Build a new military cartridge

So, the 223 is too puny and the 30-06 and 308 are too big. Let’s start from scratch. The case has to be bigger than the 223, but not too big. Can’t be too short and fat, for MG feeding.

After some thought on this, I’d probably recommend a minor redesign on the 220 Swift case. Get rid of the semi-rim and some of the taper and expand it to 24 or 25 caliber and develop a military style bullet for it. It’s already a very strong case and once was a military round.

Sounds like a 243 would be a much simpler solution.

Already been solved. It is called the 6.5 Grendel. Fits in the current rifle, does more work.

I have to agree, even tho I use a 6.8, the Grendel will do just as well up close and much better way out there.

+2

We can do better than the Grendel.

Not fitting in the M-16, I don't think so.

Yes, if the military wants to go with all new rifles. But, it will be a hard sell to get them to go to an AR-10 platform for every pair of boots. Then you're back to the weight of a loaded mag. That's the reason they left the 7.62X51 in the first place. I did the math some months ago, and for a soldier or Marine to carry the same weight of ammo, but in 6.5 Grendel, he was carrying one more magazine and a total added weight of less than 2 pounds IIRC.

For it to fit in a mil spec M16/M4 the Grendal can be beat perhaps by some of its wildcats like the fat-rat, grendelmax or a few 6mm ones but the original Grendel was designed for the most performance to fit in an AR15 platforn . Bill A did pretty good with it.

With factory ammo the 123gr Grendel passes the 243 in energy around the 400 yard mark at 500 yards and beyond it easily surpasses the 243 in that measure. Give it a 108gr fmj shaped like the matchking of the same weight and run it at 2600+ from a M4 for a game changer in energy delivered on target compared to a 556.

Biggest issue imo is the military primarily dropping below a 16" in barrel length. That and bullet choice really affect the performance. If staying under 77gr a 6mm-223 would be my choice.

Question is then, why has the Grendal not been adopted by the military yet?

Longevity of parts. Bolts are the main concern.

Why are Snipers just now moving from the 7.62X51 to the 6.5 Creedmoor, after it's been in use for over a decade?

Bureaucratic red tape.

Certain units have been running 260 in their gas guns for a good while. While not big army they a lot of times get things rolling in the right direction.

Just been a couple of months anyone made an article of the move. Doesn't mean it didn't happen sooner.

Still, took em long enough!

Big army doesn't move fast at all.

On that note, does the military refer to it as 6.5 Creedmoor, or 6.5x71?

They don't need a new cartridge, just let them use the best bullets in the 5.56 & 7.62x51. If it's war, don't send them in with FMJ or OTMs designed to punch paper.

Several years ago, American Rifleman had an article "Taking back the half mile". The enemy figured out the 5.56mm was ineffective past 400 yards, so that's where they fought from. The article was revamping the "Designated Marksman" program. They brought M-14's out of storage and scoped them. Leaving one guy in the squad with the ability to engage the enemy farther out. Artillery and air support is not always available.

Give everyone a 6.5 Grendel and focus more on rifle training, and everyone would be better off. One day of education would go a long way.

I think a 110 Accubond would be perfect...if only Nosler made them. Minimum impact velocity for expansion is 1300 fps on the LRAB.

Can't use an expanding bullet in war.

The objective is to kill the most people and destroy the most property, but you can't use an expanding bullet in rifles.

That is the REAL problem. You can blow people with the grenades & missiles but you can't use an expanding bullet.

It's dumb.

What do we expect from politicians?

You're right, I forgot the Army likes that 14.5 inch (I think) barrel. Grendel would be handicapped.
Here we are discussing this (again), did the military say they wanted to replace the M4?

Unless you are not NATO...

People at war fighting for survival will shoot glass, nails, rocks, sharpened sticks and anything else they can stuff in the chamber.
I don't think it's because they can't read the rules.

Although I shoot a 6.8 at pigs hovering at around 100 yards, I'm thinking the 6.5 would be a better military round with the flatter trajectory at longer distances.

Forget I mentioned a redo of the 220 Swift case and neck up to 6.5mm or back to the original 6mm. I still think it would work great, and far better than the anemic Grendel, but my rethink draws me to the 30 Rem AR necked down to 6mm or 6.5mm.

Why are you reinventing the wheel?

"Anemic"? I've seen four rifles chambered in 6.5 Grendel ping every piece of steel on my range. All with 130 gr bullets.

Never have I seen a 5.56mm in an AR platform do it. Even though we tried. Anemic applies to the 5.56mm, look at how many hog hunters left it for the 6.5 Grendel or the 6.8 SPC.

Yes, I understand we are the only ones following the "rules".

Well, since Uncle Sam won’t listen to me, it doesn’t matter if I at least suggest a rethink of the military round. Still, there has to be a better one that could be developed. The 6.5CM got developed, to fill a niche. The 6.5 Grendel is an acceptable round, but where does it rank compared to the 6.5 Carcano round. I don’t have my loading books with me, but I expect the Carcano round is better. So is that progress? The Grendel just fits the on-hand hardware (AR15), and is apparently an improvement over the 223 in that rifle design.

What I don’t know is whether or not the 6.5-30 RemAR can be used in the AR15 platform.

Just thinking out load (sorta).

1. It has to fit in the M-16

2. What your new cartridge do that the 6.5 Grendel cannot?

Neck up a 224 Valkyrie to 6mm and give it a 1:7 twist and call it the 6mm NATO. Shoot 95-105 high BC OTMs.

The 30 Rem AR will push a 130 gr bullet to 2800, which is 400 or more FPS faster than the Grendel and the Soviet era case the Grendel is based on. Neck that 30 AR to 6.5, and you’d have a serious cartridge right there with the 260 or 6.5CM, with the same steel banging capabilities.

I don’t know if it would be workable in the AR15 platform. the case head is not small.

Case length, plus bullet length, is the big question.

The R15 is a proprietary rifle with the 30AR cartridge, it is not mill spec so it would be full replacement not say BCG, Barrel and Mag like the Grendel would be for he existing M4 or M16 arms.

Interesting about the 30AR which is a neat cartridge for sure but the overall case length and bullet ogive lengths do not really play into being able to use high BC bullets for the range 400 to 600 yards to extend the useful range of the infantryman. With teh Grendel you have a very comparable trajectory out to 400 yards then a little better with more energy from 400 to 600 or more yards than with the 30AR. The one

30AR link

In Remington fashion the velocities given are from a 24 inch barrel even though the R15 has a 22 inch barrel. BC of the 125gr bullets is given as .267 and a 123gr Hornady 6.5 bullet has a realistic BC of .490.

No doubt the 30AR is a fine hunting round at ranges most of us should be shooting but if carrying one or the other in the Military I will take the Grendel. More rounds in a mag, better ballistics at distance where the 223 is said to be ineffective (though I do not want to be hit with a bullet from one at any distance).

Dig into bill Alexanders information about the Grendel it presented several challenges bullet length for the round to have a somewhat high BC but still fit in the magazine. The Grendel I think has more in common with the PPC line of cartridges than the 7.62X39. It is basically the 6mmPPC with the shoulder pushed forward a little for more case capacity and necked up to 6.5mm. Interesting that lapua had some voice in that choice and made the first brass for teh 6.5 Grendel. Easy for them to do since they also make 220 russian brass which many shooters used to get their PPC brass.

For the record, I was suggesting necking the 30AR to 6.5, therefore the same bullet in competing calibers.

Also note that case length of Grendel and 30AR are the same (0.01 diff) and COAL are the same. 30AR case head is bigger.

As for having to change or modify the M16 platform itself, that will happen eventually anyway. Why wait? It isn’t like the M16/M4 is perfect. It’s just what we have at present.

Maybe it’s just me, but I can’t see what’s special about a round that pushes a 130 gr bullet to 2400 FPS. Surely there’s a better option, and I’m just using the idea of a necked down 30AR as one option.

I thought the military solved this already with their new M855A1 bullet. Supposed to be lethal to 600 yards.


https://usarmorment.com/pdf/M855A1.pdf

I wouldn't say "solved", more like a stop gap measure.

I read all I could find on the M855A1 some time back. Supposedly it is pretty rough on the M4s and reduces reliability somewhat. At that time I tried to find out what pressure it's loaded to, and one data sheet or article listed it as CLASSIFIED.

I'd bet on it being dropped at some point.

I can't see how it's not going to be harsh. Longer bullet seated deeper and going faster than previous green tip ammo.

They should have just adopted the MK318 Mod 0 that the Marines originally adopted which was a simple design that solved all the problems.

I'm not ready to buy into the figure given in this article until I see a US military document, but it could be correct. If so, then things have changed dramatically. The article gives insight to dealing with pressure and gas problems.

http://www.gunsandammo.com/rifles/surefire-optimized-bolt-carrier-assembly/

River rider, that was interesting reading. When I started this discussion, which is about the same as plenty of previous discussions, my main interest was in what you knowledgeable fellows thought would be a good replacement round for the AR. It seems obvious that even Uncle Sam thinks the 223 round isn’t ‘enough gun’. Combine that with the likelihood that caseless ammo isn’t something for this lifetime, what will be the next move. Rather than totally replacing the rifle platform, changing the cartridge seems more likely. And that’s why I suggested the 30AR necked to 6.5mm. But the real answer is probably going to be a cartridge that doesn’t presently exist. Something designed from scratch to fit the platform and the magazines, with a bullet weight of 100 to 120 grains and a mv of about 2800 FPS. Probably 24 or 25 caliber.

I agree...it seems obvious that the military is not satisfied with the 5.56 round. On the other hand, I think the 6.5 Grendel has a lot to offer. I'm not really sure though, because we shooters don't usually mess with FMJs in the Grendel. I know there are objections to sporting bullets in military application, but I still think something like a 110-grain LRAB would be formidable.

123 SMK, G-1 .510 in a 6.5 Grendel. The military has been launching SMKs down range for decades. This is just another one.

https://www.sierrabullets.com/store/product.cfm/sn/1727/264-dia-65mm-123-gr-HPBT

This was one of the more interesting threads. I like when you guys nerd out on a topics similar to this.

It's all for fun, the military will not change from the 5.56 or 7.62x51. All the money is going to the Space Force.

The Space Force will shoot .45-70s. BC won't matter where they're gonna be.

Very true. It will take long range shooting to a whole new level.

Well, I hear you guys on the Grendel, but I still don’t consider it the answer for 223 replacement. The biggest thing going for it is that it fits in the existing platform. But, 2400 FPS mv isn’t good enough.

Maybe it would be best to just issue the newer lighter AR10’s, or revamp the AR15 platform to handle a serious cartridge smaller than the 6.5 CM and larger than the 223. And that’s what got me to thinking about something like the 30AR necked down to 24 or 25 caliber and a 100 gr bullet. Now that sounds reasonable to me. MV should be 2800+.

The 30AR case is the same size as the Grendel case. If you like the Grendel, why can’t we like the necked down 30AR?

Actually, the military has already started to make the change from 7.62 as mentioned earlier in this thread. Moving to 6.5CM

The future is Lasers.

scottfromdallas, exactly how far in the future are you thinking? I bet there will be plenty of time to switch to a different cartridge and get lots of use out of it long before the Laser weapon phases out smokeless powder...that is IF the laser weapon ever phases out smokeless powder.

I don't think it's that far off. It might already be happening on ships and vehicles. Lasers are cheaper to fire than missiles.