New Category of Rifle Closer to Reality

[Virdea]

For the past decade work on smart ammunition has progressed.  While most of the press went to chemical explosive weapons (a notable failure in the 20mm range but making progress in larger weapons) there has been quieter work on smart, man portable, kinetic energy weapons.

 

They won't replace the small calibre 6mm range rifles that arm most nations.  And there is absolutely no chance of making a 6mm range bullet smart in the next decade.  The new weapons are being tested in 11mm and higher calibers.  A successful test which made the popular press recently uses 12.7x99mm.

 

For years tests using bench arrangements have shown the smart bullets can correct for as much as 4 MOA error, but these tests were never real world, and duplication of effect was hard.  4 MOA is 100mm correction at 100 meters, and nearly 1 meter at a kilometer.  There is rumors - based on scientific papers, that more change of target can be garnered.

 

There are caveats.  The bullet design must be large enough to include the optical sensor in its tip.  These sensors are now tiny, but they still are as large as an entire 5.56x54 bullet and mass 2 grams or more.  Second, the vane rings on the bullet must be large enough that their bite is effective in moving the round.  The smallest that can be is around 11mm.  Finally the bullets really only work well at longer ranges.  Although change of angle is being used to express how well they work, in reality the figure is nonlinear and the bullets do not have much effect at shorter ranges.   

 

The most exciting aspect of the recent tests, buried in the popular hoopla, is that it took a series of lesser trained shooters and had them duplicating the shooting performance of skilled snipers at 800+ meters.  

 

There are two primary end users envisioned for the weapon.  The first is the sniper, who can use the bullet to overcome windage error - always the hardest thing to overcome.  The second though is the possibility of creating a new class of weapon for squad level use.  The weapon had play in the 70s called a "Light Assault Gun" - a modern day anti-tank rifle.  The new LAG would not have a rifled barrel, but would have smart sights - possibly helmet sights.  The operator would use direct fire on targets in the open 400m to 1600m as part of a team's bounding overwatch tactics.  The round could also be programmed in avoidance - meaning that team members would wear a device that would send out an RF signal.  Accidental shots at a team mate would cause the bullet to over-ride and miss.  

[Toxn]

Been following EXACTO, I take it?

[Sturgeon]

For the past decade work on smart ammunition has progressed.  While most of the press went to chemical explosive weapons (a notable failure in the 20mm range but making progress in larger weapons) there has been quieter work on smart, man portable, kinetic energy weapons.

 

They won't replace the small calibre 6mm range rifles that arm most nations.  And there is absolutely no chance of making a 6mm range bullet smart in the next decade.  The new weapons are being tested in 11mm and higher calibers.  A successful test which made the popular press recently uses 12.7x99mm.

 

For years tests using bench arrangements have shown the smart bullets can correct for as much as 4 MOA error, but these tests were never real world, and duplication of effect was hard.  4 MOA is 100mm correction at 100 meters, and nearly 1 meter at a kilometer.  There is rumors - based on scientific papers, that more change of target can be garnered.

 

There are caveats.  The bullet design must be large enough to include the optical sensor in its tip.  These sensors are now tiny, but they still are as large as an entire 5.56x54 bullet and mass 2 grams or more.  Second, the vane rings on the bullet must be large enough that their bite is effective in moving the round.  The smallest that can be is around 11mm.  Finally the bullets really only work well at longer ranges.  Although change of angle is being used to express how well they work, in reality the figure is nonlinear and the bullets do not have much effect at shorter ranges.   

 

The most exciting aspect of the recent tests, buried in the popular hoopla, is that it took a series of lesser trained shooters and had them duplicating the shooting performance of skilled snipers at 800+ meters.  

 

There are two primary end users envisioned for the weapon.  The first is the sniper, who can use the bullet to overcome windage error - always the hardest thing to overcome.  The second though is the possibility of creating a new class of weapon for squad level use.  The weapon had play in the 70s called a "Light Assault Gun" - a modern day anti-tank rifle.  The new LAG would not have a rifled barrel, but would have smart sights - possibly helmet sights.  The operator would use direct fire on targets in the open 400m to 1600m as part of a team's bounding overwatch tactics.  The round could also be programmed in avoidance - meaning that team members would wear a device that would send out an RF signal.  Accidental shots at a team mate would cause the bullet to over-ride and miss.  

 

I should think the best application of this would be to something that fired high explosive rounds. So maybe a cross between Tracking Point (sight), EXACTO (ammunition) and an M32 chassis.

[Xlucine]

What exactly would the LAG do that the sniper wouldn't? Is it something delivering worthwhile HE, or is it just a fancy ATR?

[Toxn]

30mm guided HEDP = win sauce

60mm guided mortar = even more win sauce

[Virdea]

Been following EXACTO, I take it?

 

 

For a couple of years, but I thought it was great CNN had a video story on it.  Not often obscure research projects get any air time at all.

[Virdea]

What exactly would the LAG do that the sniper wouldn't? Is it something delivering worthwhile HE, or is it just a fancy ATR?

 

The LAG reduces training time needed for sniping, making the task more accessible to wider deployment.  The French issued 1 sniper rifle per squad since the 1950s but their big problem has always been to find and train enough people to truly make that effective.  The physical envelope for a sniper is just too extreme for it to be common.  The LAG increases the physical envelope, meaning that precision weapons get more squad level air play and are more effective once they are in place.  

 

HE has been a problem for precision munitions because the most effective use of this technology is in a pretty fast moving projectile (unless you move to a finned projectile).  The little ridges that generate course changes need to be pretty large (again, bigger than 11mm) but also need hefty velocity to make useful changes - sort of like how slower planes need more wing to generate lift changes.  The difficulty with many tests is that the 20mm shell just does not provide enough HE space.  HE is an important answer to squad based firepower, but this technology may not be all that important to it - although I could see a fin controlled rifle grenade being a real winner using it.

[LostCosmonaut]

Something like a modernized M18 with guided rounds seems like it would be a good implementation of these ideas.

[Virdea]

I should think the best application of this would be to something that fired high explosive rounds. So maybe a cross between Tracking Point (sight), EXACTO (ammunition) and an M32 chassis.

 

The M32 is a hell of a weapon, but the 40mm may be ending its days and the Exacto may not be the right technology for it.  

 

Exacto uses distorting ridges to make course corrections.  The ridges are very small - with grooves not even a millimeter deep.  When they distort they need considerable negative air pressure behind them to cause a course correction - and that negative pressure comes from positive pressure on the leading edge of the ring.  To generate that pressure you need something like 600 meters per second at sea level on a 12.7mm round - a couple hundred meters per second on a 40mm round if it scales that well (has to be tested I am sure). There has been speculation that there is another control surface technology added to this based on very precise control of an offset wobble introduced into the ogive shape of a spinning bullet, but there is no literature on this - just some backroom talk that I myself was part of - and I always assume if I am involved in a conversation about military technology it cannot be really secret after all.  However in this case my idea of an unrifled sniper weapon goes away but the 40mm comes back - 40mm grenades spin.

 

The 40mm generates less than 80m/s at the muzzle, so it is not a candidate for this technology assuming these ridges are all that there is to correct with.  The limitation of the 40mm has been present for a number of years, and that is a spin-armed grenade is pretty accurate, but its accuracy cone is larger than the burst radius of the ammunition, and the form factor of the 40mm prevents higher velocities in shoulder weapons or smart accuracy because it has no effective control surfaces and does not generate enough velocity that any reasonable control surface could deploy.  Now a rifle grenade which has no form factor limitations could have big flip out wings.  The smart fuse that allows for corrections married to it would be effective.  An alternate might be a longer 40mm grenade that has some form of deployed bat wings.  

 

As Toxn says, a 30x173mm HEDP would be a terrifying weapon if it was fired even single shot using this technology.  Unstart's mention of the M18 might actually be a brilliant idea.  A big 57mm needs less velocity to effect changes, and that means it could be slower and even more accurate.  The big thing about the M18 was that it had nearly 1 kilograms of explosive in the HEAT design.  Disadvantage is that you loose the stealth provided by a traditional rifle.

[Virdea]

I have been trying to wrap my mind about smart munitions for a while, and I am taking another physics class from a friend at UTK next fall, but I understand that there are a limited number of ways to generate course correction in a moving object.  Airplanes generate course corrections by manipulating areas of low and high pressure around their wings - this is the most common way to do it.  In the Sioux City crash I interviewed aviation people (I was present on the ground for the crash) and those pilots generated course corrections by varying thrust on the engines - which apparently is really tough to do without a computer.

 

Computers allow all sorts of new thrust options - stealth planes are often unnatural shapes and reply on constant computer correction to leading edges to fly at all.  

 

The project I mention has two technology test beds coming together.  The first is how to make a bullet change directions.  The second is how to make a targeting system small enough to fit in a bullet.

 

 

[Sturgeon]

Virdea, you could use more conventional fins for 40mm grenades, I think. You might need something compatible with "long" 40mm rounds to accommodate the control surfaces, however.

Recoillesses are fine and dandy, but heavy. We have a lot of good explosive projectors organic to the platoon; I think we want better organic explosive projectors in the squad, hence my suggestion for the GL. 

[Virdea]

Virdea, you could use more conventional fins for 40mm grenades, I think. You might need something compatible with "long" 40mm rounds to accommodate the control surfaces, however.

Recoillesses are fine and dandy, but heavy. We have a lot of good explosive projectors organic to the platoon; I think we want better organic explosive projectors in the squad, hence my suggestion for the GL. 

 

 

I agree on the 40mm getting fins.  The long grenades could do it - with a small increase in propellant to keep your range.  The fins would spin deploy on the upward flight, then the smart nose would get its glimpse to the target.  Indirect fire means that the GL has to be smart as well as it have to tell the nose what the target looks like, but this is all easy.  

 

The weakness of the 40mm has been its miss circle, so anything that made it land closer to the intended target would get it back into the running.

 

The big advantage of the 40mm is that it might become universal.  Six guys lobbing grenades is going to be a lot of firepower if those grenades are landing within a meter of where they are aimed.

[Xlucine]

IMO drop the 40mm launcher altogether if you're doing that, and strap the guidance system to a ~50mm mortar. Like the french spigot thingy - it's already long enough for fins, and has better throw weight

[Virdea]

How about an AFG with the possibility of adding an AFRG or even AFPDG?

 

To work the 22mm grenade launcher point must be made smart and communicate with the sight, which has a digital alidade set up for 45 degree and 78 degree sighting (and could throw the grenade on a flat trajectory about 75 meters - any less and it won't arm anyway).

 

An AFG is an air foil grenade.  It is an offensive grenade with 350 grams of RDX, a smart ogive, fired by a bullet trap.  Blast radius is 10 meters.  Using the new head it has a circle of error at maximum distance of about 2 meters even in strong winds.  It also has the ability to enter windows and has enough maneuver potential to fly around a corner by sketching an arc to its target.

 

AFRG adds a small solid rocket motor - same as they make for toy rockets.  The rocket motor ignites about 40 meters out and adds to the accuracy and range of the munition, halving the error rate, flattening the trajectory or doubling the range.  The grenade is heavier though.

 

AFPDG is the weirdest one because it uses the smarts twice.  First it is fired at a 78 degree angle and lofts the grenade about 500 meters into the air.  In flight a drogue shoot deploys at the top of the ogive when velocity falls near zero - this is what happens with para flares that have no smarts.  The sight looks down, finds its target again, pops its drogue, and fires its rocket only after it enters a terminal dive.  Much more complicated and heavier, but has absolutely no way to be traced back to the firing unit when designed correctly.  

[Xlucine]

Ooh, I like those. The rocket assisted ones should let you reduce recoil as well.

[Collimatrix]

 

AFPDG is the weirdest one because it uses the smarts twice.  First it is fired at a 78 degree angle and lofts the grenade about 500 meters into the air.  In flight a drogue shoot deploys at the top of the ogive when velocity falls near zero - this is what happens with para flares that have no smarts.  The sight looks down, finds its target again, pops its drogue, and fires its rocket only after it enters a terminal dive.  Much more complicated and heavier, but has absolutely no way to be traced back to the firing unit when designed correctly.  

 

Actually, my thought when I saw this topic is that finally artillery has some way of firing shells on non-parabolic trajectories.  That ought to make counter-battery harder.

 

Additionally, as the number of control corrections per second, the reliability and precision of those inputs increases, it will eventually be possible to make unstable projectiles that are not spin-stabilized or fin-stabilizer.  There will be a corresponding increase in ballistic coefficients.

[Xlucine]

THE POWER OF INSTABILITY COMPELS YOU

[Virdea]

Unstable aerodynamic shares make stealth planes work, and unstable on one axis projectiles are much more maneuverable since their detent is to use all of their maneuver capacity to remain on steady course.  

 

As for cost, you are basically talking about launching an iWatch worth of gadgets attached to two model rocket engines and a rifle grenade.  The big cost is the sight, which is not expended.  

 

Now imagine 6 squad members firing grenades all at once.  Each grenade is smart, can self target, recognizes the human form and shape, can choose alternate targets, can disarm if its IFF detects danger close fire, and is stealthy because it is coming in from outside of threat axis.  That is the same as 21 M443 grenades except these land either where they are fired or can freelance.  Plus each of the riflemen can still engage with a full magazine for the mad minute suppression.

[Collimatrix]

Unstable aerodynamic shares make stealth planes work, and unstable on one axis projectiles are much more maneuverable since their detent is to use all of their maneuver capacity to remain on steady course.  

 

As for cost, you are basically talking about launching an iWatch worth of gadgets attached to two model rocket engines and a rifle grenade.  The big cost is the sight, which is not expended.  

 

Now imagine 6 squad members firing grenades all at once.  Each grenade is smart, can self target, recognizes the human form and shape, can choose alternate targets, can disarm if its IFF detects danger close fire, and is stealthy because it is coming in from outside of threat axis.  That is the same as 21 M443 grenades except these land either where they are fired or can freelance.  Plus each of the riflemen can still engage with a full magazine for the mad minute suppression.

 

Instability doesn't just make F-117s fly instead of lawn-darting, it makes planes better generally.

 

And if I had to guess, eventually Moore's Law is gonna get to the point where it's worth it to make bullets unstable.  No more fussy rifling, no more draggy fins.

 

You wouldn't even have to make the bullets guided or super-maneuverable.  The free (well, "free") reduction in drag would be plenty enough of a selling point.

 

As for what you're proposing with the grenades, that ain't too much more than sensor-fused munitions are already capable of.

[xthetenth]

That assumes Moore's Law holds up properly. Without some interesting transistor stuff, Dennard scaling has basically gone the way of the dodo, and that has dire ramifications for Moore's law. Intel 14 nm has been troubled as hell and TSMC 20 nm has been a soup sandwich that didn't result in a viable high performance node.

 

Cost per transistor has been up on recent nodes for crying out loud.

[Xlucine]

Intel sez they see moores law going down to 7nm, but after that all bets are off.

[Toxn]

I love that a simple observation made about changes in existing technology has been blown into this quasi-religious belief in ever-exponentiating computer power. 

 

And by "love" I mean hate.

[Sturgeon]

But it's Moore' LAW, Tox! You don't break laws!

[Virdea]

I love that a simple observation made about changes in existing technology has been blown into this quasi-religious belief in ever-exponentiating computer power. 

 

And by "love" I mean hate.

 

However, as theory goes, it has worked for now.  The trick is making it work when Kuhn raises his head and you have a paradigm shift.

 

And everyone knows what you get when you have two sets of paradigms.  40 cents.

[xthetenth]

Intel sez they see moores law going down to 7nm, but after that all bets are off.

 

Yeah, and Broadwell was a year late and produced chips that are basically mobile only SKUs except for specific Iris Pro ones that don't directly compete with the current lineup of Haswell/Devil's Canyon parts. Hopefully this gets sorted out with what I've heard of germanium technology getting thrown into the mix.