The Future of Small Arms

[Todg]

Proposed: The COTI Advanced Combat Rifle

Based in the discussion to date, and input from all the posters, here's a first pass weapon that could be built at current technology. The only assumption made is that flechettes can be manufactured to perform in a suitably lethal manner.

The COTI ACR is designed to be the preeminent point target infantry weapon. It uses technology derived from a number of sources, most notably th HK G11. Weights are estimated base on the actual weapons.

The ACR is a bullpup layout 'rifle' ustilizing a modified form of the HK G11 action enlarged to accept encapsulated flechette ammunition. The flechette is held by a puller type sabot and the propellant surrounds the flechette body. On firing, the priming compaound pulverizes and ignites the solid propellant charge, and drives the flechette/sabot down a 20 inch smooth bore barrel (rifling being unnecessary thanks to fin stabilization). The sabot is stripped at the muzzle, with the flechette reaching a nominal muzzle velocity of not less than 1500 meters per second. This round require no change in sighting over combat range and is able to penetrate all know body armor.

The normal method of oeration is a 5 round burst, delivered at a cyclic rate of 2000 round per minute. With a total weapon weight (unloaded) of 7 pounds, the five round burst generates approximately the same recoil as a single round of 5.56x54mm amunition fired from and M16.

Ammunition is fed into the weapon from a 100 round ammunition 'casette' inserted into the weapon from the front, parallel to and above the handguard. The magazine port is funneled to allow for easy insertion and the magazine is automatically ejected after the last round is fired. The magazine can be changed easily with the off hand without requiring the soldier to shift position or remove his firing hand from the grip. The magazine also acts as a sighting plane extending in front of the electronic sight.

The sight itself is a simple holographic, 5 MOA dot. Brightness is automatically adjusted based on the ambient light. The sighting reticle is normally steady on, but flashes when there are 3 bursts (15 rounds) remaining in the magazine.

The safety extends into the triggerguard in the manner of the M-14 and prevents the firer from insering his finger in the trigger with the safety on.

The basic weapon is built around an alloy chassis sytem to which all componant parts are attached. The chassis features picatinny types rails at multiple locations. This makes it relatively simple to add accessories or sighting devices to the platform. All parts are built as subassemblies that are not intended to be further disassembled. The action is gas operated via short stroke piston and is designed to minimize the intrsusion of foreign material into the action.

The weapon is designed to be particularly ergonomic, and length of pull and basic fit of the weapon can be modified due to it's modular construction.

The basic components are either precision stamping or machined castings that are optimized for ease of production. The outer case is high impact carbonfiber impregnated polymer.

The only controls on the weapon are the safety and trigger and charging handle. The sight activates automatically when the dust covers are opened.

The only opening on the weapon is the muzzle and a (normally sealed) unloading port in the event of a misfire, or to unload alive round.

Mass approx 3.5 Kilos, length approx 750mm
Manufactured at TL 8, Cr500

 

[kaladorn]

Originally posted by Uncle Bob:
The warhead of a 40x46SR is very short, almost spherical. The 25mm has a longer, more streamlined warhead that weighs a little less (IIRC, 90 g vs 110 g). A lot of the mass in the 40x46SR is a rather inneficient mechanical fuse so the 25mm with electronic fuse has a bigger bang.

Being more streamlined helps, but I doubt the max range will go much over 500m (vs 800m? with the 20mm).

What's wrong with making a better fused more streamlined 40mm?

I'm saying if you compare two identical tech rounds where the only difference is size, you gotta know which one will be more dangerous.

Now, range is a good point. But am I gonna be lobbing rifle shots at something 800m away? Jeez, I have to admit I have troubles out at 500m. 800? Holy smokes. (Without optics)

You misunderstand me. My point was that for a century the US Army has defined the "effective range" of rifles not by the weapon's accuracy or ballisticss but by the fire control. And that fire control is the "mark I eyeball" backed up by the skill of the soldier.

Ah. Okay, but the eyesight itself isn't the issue. Unless of course, you are me

Ah, but at range the bullet drops and the dot doesn't. Unless you rig a laser rangefinder to move the dot to compensate, at which point the fire control again defines the weapon.

The bullet drop is irrelevant, since the dot, placed by a beam, also ranged the shot, aligned the firing mechanism accordingly, and scattered the burst neatly around that point....

And yes, that is fire control

 

[kaladorn]

Originally posted by Corejob:
Ever looked at a laser with STANO gear? You can see the beam rather clearly. If you use a laser pointer, the bad guys will be able to trace the line right back to you.

Sure, but in theory the same is true with any non-passive ranging, be it RF, Radar, Ultrasonic, Laser, X-Laser, Lidar, Maser, etc.

But if you want accurate ranging[1], that'll probably have to be the case.

[1] Unless portable and effective AI vision systems which can effectively estimate from parallax etc. on objects of unknown dimension can be created and made portable on the weapon. I don't see this as likely anytime soon.

 

[kaladorn]

Originally posted by Corejob:

There remains a concern about magzine changes with bullpup rifles, but this could be addressed either by using some kind of 'ammunition casette' to make changes less frequently required, or by using an alternate feed system like that of the G11 that allows the soldier to reload without awkward manipulations of the weapon.

What about a dual mag system and the mechanical/control systems to switch out... thus perhaps you can reload while still being ready to fire if need be... (A is empty, gun switches to B... you take your off hand and pop the release for A and work a new mag in, but you've never got the issue of not having a finger on the trigger and round up the spout).

over the same ranges. It's main disadvantage is that it is long, requiring a suitably long cartridge.

Not very good for PDW's, through-the-handle mags, or sidearms. (Gauss pistols are interesting... try to get a 40mm long projectile into the pistol grip... you certainly won't be getting a 60mm one in.... or 80mm. So the ability to use large caliber gauss weapons in sidearms is minimal.

 

[kaladorn]

TL-9 ACR.... sounds interesting, though I'm not sure why you'd want that sort of safety (never had problems with the normal kind).

Also, might this not have 'design issues' around the sabot stripping, especially in really crappy conditions like sand, etc.

Where's my picture? <*kidding*>

 

[Anthony]

Originally posted by kaladorn:
What's wrong with making a better fused more streamlined 40mm?

Well, the obvious way to streamline a 40mm projectile is to take the same projectile weight and put it in a narrower, longer projectile -- say, rather than 40x46, 30x80 or 25x116.

What they actually did was combine a narrower, longer projectile with an actually smaller projectile, perhaps on the theory that if the current 40mm is good enough, it's better to make the new round lighter rather than more powerful.

 

[Uncle Bob]

Problem with flechettes in Traveller is that they are not stable in vaccuum or thin atmosphere, so spin-stabilized APDS may be more common.

 

[Todg]

Originally posted by kaladorn:
[QB] Sure, but in theory the same is true with any non-passive ranging, be it RF, Radar, Ultrasonic, Laser, X-Laser, Lidar, Maser, etc.

But if you want accurate ranging[1], that'll probably have to be the case.

[1] Unless portable and effective AI vision systems which can effectively estimate from parallax etc. on objects of unknown dimension can be created and made portable on the weapon. I don't see this as likely anytime soon.

If you use a suitably high velocity projectile, like the flechette, the drop is negligable over combat ranges and so ranging is not an issue.

And there are optical ranging methods that don't rely on active sensors, they just aren't a simle to make. Image coincidence was widely used in the days before laser range finders and could be automated without major difficulties - they's just be more complex. You can also range via known object size, which works fairly well - consider the ART scope - but i'm not sure of it could be automated.

It seems simpler to just not have to deal with it. Besides, high velocity projectiles also minimize the effects of wind drift, something no sighting system will be able to do well.

 

[Todg]

Originally posted by kaladorn:
What about a dual mag system and the mechanical/control systems to switch out... thus perhaps you can reload while still being ready to fire if need be... (A is empty, gun switches to B... you take your off hand and pop the release for A and work a new mag in, but you've never got the issue of not having a finger on the trigger and round up the spout).

I consiodered the concept of a 'self consuming' magazine, where cartridges are somehow helt together in a brick, and then separated as they are fed into the weapon. You could contsantly feed in new ammunition without ever removing the clip (something like having belt feed and always adding more loinked ammo to the belt in the weapon as it is consumed). I just haven't figured out how to do it.

One of the features of the WWII Johnson rifles, with it's internal 10 round rotary magazine, was that you could top it off through a port without having the weapon be out of service.

Anyone got ideas?

Not very good for PDW's, through-the-handle mags, or sidearms. (Gauss pistols are interesting... try to get a 40mm long projectile into the pistol grip... you certainly won't be getting a 60mm one in.... or 80mm. So the ability to use large caliber gauss weapons in sidearms is minimal. [/QUOTE]

Well, I've never been keen on the idea od PDWs. I persobally think it is a solution to a non-existant problem. And pistols have been relatively meaningless weapon for combat operations for about a century. They're primarily badges of rank of emergency arms when anything is better than nothing.

 

[Todg]

Originally posted by kaladorn:
TL-9 ACR.... sounds interesting, though I'm not sure why you'd want that sort of safety (never had problems with the normal kind).

I thought I put the TL at 8. It's certainly doable right now. As for the safety, it's simple, ambidextrous and 'ergonomic'. You don't have to learn it - if the trigger is blocked, the safety is on. You can remove the safety by putting you finger into the trigger guard and are instantly ready to shoot.

I've never had problems either, but then we've learned to find the safety. The above is a system that extremely obvious, even to someone who's not handled a weapon before.

I've always admired the simplicity of this system, the same way I like the fact that on the K-98, when the weapon is on safe, the safety tab blocks the shooters line of sight. Simple, elegant and effective.

Also, might this not have 'design issues' around the sabot stripping, especially in really crappy conditions like sand, etc.

Technically, the sabot is going to be stripped by air resistance. This is not a problem, as it is a very mature technology.

Where's my picture? <*kidding*>

Let me see what I can come up with.

 

[Todg]

Originally posted by Uncle Bob:
Problem with flechettes in Traveller is that they are not stable in vaccuum or thin atmosphere, so spin-stabilized APDS may be more common.

That is very true.

However, I expect that most combat operations are going to happen in places that people want. For 'Protected Forces' troops, there's going to be a lot of specialized gear, even special weapons. The intent was not to design a perfect rifle for every concievable situation, but rather one that works well for most environments. After all, we don't expect Navy SEALS to be able to fire their standard weapons while underwater.

If you wanted to give the flechette rifle some untility in vaccum, you just add very slow twist rifling - enough to stabilize the projectil in vaccum or trace atmosphere, but not enough to cause problems in normal environments.

 

[Badbru]

ahhh one of my favourite topics as a Traveller Ref, designing small arms. Corejobs nice description of the COTI TL8 ACR got me to get FF&S out. So for those that might be interested in an attempt at the COTI TL8 ACR for GDW TNE here's mine:
The Round: 6mm x 30mm Necked Caseless Discarding
Sabot (described as a Flechette I spent an hour on multi projectiles befor re reading corejobs post where he describes the round as "the" flechette in sabot form so I reverted to simple FF&S "DS") Ave Energy 1493-J 8.5grams Average Barrel lenght 41.5cm

The Weapon: Actual barrel lenght 50cm (20inches approx) Standard book weights for a light barrel would put this at 1kg costing 200crs. I frequently incorporate the Table of Materials for Construction though, where we see TL8 has composite laminates as new tech which when compared to Hard steel is 3 x tougher for the same weight or one third the weight for the same toughness. When I incorporate this I usually only apply it to half the book determined weight. Therefor the Barrel could be as low as 0.33kg or more likely 0.4 kg Actual muzzle energy is then determined using FF&S formulae to be 1642-J resulting in a Damage of 3 dice and a penetration for DS of 1-2-Nil meaning dice lost per armour value (first number corresponds to both close and medium range)At TL8 the only armour available is Flak jackets AV 1 Ballistic Cloth AV 1 and Ballistic weave AV 1. Home brew additions might include av 1 plate inserts upping your AV to 2 but this round will still penetrate that albeit only with one dice at both close and medium. Light self loading reciever ROF codes SA and 5 17.4cm 1.493kg 373crs (again this could be 66.6% lighter with composite laminate construction. Though I'd probably just reduce it to 1kg.) Bullpup stock 5cm 0.1kg 10crs
100 round capacity box magazines 0.53kg empty 1.38kg loaded TL8 optic sights (sorry Corejob holographics aren't available till TL13+)0.1kg 150crs range modifier x 1.1 Regular Flash suppressor combined with long mussle break 8cm 0.45kg 205crs Recoil mod (rcm 0.65)Shock Absorber modifications to stock 0.2kg 75crs rcm 0.9 Auto action rcm 0.95 total rcm 0.55575
Ball unrounded short range 54.5 m x DS value 1.2
65.4m round to 65m x optic sight value 1.1 70m short range, 140m medium 280m long 560m extreem.
Loaded weapon weight (as book formulae) 4.723kg.You could easily loose almost 1kg or more of this through composite laminate construction IMHO. Single shot recoil = 1.27 rounded to 1
Burst recoil = 3.177 rounded to 3.

TL .Cal ROF Dam Pen Bulk Mag SS Brst Shrt wt price
8..6x30..5...3..1-2-N...5...100...1....3......70.(4.7kg).1013crs

Weapon could come to your requested 3.5kg but not your 500 crs
I'm not sure how many meters per second 1642-Joules muzzle energy is nor is the Rate of Fire 2000/minute but it does fire 5 round bursts.
It's not what I'd call a "manstopper" nor is it a massive improvement over the RCEG's 5mm Assault rifle firing TL8 DS ammo

7...5x50..5...3..1-2-N..7...30...2....6..60 3.95 737crs

I hope someone can use it and I hope I've not just violated anyones copywrited material. Flame away

 

[Straybow]

Originally posted by Corejob:
Ammunition is fed into the weapon from a 100 round ammunition 'casette' inserted into the weapon from the front, parallel to and above the handguard. The magazine port is funneled to allow for easy insertion and the magazine is automatically ejected after the last round is fired. The magazine can be changed easily with the off hand without requiring the soldier to shift position or remove his firing hand from the grip. The magazine also acts as a sighting plane extending in front of the electronic sight.

I'm having difficulty imagining what that last sentence means. The cassette is above the barrel in front of the grip, with the ammo somehow passed back to the chamber, perhaps ¼ the length of the weapon?

I also don't like the cassette ejecting automatically. In WWII the M-1 clip holder would eject after the last round was fired, and the enemy learned to recognize the "ping" that meant "I'm reloading now, gimme a few seconds."

Granted with 20 bursts that comes up less frequently. I already get a signal when I'm down to 3 remaining, and presumably a signal indicating no ammo present. Autoeject is handy if I'm really, really pressed, and I've already got the next cassette in my other hand, but otherwise I'd rather press a button to eject the cassette when *I* am good and ready to load a new cassette.

There has to be a manual cassette release anyway, just as there has to be a port for ejecting misfires and chambered rounds, so it doesn't change the design.

Next question, why 5 round bursts? Did somebody point to data on the optimum burst size that I missed? I know 3 is the burst used for most military guns because of recoil and cyclic rate, but the G11 also used 3 despite low recoil and 2000rpm rate.

3 doesn't divide evenly into the 100rd cassette, but 4 does&#133

 

[kaladorn]

Originally posted by Uncle Bob:
Problem with flechettes in Traveller is that they are not stable in vaccuum or thin atmosphere, so spin-stabilized APDS may be more common.

What would you be doing using a weapon with ANY recoil in vaccuum? (which is usually Zero G also)

That's what they have lasers for. Good penetration, no kick. (Well, close enough to no kick that only physics geeks would argue).

They work well in thin atmospheres too.

 

[kaladorn]

Originally posted by Corejob:
If you use a suitably high velocity projectile, like the flechette, the drop is negligable over combat ranges and so ranging is not an issue.

And there are optical ranging methods that don't rely on active sensors, they just aren't a simle to make. Image coincidence was widely used in the days before laser range finders and could be automated without major difficulties - they's just be more complex. You can also range via known object size, which works fairly well - consider the ART scope - but i'm not sure of it could be automated.

It seems simpler to just not have to deal with it. Besides, high velocity projectiles also minimize the effects of wind drift, something no sighting system will be able to do well. [/QB]

While mostly true, this just doesn't get to where I was going.

A fast projectile won't solve the weapon alignment issue. That's what I was suggesting - a way to get the user to be *sure* he's aimed at what he thinks he has, and to be *sure* the weapon is setup to fire at the optimal range (drop/dispersion/etc). Yes, you can remove drop, but you still need dispersion and a weapon with a tunable dispersion would allow perhaps the same dispersion at most ranges. And the issue of the soldier knowing he's aiming the weapon at his planned target still exists with fast projectiles.

Most of the time, you'll have nearby objects of unknown dimension. And most of the passive methods of range estimation are okay, but not fantastic. And hard (I suspect) to automate.

So I see a faster projectile being an asset in the equation, but not really addressing the core problem.

 

[kaladorn]

Originally posted by Corejob:
Anyone got ideas?

Feed from a cassete into which you load
magazines. The system strips a round and makes that particular sub-mag live after ejecting the spent mag. This creates an opening to feed in a new mag.

Well, I've never been keen on the idea od PDWs. I persobally think it is a solution to a non-existant problem. And pistols have been relatively meaningless weapon for combat operations for about a century. They're primarily badges of rank of emergency arms when anything is better than nothing.

For strict combat, yes.

However, this ignores a *lot* of police, security, and concealed carry purposes. There are so many of these applications, I think you'd be remiss to call them *special purpose*.

And in these instances, you just can't get a large flechette (regardless of propulsory tech) into the handle grip. So it means some alternate mechanism is required if a small (5mm or less) round won't do the trick.

 

[kaladorn]

Originally posted by Corejob:
You can remove the safety by putting you finger into the triggerguar and are instantly ready to shoot.

Doesn't Glock use something like that for a safety (at least a safety that is integral to the trigger)?

I've never had problems either, but then we've learned to find the safety. The above is a system that extremely obvious, even to someone who's not handled a weapon before.

Fair point, though I'm not sure 'assault weapons' 'live ammo' and 'unfamiliar with weapons' should really be combined...

I've always admired the simplicity of this system, the same way I like the fact that on the K-98, when the weapon is on safe, the safety tab blocks the shooters line of sight. Simple, elegant and effective.

That's very sharp, actually.

Technically, the sabot is going to be stripped by air resistance. This is not a problem, as it is a very mature technology.

Well, how far would it travel, given the high speed? Does this mean some alternate rule is required to handle the 'point blank' scenario before separation?

Let me see what I can come up with.

Thy boots, filleth.

 

[Badbru]

Originally posted by kaladorn:
</font><blockquote>quote:</font><hr />Originally posted by Uncle Bob:
Problem with flechettes in Traveller is that they are not stable in vaccuum or thin atmosphere, so spin-stabilized APDS may be more common.

What would you be doing using a weapon with ANY recoil in vaccuum? (which is usually Zero G also)

That's what they have lasers for. Good penetration, no kick. (Well, close enough to no kick that only physics geeks would argue).

They work well in thin atmospheres too. </font>[/QUOTE]This depends heavily on what version/melieu you are playing traveller in. GDW TNE Traveller lasers aren't worth the scrap metal and plastic they're made of, and trying to recall other versions of Traveller the TL8 Laser's aren't so crash hot either IIRC.

 

[kaladorn]

I thought the G-11 was 5 or 6 round bursts (at least early on).

Now, another point:

Install a small MP3 player in the buttstock. It load the 'I'm changing mags' noise. (We used to do this in paintball by having a 12 gram co2 in a puncture tube which you carried in a pocket, puncture it and it sounded like you were changing your co2 and the enemy would come running... only to find they were saddly mistaken).

I think autoeject might be an idea better applied in the event you had multimags. Otherwise, I agree with Straybow.

 

[Todg]

Originally posted by Straybow:
I'm having difficulty imagining what that last sentence means. The cassette is above the barrel in front of the grip, with the ammo somehow passed back to the chamber, perhaps ¼ the length of the weapon?

Something like that. Look at the HK G11. Now also look at the Colt ACR, with its raised sighing rib along the upper portion of the handguard. This rib 9or in the case of our ACR) serves the same purpose as the rib on a shotgun - it's a handin reference for point shooting.

I also don't like the cassette ejecting automatically. In WWII the M-1 clip holder would eject after the last round was fired, and the enemy learned to recognize the "ping" that meant "I'm reloading now, gimme a few seconds."

I love it when this chestnut comes up. It's simply not true. Try this experiment. Take a garand to the range and without wearing hearing protection, fire 8 rounds of 30-06 and then see idf you can hear the en bloc clip being ejected.

It's a bit of military urban legent that has no basis in fact. Maybe we should send this one off to myth busters.

In any case, it a feature you can dispose of if you don't like it.

Next question, why 5 round bursts? Did somebody point to data on the optimum burst size that I missed? I know 3 is the burst used for most military guns because of recoil and cyclic rate, but the G11 also used 3 despite low recoil and 2000rpm rate.

Fiver rounds was the number that was originally used by the burst simulators built during the SPIW program. The 5 round simulators had a higher hit rate than later 3 and 4 round burst test fixtures. Also, the recoil of 5 rounds or our flechette ammunition just happens to equal the recoil energy generated by the M-15. And 100 is nicely divisible by 5.