US Army Considers Adopting an Interim Battle Rifle in 7.62NATO: eventually adopt 6.5

[LRRPF52]

The problem with the .224 and 6mm is that they do not pack enough energy to take on stone houses. Or mud brick houses. The Russians found that out with 5.45x39 in Chechnya.

6.5mm makes sense. Our heavy cartridge should be the .338NM (8.59x63) for the M240 and sniping.

And they still use 5.45x39 as their primary rifle cartridge, while augmenting it with semi-auto sniper support with 7.62x54R, and machine-gun support from 7.62x54R.

I can see the .338 being great to supplant and replace .50 BMG on vehicles, but not replace 7.62x51 NATO for dismounted machine-guns. No way does that make sense if you look at the weight of metallic cased .338NM for gun teams, which would be brutal. Now if you could make a .338 CT cartridge with the necessary performance to take advantage of .338 without exceeding the current weight of metallic 7.62 NATO, then you might have a good argument, but I can make a better argument for 6.5mm LSAT for dismounts with reduced ammo weight, and increased performance on target.

We have the opportunity to introduce a lightweight multi-role LMG that exceeds the performance of 7.62 NATO with less chamber pressure, less ammo weight and bulk, that also reaches well beyond 1000m when looking at the projectiles with .280 or higher G7 BCs.

When dealing with masonry and cinder block, as well as mud, belt-fed weapons and DMs or Snipers are preferred if we haven't AT4d or SMAW-D the building already. For simultaneous room clearance, the though of entry-level soldiers clearing rooms with over-penetrating cartridges scares me, as they aren't trained to do it well outside of Ranger Regiment, and Ranger Regiment has had many incidents of fratricide in the house over the years, even with all the training they do.

No conventional unit is going to even make a dent in the level of training Ranger Battalion does, even if their full chain of command within the Brigade tried to support it, because they are laden with so many training distractions from above the Brigade level, they can't possible fit relevant training into the schedule.

M855A1 already smokes cinder blocks as it is, which is more of a benefit to the SAW and a possible liability for the M4A1 for that target. With the amount of firepower an Infantry Squad and Platoon bring to bear, riflemen end up cleaning up the mess in the aftermath much of the time. They aren't a huge asset to firepower and decisive conclusions of heavy engagements outside of being able to facilitate maneuver due to their lighter weight and ammunition carrying capacity for endurance.