7.62x51/.308 Replacement Help

[UKKnowledgeSeeker]

After a long break I am back once more to delve into technical matters with the help of fellow THR members.

In the scenario that the 6.5x39 is adopted as the main service cartridge it is my thinking that the 7.62x51 would be made unnecessary. The 6.5 Grendel has comparable levels of energy whilst being lighter, smaller, more pleasant to fire etcetera. However the gap between 6.5 Grendel & .50 BMG needs to be filled with a rifle round. Seeing the evident efficiency of the 6.5x39 a high Ballistic Coefficient evidently improves ballistics & energy retention.

Either 7mm-08 or 6.5x55 occurred to me although I have limited knowledge in this area. Or is there something that can be done to the 7.62 NATO?

As the round is for military purposes, rather than hunting or target shooting are there any factors that would make the round in question unsuitable of military use? Barrel wear, excessive noise & flash, incompatibility with self loading mechanisms and belt fed systems?


The round must have...


• No more than 2800 ft.-lb.*of muzzle energy preferably around 2600 ft.-lb.

• A maximum effective range of at least 1100 yards against personnel

• Have noticeably superior ballistics & energy retention than the M118 LR 7.62 NATO

•The capability to be used in a belt fed system or in a self loading/automatic rifle


The more detailed & specific answer the better (within reason).


Thanks in advance, Ben.

 

[Zak Smith]

6.5 Grendel does not outperform .308 as a general statement. You may be able to find a barrel length combination where the 6.5 Grendel has better downrange performance than .308, or find that a great match load in 6.5 Grendel exceeds a "Ball" load in .308.

If you want something that has much better ballistics from a ".308 sized cartridge", we've been discussing and using the alternatives in field/practical long range shooting for some time.


article | The Case for .260 Remington: A Better Cartridge For Practical Long-Range Shooting



article | 6.5mm Shootout: .260 Remington vs. 6.5x47 Lapua vs. 6.5 Creedmoor


article | 6.5 Creedmoor - .260 Done Right?


article | The 6.5x47 Lapua Tactical Rifle

It makes more sense to define the action size and overall cartridge size parameters. The 6.5 Grendel, .308/7-08, and 6.5x55 all fit different action lengths ("AR-15", "short action" and "AR-10", and "Mauser" or "long action").

Instead of a theoretical discussion of a theoretical future military cartridge, we could discuss actual applications and real-world performance of actual cartridges.

The likelihood that 6.5 Grendel will be adopted as the infantry cartridge is basically zero.

By the way, there are already some cartridges in military use between 5.56 and .50BMG: .300WM and .338LM to name two.