Let's design a new service rifle and cartridge...

[JusticeM4]

I'm no expert in ballistics or military weapons, but purely from a civilian opinion here is my take:

1. Why not the 300BLK on an AR platform, possibly SBR like the HK416 for CQB purposes? 10-16inch barrel with AAC flash hider depending on the Unit. Anything under 150yards, the 300BLK should suffice.
Issue a specific optic with 300BLK BDC from Trijicon or Aimpoint with the rifle.

2. SCAR16/17 or AR10. If I were to choose any other caliber other than 5.56 or 300BLK, I would go straight to 7.62NATO. Effective up to 800yards if needed.
No need for any other cartridges like 6.8/6.5/7.62x39 IMO.

[Koshinn]

I'm no expert in ballistics or military weapons, but purely from a civilian opinion here is my take:

1. Why not the 300BLK on an AR platform, possibly SBR like the HK416 for CQB purposes? 10-16inch barrel with AAC flash hider depending on the Unit. Anything under 150yards, the 300BLK should suffice.
Issue a specific optic with 300BLK BDC from Trijicon or Aimpoint with the rifle.

2. SCAR16/17 or AR10. If I were to choose any other caliber other than 5.56 or 300BLK, I would go straight to 7.62NATO. Effective up to 800yards if needed.
No need for any other cartridges like 6.8/6.5/7.62x39 IMO.

There are times when you transition from close quarters to shooting across a valley before returning to base. A specialty caliber like 300blk probably isn't a good idea for general issue for that reason. Even city streets can be longer than 200 yds.

[Failure2Stop]

6.8 is hobbled from the start. The case wants and needs a larger receiver to do the job it is being asked to do. Are there benefits to the 6.8? Absolutely. But it would do even better if given the case capacity and structural support to push more.

Militaries and special units all over are coming back to 7.62, but not because they "need" 7.62, but rather that they need more than 5.56, and it is the simplest way to achieve the increase in effectiveness and range without going to specialty ammunition. If a true intermediate cartridge solution existed, I bet that it would gain a strong following. The issue is cost versus benefit, and frankly, the cost of retooling to build a new small arm cartridge is simply not worth the benefit in the grand scheme of things. This self imposed resistance to change stifles solutions.


Typos brought to you via Tapatalk and autocorrect.

[BoringGuy45]

6.8 is hobbled from the start. The case wants and needs a larger receiver to do the job it is being asked to do. Are there benefits to the 6.8? Absolutely. But it would do even better if given the case capacity and structural support to push more.

Militaries and special units all over are coming back to 7.62, but not because they "need" 7.62, but rather that they need more than 5.56, and it is the simplest way to achieve the increase in effectiveness and range without going to specialty ammunition. If a true intermediate cartridge solution existed, I bet that it would gain a strong following. The issue is cost versus benefit, and frankly, the cost of retooling to build a new small arm cartridge is simply not worth the benefit in the grand scheme of things. This self imposed resistance to change stifles solutions.


Typos brought to you via Tapatalk and autocorrect.

Exactly. I can't help wonder what the ballistics would be if the case were 45-47mm as opposed to 43.

[Failure2Stop]

I just want to clarify my previous post.

I am not saying that trying to advance is futile, simply that advancement on a "better than 5.56 cartridge" has been stifled due to budget constraints.

[Dano5326]

Improving rifle/cartridge assumes a level of profiency able exploit ballistic gains; distance, accuracy, terminal effects, etc.

I do not see any need for conventional forces beyond a PIP'd M4. The weight, bulk for the individual would go past diminishing returns.. Straight into a performance penalty. For the service the logs, training, cost burden doesn't make sense.

SOF would benefit immediately, from currently being performance limited by equipment, not profiency. Also, a smaller more agile system is better placed to train equip field and sustain effectively.

I would suggest AR ergos and a similiar modular upper/lower template. 6.5mm (maybe to 7mm) has some amazing BC rounds of sufficient weight to have good terminal ballistics.

[556.45.12]

I'm digging the caseless ammo suggestion and also agree with the poster on not deviating too far from what makes the AR great (and end-user serviceable). Some kind of AR that fires 4.73×33mm caseless out of a new magazine/feed system would be my choice. A soldier could enter the battlefield with 100 rounds on tap in the same weight rifle that our troops are carrying now, with all of that familiarity on tap. The ammo has already been invented and thoroughly tested. All the money saved on brass would pay for the cost of the project after only a few years probably.

[MistWolf]

For now, caseless ammo is very expensive. When the Germans fielded the G11, cost for a single round was about $22.

Other problems include protecting the propellant from the environment, fragility and susceptibility to cook offs

[Koshinn]

For now, caseless ammo is very expensive. When the Germans fielded the G11, cost for a single round was about $22.

Other problems include protecting the propellant from the environment, fragility and susceptibility to cook offs

The LSAT is a LMG that, in one variant, uses caseless ammo. I'm not privy to all the info on the LSAT project, but if they're going to use it in a support fire role, I think the cost has at least somewhat been addresesd.

[justin_247]

Are there benefits to the 6.8? Absolutely. But it would do even better if given the case capacity and structural support to push more.

...

Militaries and special units all over are coming back to 7.62, but not because they "need" 7.62, but rather that they need more than 5.56, and it is the simplest way to achieve the increase in effectiveness and range without going to specialty ammunition. If a true intermediate cartridge solution existed, I bet that it would gain a strong following. The issue is cost versus benefit, and frankly, the cost of retooling to build a new small arm cartridge is simply not worth the benefit in the grand scheme of things. This self imposed resistance to change stifles solutions.

I think this is an important point. While the cost of retooling an entire country (actually, more like all of Europe and North America, since we operate with NATO) is excessive, the rifle should be relatively easy to rechamber for different calibers. With this in mind, having a standard magwell that goes all the way up to 7.62x51 is very important - just swapping out the upper and installing a block means you can run every kind of ammo from .22 LR and various handgun cartridges all the way up to 7.62x51 and various shotgun cartridges.

The Colt CM901 seems like a step in the right direction to me.