OPTIMUM military caliber report

[malern28us]

Not sure but I think a standard 30 round ar mag will only hold 26 rounds of 6.5 grendel

So, not only a round count penalty but also a weight penalty? Doesn't seem like a worthwhile trade off.

 

[jeremy]

Curious, to see where this may go....

 

[malern28us]

Curious, to see where this may go....

I am just curious as to the whole thing. I would think at this point our military is just biding time for "smart" rifles or mini rail guns

 

[worddoer]

Keep in mind that there is a HUGE logistics issue here. I believe that our military is expecting huge budget cuts in the future. So anything they do will be based strongly on the financial repercussions. I believe that starting an entire new platform is out of the question.

This is my somewhat educated guess, but the most you would see is something that can fit in the AR / M16 / M4 platform. Especially if all they need to do is a barrel, bolt and possibly mag change. That can be done much easier and keeps costs down significantly.

Keep in mind that the underlying reason we have the 5.56 today is because of cost. Ya it started with commonality with our NATO allies & wanting more ammo capacity for our soldiers, ect, ect. But there were other options back in the day. There was a large financial motivation involved. Having one common caliber means more ammo production in that caliber which translates to savings. Dollars make decisions in the end.

If we move to a common caliber, hopefully it is something that gives our troops an advantage. Rather than a downgrade. For example, I could see the .300 Blackout being a contender based purely on cost alone. The only change needed to the weapon systems is the barrel (hence saving money) and it uses existing components for ammo production (hence saving money). But based on my understanding of the cartridge, it is inferior to the 6.5 Grendal.

 

[giovani]

Keep in mind that there is a HUGE logistics issue here. I believe that our military is expecting huge budget cuts in the future. So anything they do will be based strongly on the financial repercussions. I believe that starting an entire new platform is out of the question.

This is my somewhat educated guess, but the most you would see is something that can fit in the AR / M16 / M4 platform. Especially if all they need to do is a barrel, bolt and possibly mag change. That can be done much easier and keeps costs down significantly.

Keep in mind that the underlying reason we have the 5.56 today is because of cost. Ya it started with commonality with our NATO allies & wanting more ammo capacity for our soldiers, ect, ect. But there were other options back in the day. There was a large financial motivation involved. Having one common caliber means more ammo production in that caliber which translates to savings. Dollars make decisions in the end.

If we move to a common caliber, hopefully it is something that gives our troops an advantage. Rather than a downgrade. For example, I could see the .300 Blackout being a contender based purely on cost alone. The only change needed to the weapon systems is the barrel (hence saving money) and it uses existing components for ammo production (hence saving money). But based on my understanding of the cartridge, it is inferior to the 6.5 Grendal.

And the U.S. will have to convince all of our allies, some of these countrys also not doing well economically that they need to make a change that will be very expensive.

 

[ckcollins2003]

So do we change calibers for every different war?
Or do we do what the miltary currently does and supply most of our troops with M4s which from what I read they preffer to M16 for house cleaning and attach at least one person with a weapon of larger caliber to take care of the long distance targets.

actually it would be good to here from someone that has come back from afganistan on their opinion.
It would be far better than anyone's including mine as I have not been there.

Ask any grunt whether or not the 5.56 gets the job done and they will tell you the same thing. It works. "It works well on soft targets and that's what matters." There have been confirmed kills out to 650+ yards with an M4. Luck? Possibly a bit, but training has more to do with the war than what you're lobbing out into center field. There are 240B gunners in every squad and usually snipers set up as over-watch on just about every mission.

Our country can't afford a more expensive caliber, nor do we need it. If you want a better fighting man, train him better. We already have a great weapon system.

You can give a MARSOC operator a pistol and put him up against Joe Schmoe with a rifle. And in the environment that our war is fought in, the operator will win because of training and experience.

 

[downzero]

I'd rather see them use a 6mm bullet rather than a 6.5mm, although either would work. With similar powder capacity, 6mm would fly flatter whereas 6.5 would fly further with more drop. In a bigger case or with a longer barrel, 6.5 would be better. 6mm would probably have less recoil as well.

Either way, what we are talking about is essentially a 7.62x39 with a proper size and weight of bullet to reflect its powder capacity (hint: 123 grain 7.62 is too heavy and too big in diameter).

Our snipers should be using a 7mm bullet unless we want them using a magnum caliber.

 

[Matt52]

So, not only a round count penalty but also a weight penalty? Doesn't seem like a worthwhile trade off.

This could always be adjusted for. Most guys only load 28 rounds in a 30 rd 5.56 mag for added reliablility.

 

[Matt52]

I'd rather see them use a 6mm bullet rather than a 6.5mm, although either would work. With similar powder capacity, 6mm would fly flatter whereas 6.5 would fly further with more drop. In a bigger case or with a longer barrel, 6.5 would be better. 6mm would probably have less recoil as well.

Either way, what we are talking about is essentially a 7.62x39 with a proper size and weight of bullet to reflect its powder capacity (hint: 123 grain 7.62 is too heavy and too big in diameter).

Our snipers should be using a 7mm bullet unless we want them using a magnum caliber.

Im pretty sure the 6.5 is the king of long range slightly better than the 6mm. Based on BC.

 

[downzero]

Im pretty sure the 6.5 is the king of long range slightly better than the 6mm. Based of BC.

A BC doesn't mean anything without velocity and some recognition of powder capacity.

Surely you recognize that 222 Remington and 220 Swift aren't the same cartridge even though they use the same bullets.

6.5 Grendel is a great cartridge, but for a carbine barrel length and the capacity of the case, a 6mm bullet would probably perform better. What I mean by that is when you consider the powder capacity available, the barrel length available, and the range it'd be expected to be used, the 6mm bullet will fly flatter, which makes it more useful, even if its maximum supersonic range is shorter.

Keep in mind also that BC doesn't mean squat without considering the powder capacity. The .30 caliber, 240 grain Sierra Match King has a BC of .711, which is substantially higher than any 6.5 or 7mm bullet available. The problem is that no non-magnum case has enough powder capacity to launch it at a useful velocity.

A 6mm 115 grain SMK has a BC of about .550. The 142 grain 6.5mm is .580 below 2800 FPS. The next step lighter for bullet weights for those calibers are .520 and .530 respectively. Now consider you had the same amount of powder capacity to launch both bullets and how do you think they'd perform?

If velocity were equal, the one with a higher BC would perform better. But when the BCs are that close together, and one has the potential to leave the barrel at a significantly higher velocity, I think it becomes a much tougher question, especially when most shots are not at the fringe of supersonic range.

Also note that this is all just for the sake of argument, because no army could afford to load match kings for all of its soldiers. I only used those numbers as illustrations; FMJ bullets will have significantly lower BCs, but the relationship between diameter and BC would be about the same. Only the scale would change if I'd used FMJ numbers instead.

The "king" of long range always depends on powder capacity. The 300 grain .338 > .30 cal 240 > 180 grain 7mm > 142 grain 6.5mm and so on. But you need a lot of powder to make use of these bullets, and the AR action is only so long.

 

[Iroquois]

The thin jackets and heavy crimp canular (ignore the spelling) made the 55gr .556 very fragile
and often useless in heavy brush. This was remedied by adding a steel penetrator inside the
bullet. This resulted in over penetration and lack of damage in Somalia, with " skinnies " getting
back up and running away. (Blackhawk Down)
We've seen some experimenting in Iraq with 6.8 bullets with mixed results.
I'd like to see some serious experimentation with larger bullets to provide longer range
effective hits out of a 17" to 19" barrel. One advantage could be barrier penetration
with a hardened tungsten core. Greater durability of the bullet in brush might be a benefit.
A 6.5 might fit the bill and the M 14 could be barreled to. 260. Rem for longer shots.
That would reduce number of calibers for barrel making in a real SHTF war scenario.
Not that I think we're gonna change anything soon but if we did decide to change uppers
it might be a good time to consider ammo change....just a few ideas.

 

[Matt52]

You are sadly mistaken. You may think this to be true but it has been proven that this is not cost effective. Using your logic, we shoulkd give every soldier a .338 Lapua and let them go wild.

Im speaking about the sub 30 caliber class and particularly the ones that fit in an AR platform.

 

[Matt52]

A BC doesn't mean anything without velocity and some recognition of powder capacity.

Surely you recognize that 222 Remington and 220 Swift aren't the same cartridge even though they use the same bullets.

6.5 Grendel is a great cartridge, but for a carbine barrel length and the capacity of the case, a 6mm bullet would probably perform better. What I mean by that is when you consider the powder capacity available, the barrel length available, and the range it'd be expected to be used, the 6mm bullet will fly flatter, which makes it more useful, even if its maximum supersonic range is shorter.

Keep in mind also that BC doesn't mean squat without considering the powder capacity. The .30 caliber, 240 grain Sierra Match King has a BC of .711, which is substantially higher than any 6.5 or 7mm bullet available. The problem is that no non-magnum case has enough powder capacity to launch it at a useful velocity.

A 6mm 115 grain SMK has a BC of about .550. The 142 grain 6.5mm is .580 below 2800 FPS. The next step lighter for bullet weights for those calibers are .520 and .530 respectively. Now consider you had the same amount of powder capacity to launch both bullets and how do you think they'd perform?

If velocity were equal, the one with a higher BC would perform better. But when the BCs are that close together, and one has the potential to leave the barrel at a significantly higher velocity, I think it becomes a much tougher question, especially when most shots are not at the fringe of supersonic range.

Also note that this is all just for the sake of argument, because no army could afford to load match kings for all of its soldiers. I only used those numbers as illustrations; FMJ bullets will have significantly lower BCs, but the relationship between diameter and BC would be about the same. Only the scale would change if I'd used FMJ numbers instead.

The "king" of long range always depends on powder capacity. The 300 grain .338 > .30 cal 240 > 180 grain 7mm > 142 grain 6.5mm and so on. But you need a lot of powder to make use of these bullets, and the AR action is only so long.

Thats what makes the 6.5 grendel so useful it accomplishes that goal better than any cartridge for the AR at this moment.

 

[Cerberus]

This could always be adjusted for. Most guys only load 28 rounds in a 30 rd 5.56 mag for added reliablility.

Did we? This is not a practice I've seen in usage since the late 80s.

 

[downzero]

Thats what makes the 6.5 grendel so useful it accomplishes that goal better than any cartridge for the AR at this moment.

I don't think that's the case at all. A 6.5 Grendel necked down to 6mm, with the right bullets, would probably surpass the performance of straight 6.5 Grendel.

Check out this website: 6mmAR -- 6mm Solution for AR-15s (Grendel Brass)

And take a look at the numbers for yourself. Keep in mind that those numbers are with 105 grain bullets. With 115 Sierras I bet that it's even more impressive. Keep in mind also that there are even better performing 6mm AR cartridges out there; the one for that article is the easiest one to make because it uses regular Grendel brass.

I really wanted a Grendel but I think that the 6mm payload is better suited to that case capacity.

 

[Matt52]

Did we? This is not a practice I've seen in usage since the late 80s.

Its my understanding that it is something of recent practice. The theory is its not compressing the spring as tight in the mag as it would be when fully loaded. Cant verify it has a ton of merit

 

[the1kidd03]

Some guys do, some don't. Most mags are WELL used and don't often have a need for "under-loading" them. I never did personally.

 

[jeremy]

This could always be adjusted for. Most guys only load 28 rounds in a 30 rd 5.56 mag for added reliablility.

I would smoke the hell out of any of mine that underloaded their Mags to 28...

That is leaving half a Mag out of your Combat Load!

 

[malern28us]

Its my understanding that it is something of recent practice. The theory is its not compressing the spring as tight in the mag as it would be when fully loaded. Cant verify it has a ton of merit

This would seem counter productive. If you dont trust the mags, I would think you would use something else or buy your own. If it was my a$$ on the line, I would spare no personal expense. Thats just me though.

 

[malern28us]

sorry double post