feet. Lockheed Martin won a $3.9 million contract last week for the Dynamic Image Gunsight Optic (DInGO) program to develop an optical scope attachment for standard combat rifles like the M16 and M4 with field-of-view and angular magnification that can be automatically reconfigured and optimized based on the range to target.
Awarding the DInGO contract is the U.S. Space and Naval Warfare Systems Command in San Diego, on behalf of the U.S. Defense Advanced Research Projects Agency. Lockheed Martin optical systems integrators are being asked to produce a prototype rifle sight with rapid, seamless, automated, or hands-free actuation to enable soldiers to keep both hands on their weapons as they use the rifle sight. The scope must allow for a wide field of view for close quarters battle, as well as sufficient magnification and resolution to hit moving targets farther than a quarter mile away. Lockheed Martin designers will compensate for bullet drop and moderate winds to enhance marksman accuracy at long ranges. The optical resolution of the DInGO prototype will be sufficient to enable the user to recognize targets at ranges as far away as 1,000 feet between dawn and dusk. The DInGO rifle sights will operate for as long as eight hours continuous operation - or seven-day limited operation - with two AA batteries. Ultimately, SPAWAR is asking Lockheed Martin to develop a rifle sight that costs less than $600 in quantities of 50,000. (Military & Aerospace Electronics, 05/09)

In other words, they have asked for it to function and perform its tasks without the soldier removing his hands from the weapon, to be viable in a CQB-to-further than 400m range on moving targets, compensate for bullet drop and moderate winds, with an 8hr battery life for a price of $600 per unit per 50,000 unit order.

They seem to correlate 400m with long range, which it isn't. If they can pull this off, keep the unit small and lightweight, like under 16oz., and integrate all those capabilities, they still will need a soldier who can hold the weapon steady enough to make the hits, and an 8hr battery life won't cut the mustard, I can assure.

There are a lot of tall orders in that stack, even with a 400m capable system. The price is almost laughable, even with the volume ordering. That's the price of an Eotech or Aimpoint, and this unit will have integrated LRF, BDC, Wind Compensation, variable magnification, and some type of limited visibility capability in hours of dawn/dusk? Can't wait to see it...

Prediction (and I honestly hope I'm wrong): The taxpayers are in for another fleecing on this one, while Lockheed Martin will profit from millions in R&D. Look for them to say that significant obstacles in integrating the technology have been encountered, if the weight and cost objectives continue to be non-negotiable, and they need more money if the program is to continue. The next beg will be for 3-10x the initial R&D budget. This all might be good for the actual ground taken towards such a sight, but I am doubtful at best that the will pull it off.