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Army chooses Sig Sauer to build Next Generation Squad Weapon.
- Thread starter Dr_Scholl
- Start date
Yeah. I think the bi-metal cases could have A LOT of promise for something like the 6 ARC. 80k psi in SBR length barrels like 12.5”, could be a seriously nifty carbine. It would just need a strengthened bolt. And it would really shine I bet in 16-18” barrels.
38ExtraSpecial
NES Member
I don’t think we would have lost any innovation. No metal cases and “caseless” ammo has been in the works for a long time. Same for new platforms. They would have been working on them. There are tons of platforms touted to be better than the AR but what will GOV do about it?
Agreed that it doesn’t have to be another 2.5# but what we think and what the government accepted are 2 different things. Look at the new SFAR offering with AR10 performance in AR15 size. Easy way to beef up the bolt and keep a lighter platform. Enjoying the benefits of strength and light weight and allowing for more cartridge choices.
I think the blackout doesn’t get as much respect as it deserves. For an intermediate cartridge it’s great and it doesn’t lose much to the 7.62x39 which everyone seems to love.
Depending on the scenario and distances I would think the 300 BO would be better. Jungles? Dense forest ? 150 yards and less? Would that blackout be the favorite over the 5.56?
38ExtraSpecial
NES Member
I’m what capacity? New semi auto Platforms or bolt guns? LMG?
I would say just make sure to use the 108s and input that it is a gas gun if you can. I don't use quickload so I don't know how nitty gritty you can get with it. But the lighter bullets will do higher velocity, obviously. The problem is they don't have the high BC that the longer and heavier bullets do like those in the 108 grain range. And it is that high BC with the heavier bullets at longer barrel bolt gun velocities that gets the 6mm ARC to shoot so flat. Take out one of those variables, and it doesn't have quite the allure to it.
Probably gas guns (maybe just SDM type role), and LMGs. I doubt it will catch on with bolt guns since they can easily operate long action cartridges with more oomph.
Though I think the case technology will proliferate to other calibers in a few years.
38ExtraSpecial
NES Member
I think there’s an option there for that. Or I can tweak a little and figure a couple inches less barrel some thing. Make some comparisons to known data and see how it looks.
Again it comes down to can it out perform what we have?
108 at 2600 fps
Zero at 200 has 50” drop at 500 and 790 ft/lb retained energy
55 grain at 3150 fps
Zero at 200 has 51” drop at 500 and only 255 ft/lb retained energy
So the ARC would do much better
Ha, I don’t love 7.62x39.
But really, 300blk does great for certain things. Subgun replacement, or lightweight hunting medium sized game at short distances.
But in a standard military carbine, its max point blank range is just too short. Your average soldier sucks at estimating range and can’t work out drops to save their lives. Most don’t even fully understand the concept of bullet trajectory.
A 6mm cartridge in an AR15 platform at 80K PSI would be an incredible combination. I would love to see that happen.
Where I'm torn with 6mm is that in the AR15 platform it doesn't do anything special until you get that barrel length out to 22" or so. And even then its only marginally better than the 6.5 grendel. But if put the 6mm ARC in a bolt gun and crank up the pressure to what it can tolerate, now it starts to come alive. But then you have to ask yourself, why am I limiting myself to a 6mm bullet in a cartridge designed for magazine length in the AR15? Why wouldn't I shoot a 6mm bullet from a longer cartridge that i can stuff more powder in if I am using a bolt gun that isn't limited to an AR15 mag length?
So, 6mm ARC is kind of cool for me, but also it kind of misses a lot of marks. And I think the hype around it is generally misleading.
38ExtraSpecial
NES Member
Not really. A 6.5 creedmoor running a 140 at 2650 out of a 16.5” leave you with 48” drop and 1100 energy at 500 with the same metrics as above
The 6.8 runs 44” drop and 1130 energy
It’s not that far off. That’s adjusting for the short barrel velocity from the 6.5 vs. the standard length.
Even if you had to shave off a little more velocity for a gas gun you’re still close to neck and neck with a standard construction cartridge at standard pressures.
38ExtraSpecial
NES Member
Much better than the 5.56, yes. But the 6.5 grendel didn't replace the 5.56 for a lot of reasons. And the 6mm ARC isn't measurably better than that.
Also, I think the 2600 fps number is a little high. From what I've seen with an 18" barrel the average velocity with the 108 ELDMs is in the low to mid 2500s. And thats a nice cartridge with a really good BC.
38ExtraSpecial
NES Member
I had another thread on this a ways back about if you knew then what you knew now would you have chambered the AR in a different cartridge. It turned into a shit storm.
I think a lot of reasons we don’t change is because the GOV is ok with how things are going. Do they want new manuals? Train the trainers? New weapons and accessories? Increase in costs for retooling for more expensive ammo? I would imagine Lake City would need to spend some $$ to make 6ARC in the quantity they would need.
Not that they care about spending our tax dollars There’s something in all of that process that holds them back.
We’ve seen out military outgunned over the years because we didn’t want to upgrade or we chose a cheaper weapon to manufacture. Or because we thought we could stay with single shots for a while longer.
All good points. And the other thing is people like you and I love to imagine what the best of the best would be. And we can go out and buy one of whatever those are for us. But the .gov is more looking at it like is what we have good enough? Is there a need that it is not meeting where we have to go out and retool and invest all of this time and money and resources into something that may not even pan out for a number of reasons? The 5.56 has been good enough for a very long time. Might not be what we would pick out of the gate. But good enough for the widest range of soldiers in the widest range of operations. Now that there are concerns about the opposition wearing body armor and able to engage us at longer distances, there may be a case to be made to look into whether the 5.56 is good enough for that.I had another thread on this a ways back about if you knew then what you knew now would you have chambered the AR in a different cartridge. It turned into a shit storm.
I think a lot of reasons we don’t change is because the GOV is ok with how things are going. Do they want new manuals? Train the trainers? New weapons and accessories? Increase in costs for retooling for more expensive ammo? I would imagine Lake City would need to spend some $$ to make 6ARC in the quantity they would need.
Not that they care about spending our tax dollars There’s something in all of that process that holds them back.
We’ve seen out military outgunned over the years because we didn’t want to upgrade or we chose a cheaper weapon to manufacture. Or because we thought we could stay with single shots for a while longer.
I guess the M-16 platform was getting to inexpensive so they had to find another way to blow some cash. How about replacing our aging Apache helicopters that have so much slop in the guns they can no longer shoot straight.... Nah....
38ExtraSpecial
NES Member
Well said.
We can debate numbers and have fun all day long but we’re not calling the shots.
It’s the gun industry that tells us we need more and bigger and better and faster and flatter but really the 30-30 can do just about all the hunting we need. Same for 5.56 for military no doubt.
I’ve said it before I’m the last one to rag on gun companies for weird stuff like the 30 Super Carry. I love to see innovation.
This industry is make up of little changes and nitpicking which results in wins and losses and is why the 45-70 is still around and the 40 is dying off.
It’s just fun to guess and debate where things will go.
![[rofl]](/xen/styles/default/xenforo/smilies.vb/013.gif "ROFL [rofl]")
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Has anyone considered how a fat casing necked down to accommodate a 6mm is going to feed? In a select-fire carbine? In a SAW? It'll work just fine in a bolt gun, but I don't envy the engineer that needs to design a weapon with a high rate of fire that reliably feeds these cartridges. The military cartridges look the way they do for a reason. Especially the funky-looking 7.62x39 and 5.45x39. They usually feed and extract, reliably even in a weapon that hasn't been cleaned since it left the factory.
I don't think that any cartridge that looks anything like 6mm ARC or 6.5 Grendel is going to work well in a select-fire weapon with a high rate of fire, that will be used in combat. Which usually means exposure to dirt, dust, grime and abuse. I doubt that it will feed and extract reliably in these conditions.
I have no idea. That is a good point. And you've made me curious about it. I would love to know how the testing is going with these cartridges as far as automatic fire is concerned, and what issues and solutions they are working through.
Mesatchornug
NES Member
Russian ammo has significant taper because they use steel cases and it aids extraction. Brass is more lubricious.
We tend to prefer steeper cartridge walls, and seem to manage just fine. There are plenty of self-loading rifles in these newer cartridges. The difference is probably relatively small.
That isn't to say it's impossible that Sig has screwed up here, but this (and case head separation) fall way below weight and barrel life as areas of concern in my mind.
Cap'n Mike
NES Member
This seems like the key lines in the Army Times Article.
By either halfling the basic ammo load or doubling the weight of it with this new cartridge, not to mention grossly increasing the weight of the rifle itself, this program is doomed to fail imho.
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Most modern Russian military ammo is either lacquered steel case or "bi-metal". The latter is essentially a sheet of steel hot-rolled together with a sheet of Copper-Zinc alloy (90% Copper 10% Zinc). The two sheets are bonded together permanently and become one. The outer layer is copper-zinc, not any less lubricious than brass. Lacquered steel case is mostly AK and machine gun ammo, because it costs less than the bi-metal and AK will eat it just fine and ask for more. Tapered case certainly helped the Russkies to get away with lacquered steel case. It's very dirty, but the AK doesn't seem to care.
There is a big difference between the performance requirements of a civilian AR-15 carbine that gets taken to the range once in a while and a SAW or an army rifle, which are meant, among other things, to lay suppressive fire. Which means going full-auto with a high rate of fire. While these newer cartridges often offer better accuracy than the traditional designs, feeding and extraction is more problematic, especially in select-fire weapons with high rate of fire. It's a well known fact in firearms design. If you want the cartridge to feed reliably at high rate of fire, it needs to be "smooth". If you want reliable extraction of dirty steel-case ammo from a filthy chamber, you want a tapered case. Which is why Russians do it this way.
From the engineering standpoint mating the steel and brass reliably is a solvable problem. Just heat them to the right temp and roll them together. With some alloys you may ever get away with doing it cold. My main concern would be cost. If you plan on going to war, you want your ammo cheap to make, so that you can make a lot of it. 80K PSI is a lot of pressure though, so you'd need to find steel that can withstand it, yet to be ductile enough to cold-work a coin-shaped flat blank into a case. These two requirements conflict with each other, so it's not easy. I am sure that alloys that do the job exist, but the price may be an issue.
the sand particle in the barrel that leads to a brass being torn apart in a gunfight will make you dead right there, if your gun is stuck and stops firing.
weight and accuracy of the said gun at 50 yds engagement distance - matters almost none.
i really cannot think of any existing design out there for the case to be made with a seam in it. the wall and the base were always made from a single metal piece, for a reason. dunno, just sounds crazy odd to me.
Mesatchornug
NES Member
For weight, I'm thinking more about the limits is places on an individual. There's necessarily a limit to how much we can make someone carry. I'm sure they continually push that number upward. Whatever number they go by - every ounce we add to the gun is an ounce we've taken away from ammo, armor, communication gear, etc.
Cap'n Mike
NES Member
There is an old sayin, An Infantryman will always carry 100 pounds of the lightest gear technology can devise.
38ExtraSpecial
NES Member
I was adjusting for a shorter barrel, to make it apples to apples with the Sig
if the goal now is to make a solution to penetrate through lev4 armor plates, then, well, sexy compact short barreled guns that were created to mostly shoot down unarmed civilians in urban setups are not truly adequate no more.
when it progresses into a real conflict, you'll see how somehow the big ass 7.62x54 machine guns come back with those black tipped sexy bullets - chechens really loved posing with those.
16”?
My 16” shoots 143gr ELD-X at 2550.
Yeah, but that’s a 16” 6.5CM vs a 13” 6.8. Make a 16” SDM-R variant and you’ve got another thing all together. Don’t get me wrong, a 16” 6.5 CM with a good “A1” style bullet, in a light-ish weight rifle would have been a fantastic stop-gap. Especially if they could have funded the bi-metal case research separately from the XM5 program. But I’m not upset with the R&D overall. If the M7 sucks, it will be short lived.
