graylion said:

So all those recoil mitigating mechanisms are the wrong way, since they slow down RoF?

IMHO and that of many others: yes. Ideally you would reduce recoil while keeping the ROF high. If that is not possible high ROF is to be prefered.
One of the main reasons why the MG5 is so controversial in the German military is its low ROF... among other things. The MG3 is still highly regarded and seen as the gold standard.
 

graylion said:

Try and design an LMG/SAW in 6.8x51 and highest possible RoF and find a bear to carry it? ;o)

6,8x51 is not so different to 7,62x51 and less powerfull than 7,92x57. The MG34 and MG42 used the latter and both guns where highly successfull in the LMG role. So is the MG3 which uses the 7,62x51. An average build european male can easily carry a 12 kg MG plus ready ammo. Has been done in the past and is still done today.

The LMG gunner should be strongly build in any case. Its allows for better gun/recoil controll and means he gets less tired while carrying. The LAW/RPG/Panzerfaust also isn't given to the one 1,65 m, 60 kg guy in the squad. Somtimes being tall and strong is an advantage.

schnuersi said:

An average build european male can easily carry a 12 kg MG plus ready ammo. Has been done in the past and is still done today.

LMGs are getting lighter anyway ...

So what about 8.5x63 for MMG with recoil moderating mechanism?

schnuersi said:

The MG3 is still highly regarded and seen as the gold standard.

Most reports I've seen have the MG3 set to a more sedate 850-900rpm (for example, Austrias MG3.)

Was that the case in Germany, or did they retain the higher RPM bolts?

graylion said:

6.8x51 would appear to be the GPC (Congrats Tony!)

No, not even close.  Tony's GPC was significantly smaller and much lighter than 7.62 NATO.

_____ 5.56 NATO ________ 6.5 GREN ___________ 6.5 GPC ____________ 7.62 NATO _______________

6.8x51 SIG is the same size -- and nearly as heavy -- as 7.62x51 NATO.

graylion said:

Also 6.8x51 would appear to be the GPC (Congrats Tony!) And people on this forum seem to agree that 8.5mm in a machine gun is a solution in search of a problem. remind me why? 

I think that a 80,000psi 6.5 Grendel or 6mm ARC (using Sig Hybrid tech) would be closer to Tony's GPC.

From what I recall, the 8.5mm machine gun just does not add enough capability to worth the trouble.  The bullet is to0 small to carry enough HE for anti-material roles, so it can't really replace the 50 BMG.

gatnerd said:

Most reports I've seen have the MG3 set to a more sedate 850-900rpm (for example, Austrias MG3.)

They are MG 74 and different to the MG 3

gatnerd said:

Was that the case in Germany, or did they retain the higher RPM bolts?

No, its the lighter bolt. The Bundeswehr MG 3 cycles at 1200 rpm.

graylion said:

LMGs are getting lighter anyway ...

Not really. The ones that are significantly lighter usually compromise capability, become flimsy or are made from (very) expensive materials.

graylion said:

So what about 8.5x63 for MMG with recoil moderating mechanism?

For an MMG the recoil absorbtion can be put into the mount. If one is required since the mount absorbs the recoil and vibration. If it is properly designed.

schnuersi said:

graylion said: LMGs are getting lighter anyway ... Not really. The ones that are significantly lighter usually compromise capability, become flimsy or are made from (very) expensive materials.

Like the FN Evolys?

https://fnherstal.com/en/defence/portable-weapons/fn-evolys-762/

schnuersi said:

The Bundeswehr MG 3 cycles at 1200 rpm.

Awesome. Are they still in production?

nincomp said:

From what I recall, the 8.5mm machine gun just does not add enough capability to worth the trouble.  The bullet is to0 small to carry enough HE for anti-material roles, so it can't really replace the 50 BMG.

How often does .50 HE get used?