The U.S. Army Chose a New Bullet for Its New Rifles
- Thread starter ProgSpear
- Start date
Marine Cpl
.577 Tyrannosaur.
Weren't they recently talking about replacing the M4 with a .308? Guess that project was scraped.
Anyway, a 6.8 isn't that much of an upgrade when using "Ball" rounds that don't expand to justify the cost of conversion. Especially when 77 gr MK 262's are available. The marginal increase at short range is just that. Marginal. At longer ranges past 300, the 77 grain actually drops less. It's not worth the cost or extra recoil. With the 77 grain, you have to change nothing.
@Podmonkey. Your up next.
Anyway, a 6.8 isn't that much of an upgrade when using "Ball" rounds that don't expand to justify the cost of conversion. Especially when 77 gr MK 262's are available. The marginal increase at short range is just that. Marginal. At longer ranges past 300, the 77 grain actually drops less. It's not worth the cost or extra recoil. With the 77 grain, you have to change nothing.
@Podmonkey. Your up next.
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The Army is working on a new cartridge but I doubt it's a 6.8. I hope whatever they do come up with is able to capably replace both the 5.56x45 and 7.62x51. I'd like to see the new cartridge as a 115gr 6mm bullet with a very high coefficient in a telescoped polymer case.
meketrefe
.450/400 Nitro Ex
The 6.8 can pump a 90-95gr solid / partition bullet to 2900fps.
These are more efficient in the air than the traditional lead core, and fmj heavier bullets.
They are also better penetrators.
But, again the answer is the 6mm. solid 80-90gr and 105gr for long range.
It could be the same case or some derivate of the current 223 case (like the 6x45) with 2 or 3 extra grains of powder.
Following the same directives as the 223 that have been proven to be very valid for many scenarios only increasing
range and momentum/lethality w/o giving up too much on weight, trajectory and firepower.
Again in most cases we don't need anything else than the 223 and if we do is going to have pretty similar directives.
There will never be a round that can take both roles of the 223 and 308. We can only hope for improvements on
those and 6mm and 7mm will give that respectively.
We don't have to invent anything. It is already invented. The chinese have gone 6mm for a reason.
If the 7.62x39 was a 6mm will probably be good for another 50 years.
These are more efficient in the air than the traditional lead core, and fmj heavier bullets.
They are also better penetrators.
But, again the answer is the 6mm. solid 80-90gr and 105gr for long range.
It could be the same case or some derivate of the current 223 case (like the 6x45) with 2 or 3 extra grains of powder.
Following the same directives as the 223 that have been proven to be very valid for many scenarios only increasing
range and momentum/lethality w/o giving up too much on weight, trajectory and firepower.
Again in most cases we don't need anything else than the 223 and if we do is going to have pretty similar directives.
There will never be a round that can take both roles of the 223 and 308. We can only hope for improvements on
those and 6mm and 7mm will give that respectively.
We don't have to invent anything. It is already invented. The chinese have gone 6mm for a reason.
If the 7.62x39 was a 6mm will probably be good for another 50 years.
meketrefe
.450/400 Nitro Ex
...to be clear, I said the 7mm due the bullets performance and in case some 6.5mm aficionado wonders
why not the 6.5 is because they max out at 140 grains and 120gr for solids. Not only that but a current 308,
yes the 308, with premium bullets and powders can replicate the trajectories and range of the best 6.5mm
cartridges and still one has a chamber that is the most popular in the world.
And with the solid core bullets one can go up to 160 - 165grs w/o maxing out that is plenty of momentum
for military use and in long range bullets can deliver 1,500-1,600 yards transonic range.
Same with the 7mm but better range.
And the bonus of longer barrel life.
why not the 6.5 is because they max out at 140 grains and 120gr for solids. Not only that but a current 308,
yes the 308, with premium bullets and powders can replicate the trajectories and range of the best 6.5mm
cartridges and still one has a chamber that is the most popular in the world.
And with the solid core bullets one can go up to 160 - 165grs w/o maxing out that is plenty of momentum
for military use and in long range bullets can deliver 1,500-1,600 yards transonic range.
Same with the 7mm but better range.
And the bonus of longer barrel life.
Bushmaster
.308 Win
IDK..? The 556 was used for accuracy and you could carry way more rounds with you.
Marine Cpl
.577 Tyrannosaur.
It's all semantics when ball rounds are being used. It's either going to pinhole if below the fragmentation threshold or fragment if the velocity is high enough. An extra .053 of an inch between .224 and .277 isn't going to make a difference on a human body.
Shadow2
6.5 Creedmoor
Your not comparing apples to apples ... copper solids out of a .308 will get you standard target ammo 6.5 results but the 6.5 will gain similar performance advantages from using the same type of copper solid bullets will stay supersonic 2000 yards. Do agree .308 barrel life is a bonus over 6.5. but the all things similar 6.5 still out performs.
oc shooter
.223 Rem
while I'm in favor of a new rifle and a new caliber and am truly a fan of the 6.5 creedmore I'm thinking the 308 is the way to go.
Marine Cpl
.577 Tyrannosaur.
The thing is that they already have the .308 for distance. That's what their crew served weapons fire. Snipers have it as well along with the even bigger .338 Lapua.
Those heavy calibers aren't suitable for close quarters and rapid fire on short and lightweight battle rifles.
Those heavy calibers aren't suitable for close quarters and rapid fire on short and lightweight battle rifles.
meketrefe
.450/400 Nitro Ex
Not really. the 6.5 solids max out at ~120gr to work with regular calibers and barrel twists. Anything longer will not work with a 8 twist barrel and typical casings. At the other hand 30 caliber and 7mm solids will work with the standard twists and will produced similar or better ballistics.
So while the best 6.5 solids might shoot slightly flatter they are not the greatest choice for any other than punching paper due to the lack of momentum
on the target. Still no better than the 7mm at anything other than a tad less recoil.
The best balance between trajectory and range+power will be put by the 7mm bullet in the 150gr-160gr range.
1st - 7mm, 150gr, 8-9 twist
2nd - 30 caliber, 160-180gr, 10 twist
3rd - 6.5mm, 120gr, 8 twist
4th - 6mm, 90gr, 8 twist
We are talking about the best most popular SA casings and w/o getting into exotic bullets, barrels and magnums.
Perhaps there is something I am missing in terms of new developments but IMO we are constricted by simple physics.
meketrefe
.450/400 Nitro Ex
Correct. They are either design to suppress including anti-material capability (Brick and mortar 308)
or in roles to reach where the regular infantry rifle cannot reach.
Shadow2
6.5 Creedmoor
Based on the description it sounds like they want an intermediate round which would be in the 100-120 ... 6-6.5 in a PPC sized case. the requirement they want that mystifies me is the ability to penetrate today's Armour ... can .308 with tungsten even do that never mind something smaller.
meketrefe
.450/400 Nitro Ex
The current M80A1 and MK319 will penetrate, same as the 5.56 based on the carbide hardened arrowhead from Liberty's ammunition original design.
Both impressive at low speeds in terms of wounding but with the edge to the M80A1 for barriers and armor. this a 3 part leadless bullet vs the MKs 2 part.