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There wasnt enough room in the title to really finish the question I was trying to ask here.

My question is: Lets say Nato asked YOU to decide upon a cartridge that would be used by ALL NATO countries in their assault rifles and LMG's/SMG's, and money or cost of ammo was no object, which cartridge would you choose?:wacko:

Would you stick with 5.56 x 45mm, or would you decide upon another cartridge? Lets make a rule here. Lets say that you can choose a cartridge that maybe doesnt chamber a huge selection of bullets. But you can choose that cartridge and say: "I choose 6mmBR(example), but I'd design a new penetrator bullet for it like the M855", for instance.

So which cartridge would you choose if you had the future of NATO small arms to decide?;)

To be honest, now that I've typed the thread, I cant really think of a great cartridge that would fill all requirements, such as: size, weight, fitment, knock down power, velocity, range, etc.......<_<

*1. I like the 6.5 MPC. It is 6.5 X 42mm. Uses a standard NATO 5.56x45 brass case, shortened by 3mm. It's neck is modified. It will push a 95 grain bullet at 2800 ft/sec out of a 20" barrel, or 2600 ft/sec out of 12" barrel. It supposedly has 30-50% more terminal energy than 5.56 x 45mm.

OR.....

*2. 6mm PPC(6x38mm). The problem here is that it is made from a 220 Russian case, so the US military might not like that! But it has good specs. 65gr bullet, 3100 ft/sec 16" barrel, 70gr 3000 ft/sec

OR....

*3. 6.5 Grendel(6.5 x 38.7mm) Also from .220 Russian brass. Specs: 120gr bullet, 2470 ft/sec from 16" barrel.

I chose those 3 because they should be able to be shoehorned into current NATO assault rifles, and their magazines. If that wasnt important, maybe I'd choose other cartridges. The only issues are that these cartridges weigh more, so you'd have to carry less ammo for the same weight. But they would give us better knock down power in our assault rifles, and better range......

Of the 3 listed, I think I like the 6.5 MPC best, followed by 6mmPPC. Narrowing it to those 2 gives me 2 cartridges with significantly different bullet weights to decide from.:D

But I'll say that I have not spent much time trying to figure out which cartridge would be best for future assault rifles. I'd also prefer to adopt a new assault rifle as well. But that is a different thread.

Anyway, your choice does not have to fit current NATO magazines or does it have to be usable in NATO assault rifles once they are modified with new barrels, etc. You can choose ANY cartridge, any size you want......
 

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I am going to have to go with the 6.8SPC simply because that would make surplus ammo available at a reasonable price and I could stock up in prep for the zombie apocalypse.
The 6x45 sounds interesting as well, may be my next build, all that is required is to run a 6mm neck sizing die through .223 brass and your in business, change out the barrel, keep the same mags, GTG with a .243caliber round from an M/16/M4 AR15. Wouldn't take much refitting, More efficient killer than the .223 but no gain in weight or bulk to speak of in ammo carrying capacity.
 

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Well I don't know about some of those rounds (never tried any of them),
but I'd stick with .223/5.56 and 7.62x39 for NATO purposes common and cheap!

Figure it this way; if your in a foriegn land and out of ammo, what does your dead enemy have left??
 

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I would go with the 6.8 SPC II. It would be in weights between 85gr-95gr, not sure which, but those have great velocity for the round, great knockdown, and are lighter than some of the heavier 6.8 offerings, allowing for the grunts to lug more of them around. The increase is recoil is also minor and can be negated with a heavier buffer and spring and/or a muzzle brake.

Obviously, new magazines would need to be designed (you listening Magpul?) to be able to reliably feed with. And yes, as Alaj pointed out, this would create a surplus market for us 6.8 shooters who think that buying several hundred rounds at $17 per/20 is a good buy.

I think this round provides the essential increase in knockdown power required nowadays, with the ability to still carry a standard battle load. And it is still able to reach out past where the 5.56 can't and do it accurately, thus creating an overlap between rifleman/SDM/sniper ranges. I would also insist on a 16" barrel (at least medium weight) to get the best accuracy and velocity and still have it be fairly maneuverable.

I think I read that the Czech military has a new rifle (CZ S 805) and they are looking to adopt the 6.8 for it. Or, it may be another nation in the Balkans region or around there that adopted the round, but that is fairly promising for the round. And now, TulAmmo is preparing to make the 6.8. Not sure if it is good or bad news, but we will see.

TG
 

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OP, I do not mean to highjack your thread, but how about the .30 Remington AR?

It shoots a 30 caliber bullet, with bullet weights anywhere from 110 grain all the way to 150 grain.

American Rifleman magazine had a write up about the 30 Remington AR in its March 2011 issue on page 66.
 

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Yes, I have been interested in the 30 RAR as well. It seems like a great cartridge but for some reason it doesn't seem to be catching on. Remington designed it for their new X15 rifle and it doesn't appear like you can even buy that rifle chambered for the round. I'd love to see someone start making barrels and such for it.
 

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I am surprised no one mentioned the 300 Blackout, the ability to fire a thirty caliber bullet at sub sonic or supersonic velocities while still using unmodified AR-15 magazines and bolt groups is a definite benefit.
 

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;)Personally-I cannot see continuing to use the "rat gun"rounds any longer unless somebody can defy physics and make a 5.56x45 round that fires at 4000+fps,makes over 2kft/lbs energy, won't wash out barrels,and that the std ar platform can fire without grenading!I would like to see something based off of the 308/7.62 nato round on an ar-10 platform. .243 winchester,257 roberts,6.5 something,270/308,7mm08,or just leave the 308/7.62 nato as is!Look at some of the ar-10 platforms from Armalite nowadays-I just don't see a need for 5.56 in a frontline combat environment.Maybe rear echelon security situations!:huh:
 

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That study has been done multiple times by different countries / groups since the early 1900s. Every group has come to the same conclusion: the ideal military rifle/LMG round has a 6mm - 7mm bullet of 90 - 130 gr with a MV of 2500-2800 fps. The ubiquity of the assault rifle concept postwar and the necessity for controllable full-auto fire pushed the ideal toward the lower end of that envelope.
Every time a different group has come to that conclusion, political considerations have caused the adoption of something else.

The ideal GP cartridge would be a 6.5mm with a relatively high BC bullet of 110gr with a muzzle velocity of 2700fps.

As it happens, both the 6.8 Rem and 6.5 Grendel fall within that range of "good", with the Grendel more closely approaching the ideal balance. The AR boltface and magwell will accommodate both cartridges, but the Grendel's larger casehead leads to a greater incidence of broken bolts. The 6.8 doesn't have the long range capabilities of the Grendel.

Since the original question postulates unlimited funds and makes it unnecassary to keep the existing designs, I would scrap all the AR-based rifles / carbines in the inventory by selling them to we civilians, and build the new standard rifle around a slightly longer Grendel that would allow 120gr bullets to make 2700fps out of a 12" barrel. While initial issue ammo would be the ideal 110/2700, this would allow for future development of bullet types (tracer, AP, etc.) without too many compromises.
New rifle design was not asked, but I'd like to see a user-configurable, fully-ambi bullpup with a 16" barrel.
 

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Personally I would go back to the 7.62X51. Or more commonly known as the .308. Go to an M1A, M14 style rifle as well. There are many flavors of them now, full length, carbine length and in between.
It is well documented that the .30 caliber bullet is far superior to the .22 caliber.
 
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;)I would like to see something based off of the 308/7.62 nato round on an ar-10 platform. .243 winchester,257 roberts,6.5 something,270/308,7mm08,or just leave the 308/7.62 nato as is!Look at some of the ar-10 platforms from Armalite nowadays-I just don't see a need for 5.56 in a frontline combat environment.Maybe rear echelon security situations!:huh:
I agree wholeheartedly that the 5.56 must go! However, by switching to the LR-308/AR-10 platform, you are adding unnecessary weight to what the grunts are already toting around. (Yes, I know snipers and SDM's use this rifle, but they aren't EVERY grunt). When it is all said and done, a basic AR-10/LR-308 platform weighs nearly 9 lbs empty. You put a mag and optic on there and you are flirting with the weight of an M249 SAW (empty).

The trick is trying to maintain a lighter platform like the AR15 and being able to utilize more lethal rounds in that size of a platform. It is a difficult feat, but it can be done. It is just a matter of who is greasing the politicians palms...

With some of the 6.8 offerings from SSA, their 75-95 gr loads are ranging from 2700-3100 fps and producing between 1500-1800 fpe. Pretty good performance over the 5.56, especially considering that SAW/SMGs will be loaded a tad hotter than the standard rifle round. Especially with all the different types of rounds available for this caliber now, it just seems to be the best solution to this age-old issue.

Personally I would go back to the 7.62X51. Or more commonly known as the .308. Go to an M1A, M14 style rifle as well. There are many flavors of them now, full length, carbine length and in between.
It is well documented that the .30 caliber bullet is far superior to the .22 caliber.
I agree that the 7.62x51 is far superior to the 5.56. However, by making this the standard round again, you are decreasing the standard battle load significantly due to weight. And you are increasing the weight of the rifle quite a bit if you go with an M14 or AR-10/LR-308 platform. That just seems to be a lose/lose for the grunts.

I am surprised no one mentioned the 300 Blackout.
The 300 Blackout is a good round, within 200 yards. Unfortunately, our guys are frequently engaged out to 600 yards presently and the 5.56 just can't cut it at those ranges. Maintaining the AR15 platform or one as light as it is critical though.

TG
 

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Yes the rifles are heavier and so is the ammo but I bet if you gave the combat troops a poll they would choose the weight and stopping power over the lighter weight and ammo that sometimes bounces off of windshields.

.30 caliber turns cover into concealment.
 

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I'm a combat troop and I would vote for the smaller, lighter, more maneuverable platform with a more potent round such as the 6.8 so that I could maintain a large battle load without overburdening myself. Especially considering I may be engaged with the enemy for hours on end, I want to carry all I can into battle. I would rather have 300 rds of 6.8 than 180 rds of 7.62x51.

TG
 

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I would have to go with either the 6x45mm or the 6.5 Grendel.

I do have a 6x45 upper for my Ar and its a great perfroming little round, with a good ballance of bullet weight + velocity + Ballistics. In my opinion its a good bit more harder hitting than the 5.56.
 

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One problem that I see, it companies making oddball cartridges for no reason.

If you want something larger then a 223, go with a 243 or something like a 257 roberts.

Why do we need dozens of oddball calibers that serve no real purpose.
 

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If you want something larger then a 223, go with a 243 or something like a 257 roberts.
In this scenario where cost is of no importance that would be great, I would probably say go with the 7mm-08 but in the real world, .243 or 257 won't fit an AR length magazine. I was basing the cartridge on something that would be an easy conversion for the M16/m4. Also, you would want to keep weight to a minimum so that the guy in the field can carry a maximum amount of ammo without being overloaded. The 6x45 would be the simplest of all to accomplish this since it would use the same magazines. The ammo manufacturers would have only the minimum of retooliing since their is no change to brass at all other than resizing the neck and the weapon itself would require nothing but a barrel change. Weight difference would be minimal, +/- 35gr per round, at 7000grains per pound that would only be 1 pound extra for every 200 rounds.
 

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As an "assualt rifle" round (and LMG/SAW round), NATO is heavily ingrained with and invested in the 5.56x45. A radical shift away from it at this point would be rather unlikely.

As much as I like some of the other cartridges mentioned from a ballistic standpoint - like the Grendel, 7.62 NATO, etc. - they would require expensive platform changes and "bigger/longer" cartridges tend to push us out of the "assult rifle" category and back into the "main battle rifle" realm.

To that end, data on the 6X45 (take a .223 case and neck up to take a .243 bullet) would seem to make it ideal from ballistic, upgrade cost-efficiency and weapon platform/training consistency standpoints. Really, all you need is a barrel change. It's a shame that round hasn't been considered more seriously.

Outside of the 6x45, I'd lean towards the 6.8SPCII for similar reasons.
 

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6x45 or 6x47 slightly longer case length. With something along the lines of an 80 to 90 grain projctile. This would be a great round and cost effective to boot!
 
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