This discussion started in the comments section of the previous post, but I’ll break it out here. I’ve mentioned this stuff before in various places (as have others) but here it is in one place.

The recent Sources Sought Notices for infantry weapons require a light machine gun (LMG) variant to replace the M249 squad automatic weapon (SAW).

I think there’s a place for both the 5.56 SAW and the 7.62 LMG (though, as always, maybe a 6.8 compromise would work). The lesser stopping power of the 5.56 isn’t such a liability in the SAW role, as it’s mostly setting base of fire and holding bad guys in place, so the “more ammo” argument carries a lot more weight (so to speak) with a SAW than it does with an assault rifle.

But there also needs to be a heavier LMG to do the dirty work.

Even if the new assault rifle goes to 6.8 (which it almost certainly won’t) I think there’s a strong argument to keep the SAW a 5.56. However, I don’t think any 5.56 LMG will replace the M60/M240 role. At least not effectively.

I know that the military would like to have a family of mostly-compatible weapons for the infantry, but compromises mean giving up things. I don’t think giving up too much is too good for the troops on the ground.

We might be best off with a a 6.8mm modular assault rifle with short, medium, and long barrels, a separate 5.56mm SAW, and a separate 7.62mm LMG. If the assault rifle is going to be 5.56mm (as seems likely) then the SAW could be part of that family as long as it has quick-change barrels and heavier construction.

Trying to shoehorn every role into one weapons systems might sound good in theory, but it runs the real risk of giving no one what they need to do their job.


  1. I think the military blew it with the new assault rifle. This was THE chance to lead the way by going with something built around a telescoped caseless round, and they stuck with brass. As we’re going to be using cased ammo for a long time, I’d have to run with the 5.56. The more calibers you have in the logistics pipeline, the harder it is to supply the troops with what they need when they need it.

  2. Didn’t we argue this once before? Telescoped caseless rounds are more expensive, and if you do have the round, you need to devise the weapon to fire them, and one of the big benefits to caseless is the ability to remove the ejection port, ejector, and extractor. Problem is, when the weapon jams (and it will, double feed or ‘stovepipe’ round) there’s no good way to get into the mechanism to remove the jam. You have to build rough and ready to take the abuse of the ‘lowest common denominator’ be that environmental conditions, someone that’s not familiar with firearms before they joined the service, or someone that’s just not terribly bright. It needs to be easy, and cased cartridges are the easiest. I know what you mean though, I was hoping for ‘real breakthrough’ stuff, myself. But, back to the thread. Maybe we could go to 6.5 grendel for both, as that has good destructive power (heavier bullet, high velocity, good BC) but if not we should still have the LMG role fulfilled with a 7.62x51mm design. The M-60 rocked, everybody around hit the dirt when that pig opened up. The SAW concept could be fulfilled by a 5.56mm weapon, but I’d like to see it go to 7.62, as the hitting power and range go way up.

  3. I heard from a few ‘Quiet Professionals’ that, when using the right ammunition, 5.56 mm is rather effective at killing BG’s. These same guys are also very confident in the 5.56 LeMas rounds. Personally, I’d like to see a 6.5 mm Grendel round coupled the LeMas’ Blended Metal Technology (BMT). Any thoughts? -Justin

  4. I heard from a few ‘Quiet Professionals’ that, when using the right ammunition, 5.56 mm is rather effective at killing BG’s. These same guys are also very confident in the 5.56 LeMas rounds. Personally, I’d like to see a 6.5 mm Grendel round coupled the LeMas’ Blended Metal Technology (BMT). Any thoughts? -Justin

  5. Chad: The point of a caseless roudns isn’t to remove the ejection port, any weapon must have an ejection port, how else would you remove a round you chambered but do nto wish to fire. The only [WORKING] caseless rifle to have been made, the H&K G11 still had a sort of ‘ejection port’… I can’t explain it so just look up the G11’s design. The point of a caseless round is so you don’t have to eject anything in normal firing, ejecting the old round, and the process that it involves are what takes the most time in the reloading cycle when you consider that if you didn’t need to eject a spend case, you wouldn’t need the traditional forward-backward movement of the weapons action. If you don’t need to eject a round, it is as simple as opening the chamber [Which is now as simple as opening a ‘hatch’, not the huge bolt movements in rifles today] and stuffing a new round in. This allows a MUCH higher rate of fire and gives you one less thing that could go wrong [failure to eject, a big issue, as you may know, in the M16]. On the G11 the rifle could fire at 2,000 rounds a minute [and in my opion, H&K wasn’t pushing it to the limit], this allowed a three round burst to be fired before any of the recoil was felt by the shooter, and therefore all three bullets follow almost the same path. This means any person or thing you hit will be hit by 3 rounds in about a 2′ group at almost the same time. The G11 could also fire in full auto at this rate, but H&K decided to cool it down a bit for full auto because of recoil and muzzle rise. Also caseless rounds save weight [no case… kinda speaks for itself] and tend to burn better than cased rounds. The only real gripe I have about the G11 was the bullet itself… 4.6mm [.185 cal] and 33 grains [not 100% sure on the weight]… Needs to be a bit more powerful. I’m not saying we should go with caseless… anything but at this point, but there are advantages, and it is a field ready system.

  6. Out of interest, if the caseless ammo is kept in a manner similar to that in the field, ie. wading through a swamp/dirty water. Would the bullet not burn and thus, due to residue left behind by the bullet being coated in dirty water, leave heavily burnt on dirt on the chamber walls? The problem with this being that while the build up of dirt may be slow, I guess cleaning would be very very hard. Kinda like cleaning a bowl you had cereal in at breakfast time a week ago, and you have not let it soak :S

  7. Vstress: I was just wondering about that. Does anyone know about the durability/reliability of caseless out in the field? How much real world experience is there with it? Not on a day or weekend exercise. On an extended deployment into Indian country?

  8. That is also an issue with a caseless round, and one of the main points is indeed the removal of an ejection port. You remove the currently loaded round by dropping the magazine, then charging the weapon, the round drops straight out the magazine well. Caseless rounds are 3-4x more expensive than cased rounds. Big point for the bean counters. Do you realize how many billions of dollars we’re talking for 1 year in Iraq? We’d need to double the defense budget.

  9. I heard that a serious problem with caseless ammo is that the case on a regular round absorbs a lot of the heat generated when the powder burns, and since it’s ejected, this removes the heat from the system (gun). Without this action, the gun action & barrel has to dissipate all its heat via conduction and air cooling (unless it’s liquid cooled), which is possible, but harder and generally requires more metal. This is why experimental caseless weapons tend to generate some worry about cookoff. It’s not an insurmountable obstacle, but I think it’s a concern. It’s also possible to develop a system which solves this problem another way, maybe carry a small amount of water in the weapon and spray it on the receiver in a fine mist after each firing? That might cause corrosion problems.. I’m not sure.. but it might also solve the heat issue without having the same speed and weight penalties of cased ammo. My main question is: what’s wrong with the M240? Is it too heavy? Can weight be saved with more advanced materials and a redesign, rather than a replacement? I know 7.62mm ammo is pretty heavy (at least if you’re carrying enough of it to make good use of an LMG), but too much of an emphasis on 5.56mm is a bad thing IMO. Sometimes you need to punch through cover, go out to longer distances accurately, etc. You want to have a tool nearby to do so. In short, having a few different types of weapon may cause some problems (e.g. logistics) but it lends a lot of flexibility. I’m curious what this 6.xxmm rounds are going to be like. I’m pretty sure, however good they are, it will always be possible to make 7.xxmm rounds which hit harder and 5.xxmm rounds which are lighter, so I doubt a new caliber can replace them *both* fully. It might be a good compromise though.

  10. In response to one of the posts in this string, there really aren’t that many problems with M240G,or ‘two-forty Gulf’ as most Marine Grunts call it. The M249 SAW which is basically just a smaller version of the same weapon chambered for 5.56 would seem just as good, and under ideal conditions it is a GREAT gun. HOWEVER, ideal conditions are nonexistant in the field. Durinbg my first tour in Iraq as a SAW gunner with Lima 3/5 1st MarDiv we were usually placed on air security up the rear hatch on our trax, the idea being automatic weapons better from a moving vehicle. It didn’t work out that way, after being topside for maybe 2 hours we were abushed, of the 6 SAWs in our platoon (we were heavy on SAWs all the line platoons in our BLT were) on two were operable during the initial engagement. I personally had my broken down and had to clean and lubricate it to get it back up. The frequency of these problems with the SAW are constant. it is a good concept, but poorly executed, the action needs to overmachined to compensate for normal field wear. Mind you when ever we dismounted (NOT under fire) we would clean and lube then move, and while foot mobile these problems dramatically reduced, but you still have problems maintaining sustained fire rates unless you use LSA as a lube (a much heavier lubricant than the CLP issued to line grunts) we jacked a jug of LSA from the Hvy Machine Gunners in CAT so our platoon did OK after that, but these things need to be worked out. As for the OICW its just ridiculously hvy. Even an extra pound makes a difference to a grunt. while i personally much prefer the 7.62×39 to the 5.56 in both knock down power and penetration it is highly unlikely that the us will ever change unless all of NATO does (hence the insanity of adopting 9mm the crappiest anti personel round ever conceaved, all because everybody else in NATO used it). Sorry to ramble so, but i would be extremely interested to see adoption of a hybrid round like the 6.5 or 6.8 guess we’ll see.

  11. As a future soldier and a student of history i have this to say: The guns dont weight to much they never did, my uncle carried a m60 all through Vietnam and got pretty pissed when they replaced it. As i understand from the gunners themselves they would rather have the bigger weapon and keep the power.

  12. well I have to agree with joshua,when my dad served with the 82nd in El Slavador, his platoon got ambushed rite when they hit they hit the LZ, most of the platoon didnt make it since barly anyone had on a flak vest, so my dad called on his 60′ gunner Sgt. Mesker, and that guy just made the 60 sing. All the guerillas that had ambushed my dad’s platoon dropped dead whne that 60 opened up. of cuorse the M-16 they were still using was still an old vietnam war era so they did kind of poorly. well on the option of caseless or not, I would rather see a hybrid, because I have read the pro’s and con’s on this subject.And i would like to see the M-60 brought back. I would not want any defective armor or weaponry or ammuniton when i gradutae as the class of 2010 and enlist int the Marine Corps.