Grendel as a Universal Infantry Cartridge

[RedFalconBill]

Are you suggesting that 2450-2600 ft/sec is a desirable MV, or are you indicating that that's all we might get from a particular cartridge?

Given the STANAG magazine well, my suggested muzzle velocity is about all we will get with a chamber pressure in the 50,000 psi range. Going to a larger case, or higher pressure, will provide more velocity, but there is a diminishing return here with regards to muzzle blast, recoil, and even lower basic load.

What do you have in mind for cartridge more suited to our needs?

For what Infantry needs:

The .250 Savage with a 100 to 117gr bullet or a 6.5-250 Savage with a 107gr to 129gr bullet. A lot of case taper for its 1.912" case length, and the use of the 0.473" case head means that you are really limiting the basic load of soldiers.

Of course, if we wanted less case taper and a smaller case head, we could use the Carcano/M-S, but then the overall cartridge length would be around 2.75". Not very space efficient and using 19th century case designs will not win you any friends.

The 7.62x45mm Czech case is intriguing. Necked down to 0.264" and with much of its taper taken out, it has almost 20% case capacity than either the SPC or the Grendel case, but has 20% less capacity than the Carcano/M-S cases. With an overall cartridge length of around 2.500", a 14.5" barrel should get ~2,500fps with a 120gr to 125gr bullet, and a 20" barrel might get up to 2,700fps.

I do not see any of these thoughts as viable, even though they are good ideas. We have no money, and no enthusiasm, to fund R&D for this, the US no longer has a large, vibrant, firearms community, the EU is just fine with puny defense budgets, and lastly, no NCO above the rank of E-6 and no Officer above the rank of O-3 really care about small arms.

Does this mean that the solution is better and more training and stay with the same cartridge?

Better training, yes. Dumping the M855/M855A1 bullet and going with a Mk318 bullet concept (which can be bonded, or not, have the core in the front, or the rear, and have the core made of lead, or not), would give a boost in lethality in the 5.56 cartridge.