schnuersi said:

Range guessing is allways a propblem. Even for rifle and MG shooting. The difference is the impact of a grenade is much easier to spot.

Sure, ranging is important for those weapons at longer distances. But the average rifle can hit a mansize target without any sight adjustment easily at 300m-400m. Hell, I can shoot my Glock against a mansized steel target at 100m with 7/10 accuracy. 

The trajectory of a 40x46mm grenade by comparison is so extreme that a hit against a building cannot be assured from 50m if the trajectory is off - this marine puts his first round right into the road in front of him instead of the building across the steet:

https://www.youtube.com/watch?v=hvEmOJSoJOk

At 200m, the 40x46mm needs 10m elevation over the target:

I believe Emeric had the exact specs in his GPC paper? Listing the allowable ranging error at various distances for 40mm to put the round within lethal frag range? I recall the allowable aiming error being shockingly tight. 

...

The average rifleman might carry 2-3 rifle grenades? That doesn't leave a lot of spares for correcting aim if the first shot is off.

gatnerd said:

The trajectory of a 40x46mm grenade by comparison is so extreme that a hit against a building cannot be assured from 50m if the trajectory is off - this marine puts his first round right into the road in front of him instead of the building across the steet...

That video illustrates your point very well, but I would note that the target is the automobile, not the building.

1st round hit ~5 yards short of the car.  2nd round was ~10 yards over.  3rd round hit just below the car door.

Not a fan of rifle grenades, 40mm is already pushing it with regards to the compromise of number of rounds carried while still having some minimally useful effect on target.  Besides, you should be running suppressors anyway.

IMO, LAW, 40mm MV bounding HE-PFF (not LV HEDP), lightweight suicide drones and/or pike are where its at for individual HE beyond hand grenade range IMO.

With regards to rifle grenades and 40mm, one should assume you will need at least one if not more follow up shots either route you choose.  While the rifle grenade has a larger warhead, it is physically larger and heavier, and you have lower accuracy, lower range (particularly as 40mm MV starts to become more widely adopted), and fewer attempts. Does the larger warhead compensate for this? Perhaps, but I suspect not given most countries have switched to grenade launchers.  Proximity for airburst would certainly help, or even a scaled-up bounding function (which would be simpler and cheaper).

Despite it's smaller casualty radius, IMO the average soldier is more likely to get a 40mm MV close enough to a target to be effective, and since you can carry significantly more ammunition you get more attempts. 

The point of something like MGL (or this critter in the original post) is that you can complete your engagement (including adjusting fire) before having to reload, and even more useful, you can keep your sight picture throughout the engagement (unlike with single shot 40mm and rifle grenades) making finer adjustments easier.  This probably shines even more against fleeting targets of opportunity, like soldiers or vehicles darting across streets in urban terrain.  I would like to see MGLs at squad level (ideally fireteam level, with multiple per squad, but keep in mind I also prefer 5-6 man fireteams)

So, IMO, a soldier with a typical loadout of 40mm grenades should have more stowed kills than the same soldier with rifle grenades.  The larger ammunition load for the 40mm still isn't really as much as I'd like, but I'd be loathe to go smaller. Despite that, it does start getting into the relm of making reconnaissance by fire viable, while you might want to conserve your fewer rifle grenades for known targets... if you weren't using them quickly to break contact or dump weight on the already overburdened soldier.  My guess is a detonation near your position by either would be sufficient to get your undivided attention.

Speaking of overburdened soldiers, I do like the idea of 60mm commando mortars at platoon to compliment the platoon machine guns despite not being a fan of the arguably similar rifle grenades, but you'd almost certainly have to have everyone in the platoon carry a round or two.
 

The table at the end of this article   ( https://www.quarryhs.co.uk/GRENADES%20WEB%20ARTICLE.pdf ) provides some basic comparative stats.

Note that the cross-over point in system weight between 40mm rifled grenades and rifle grenades (ammo plus launcher) is about ten rounds.

How about (for default 8 man squad)

FT1

1. SL - M5
2. DM - M5 (longer barrel?)
3. Rifleman - M5
4. SAW - M250

FT2

• DSL - M5
• Rifleman - M5
• Rifleman - M5
• Grenadier - SSW

autogun said:

...the cross-over point in system weight between 40mm rifled grenades and rifle grenades (ammo plus launcher) is about ten rounds.

However, it looks like their bulk makes carrying ten rifle grenades somewhat problematic.

The number of rifle grenades that is practical to carry appears to be considerably less than ten.

To be fair, real estate would also be limited when it comes to carrying multiple huge magazines of the SSW. It fixes the biggest disadvantage of the MGL (aside from weight) which is reload time, but the tradeoff is bulky magazines and potential reliability issues in adverse environments (along with potentially temperamental auto regulation between ammunition types), and ammunition consumption remains a problem.

Something like the more traditional 40mm pouches / bandolier with MGL provides probably a better distribution of the bulk and weight of ammunition since the ammunition is smaller than rifle grenades and doesn't require a bulky magazine like the SSW... but at the cost of a bulkier firearm and much slower reload times as the gunner has to pull the grenades out of individual pouches

Solutions to mitigate that might include, inn no particular order:

-a fixed dispenser where individual rounds are presented and extracted (eliminating the need for multiple magazines but streamlining the time handling rounds vs trying to pull each out of a pouch under stress). However, what's the advantage of this over SSW magazines?  https://youtu.be/tzISRQOp0OA

Perbals an "iron man" backpack style instead?

-a simpler "bag o loose 40mm grenades" approach, dispensing with individual pouches altogether

-shifting doctrine to make an MGL a 2 or 3 man team with one person serving as a dedicated ammo bearer whose task is simply to get rounds out and ready to hand them to the gunner

- switching to a China Lake pump action like setup where you can load rounds individually like a shotgun after your short bout of 3-4 rounds of rapid fire to transition smoothly from rapid to sustained fire. 

-Having the MGL gunner also carry an M320 in the thigh holster and switch as necessary so they can both surge and sustain fires (unlikely, as the MGL is already heavy and bulky) 

-Accept the MGL reload time is excessive and make the gunner supplementary to the existing squad rather than replace one of the squad members (make the squad or fireteam larger) and have an M320 elsewhere in the fireteam as usual (ie, fireteam leader as in USMC)

-Opting for a simpler muzzle loading grenade launcher like Kastet and RG6

-Opt for thinner / longer grenade form factor (vog-17) 

I don't like something like the MGL at platoon simply because my understanding was that 40mm MV was really a 600 yard round at best even if it's ballistic range was further; a marked improvement over the LV, but not as far as one would like given the platoon MG can provide supporting fires from even further especially if on a tripod.  If we are talking 40mm HV it would be a different story, as you'd have much greater range, flatter trajectory and heavier weapon.

This is why I like the commando mortar at platoon, as it shares common ammunition with 60mm at company and the gunner can get rounds on the way instantly while the PL or FO is getting company mortars in the fight.

As a thought experiment I've played around with the idea of a 12 man squad - basically a typical 9 man squad but with a 3 man MGL team acting as sort of the squad leaders pocket artillery. This is in addition the 320s at fireteam level.  

The three man MGL team has two gunners and an ammo bearer (who also uses the laser rangefinder, has their own M320, and can also provide local security with their rifle).  This approach, treating it as a crew served rather than individual weapon, has some advantages over simply adding one to a squad or one to each fireteam as an individual weapon, in which down time to reload is excessive and ammunition is more limited.  The biggest drawbacks of the MGL (reload time and ammunition consumption) are both ameliorated with this method; reloads are faster as part of a team since the ammo bearer can ready and present the rounds to the gunner, can lase range. Downtime is reduced since gunners can take turns for sustained fires or surge by combining fires when appropriate.  Finally, the ammo bearer of course brings more ammunition.

The USMC has it exactly backwards, IMO. The Gustav should be at platoon (with AT4/M72 at squad), while MGL and belt fed 5.56 should be at squad. 

Refleks said:

To be fair, real estate would also be limited when it comes to carrying multiple huge magazines of the SSW.

Certainly.  But the SSW space issue does not look to be nearly as bad as carrying rifle grenades. 

Judging by the MAG-D system (below), the SSW grenadier might be able to carry four magazines,

That's 24 rounds of 40mm ammo in about the same space needed to carry eight rifle grenades.

There was potentially another approach to this class of weapon, as I suggested some years ago: https://www.quarryhs.co.uk/MetalStorm.htm

Sadly, it seems that Metal Storm finally expired a few years ago.

A semi auto, tube fed design might be optimal, such as envisioned by STK's SSW, which is either a 3+1 or 4+1 semi auto:

Tube fed eliminates the bulk of a magazine, as well as the width of a drum.

And it also allows the gun to be 'topped up' with 1-2 rounds between firings like a shotgun.