Small diameter Sabot projectiles

[Badger Arms]

Are there any on the market? What I was thinking of was a .30 to .50 caliber 'dart' fired with a sabot out of a rifled shotgun. Why? Why not is more of a question. I have seen the sabot rounds out there but none of them seem to get any serious velocity. This question is really about finding a round that is more effective in states that allow only shotguns for hunting.

[Cameron Lamont]

Badger Arms This question is really about finding a round that is more effective in states that allow only shotguns for hunting.

More effective than what?

More effective than:

rifled 1oz. slug @ 1700+ fps generating over 3000 lb/ft of energy.

sabot 325 grain @ 1900+fps generating over 3000 lb/ft of energy.

The question really is... what the hell are you thinking of hunting??

Respecfully,
Cameron

[Andrew Wyatt]

Godforbid anyone ever post an idea about something new in the shotguns forum. :rolleyes:

Well, sauvestre makes a fin stabilized sabot slug of about fifty caliber, but the sabot is two piece and doesn't separate cleanly.

finding a proper sabot is the tough part, but i think a mor estreamlined version fo the saivestre with a 4 or six piece sabot would be the bees knees.

[Badger Arms]

I was thinking flatter trajectory. Ever watched somebody shoot way low or high because they thought the deer was at 200 yards when it really was a 250 yard shot? Shotgun slugs start out fast, but their BC is only slightly better than a golf ball. With a smaller diameter slug moving somewhat faster, you can shoot flatter and arrive on target with more energy downrange. The goal here is not to hunt cyborgs, I'm thinking of making humane kills on deer and elk.

I'm not talking depleted uranium here, I'm talking a smaller caliber slug. Here are some shots of what's available now that isn't satisfactory for what I'm thinking.

http://www.ada.ru/guns/hunting/Images/sabot_slug_5.gif
http://www.ada.ru/guns/hunting/Images/sabot_slug_1.gif
http://www.ada.ru/guns/hunting/Images/sabot_slug_3.gif

Now this is more like it. Make it a little larger in diameter and shorter. The fins on the rear can be larger in diameter and act as cutting instruments much like a broadhead arrow incapacitates.

http://home2.planetinternet.be/jderoos1/afbeeldingen/Sabot.jpg

[Preacherman]

Badger, the difficulty with a sharp, streamlined design like you illustrated is this: how is the energy of the projectile to be transferred to the target? Such a dart would make a clean, neat, small hole through the animal, and go on its way rejoicing. A typical slug - even a sabot slug - will have a blunt or hollow-point nose, and (except for the Rottweil Brenneke) will expand to at least some extent, thus transferring energy as it slows down. Even if it penetrates all the way through the animal, it will still have transferred 70% to 80% of its energy, whereas the sharp dart will be lucky to transfer 10% to 20%.

[Andrew Wyatt]

why not make it like the federal EFMJ? sharp n pointy in air, blunt and nost so pointy in flesh.

[Cameron Lamont]

Isn't that exactly what the Hollow Point Sabot pictured above does?
The 'point' behind the hollow point so to speak.


Regarding using smaller dart like projectiles...

It is interesting that Remington was also trying to figure out how to make slugs more effective :rolleyes: against deer and came up with nearly the opposite conclusion.

The Buckhammer (http://www.remington.com/ammo/shotshell/buckhammer.htm)

http://www.remington.com/images/ammo/express_buckhammer_big.jpg

Regards,
Cameron

[Sir Galahad]

Now, Andrew. Don't mistake a difference of opinion as a quasi-censorship. We're saying, yes, no, maybe, perhaps, or even heck no but everyone gets to have their say.

If the Sauvestre is that French slug that looks kind of like a WW2 aerial bomb, guess what? I emailed them and got no response about a purchasing query. I guess you have to be French.:rolleyes: Well, since no one over here has gotten them and no one here has seen fit to import them, it can't be that great of a projectile. More than likely some ex-maquis is making them in his basement.

The benefit of the shotgun is its large bore. Seems to me the best way to take advantage of that aspect is to make sure that bore is filled from side to side, diameter, circumference, PiR-Square, E=MC2 and all that jazz full to brimming with Sir Hunk-O-Lead when it comes to slugs. Big chunk o' lead has been settling hash for hundreds of years. Why change cooks when the customers are pacified with the cookin'? I guess there's something to be said for orderin' out now and again for something exotic, you know, maybe something hot and spicy. But nothing fills bellies like a good hunk o' lead I always say. Order! Pick-up!

[Andrew Wyatt]

in the locations where shotgun hunting is mandatory, a smaller caliber/flatter trajectory slug makes more sense. yes, a brenneke does a fine job out to a hundred yards or so, but there is a market for a slug that can reach out to 200. hell, if something came out like that that was accurate and still had okay terminal effectiveness, i'd buy some.

[WheelMan]

.... If somebody did develop a round that duplicated, in scaled down format tank round sabot performance wouldn't it effectivly defeat the purpose of shotgun only areas, particularly, limiting the long range lethality of the projectiles? I imagine if such a round became available and there were some lawmakers in your state that understood weapon performance (not terribly likely I guess. Just make sure the hulls aren't black with pistol grips and we'll okay :( ) they would soon be illegal for hunting as they pose the same dangers as traditional rifle rounds.

[Badger Arms]

I mentioned it earlier, but what about the effectiveness of fins on such a projectile. I know that broadhead arrows derive their lethality from the cutting edges on their blades. They are effective far out of proportion ot the product of their energy and velocity.

Maybe we can take the 'dart' in a different direction. I've seen folding blades on broadheads and folding fins on military anti-tank rockets. What about folding fins on a saboted projectile for the purpose of terminal effects on game animals? Further, wouldn't a 'broadhead' slug be more effective than a standard slug with all other things being equal.

[Dr.Rob]

OK, lets say, for argument's sake a .50cal 500gr bronze point spitzer boat tail could be loaded and stabilized for a 200 yard shot, say @ 1900 fps.

At 200 yards, to make a clean and accurate shot on athe kill zone on a deer, a 9 inch circle... that's what scopes are for. Now why would I want to put a scope on a shotgun when I aleady have a rifle that can do that distance, with considerable less drop and recoil? I'd gather that a "long range" shotgun slug would likely be banned in "shotgun only" areas the same way sabots are illegal or blackpowder hunting.

As far as stabilizing fins, rifling provides all the stability you need for 1000 yard rifle shots. Finned projectiles create spin by having slightly angled fins, that reduces cavitation created by the stress of acceleration. QED You don't need fins UNLESS you have a sabot. Now at shotgun velocities, the rate of twist is pretty slow. By the time your slug hits its target say it fifty yards, its not spinning like a buzz saw, rather drowsily spinning on its own axis once every foot and a half or so. (FIGURES NOT EXACT... just to illustrate) That means at 50 yards, your rifled slug has spun 100 times, and can expect to hold a one and a half inch group.

Now to recreate that accuracy you must now create a projectile, that must stay exactly true to the axis of the bore (which the traditional slug does by being hollow based) while inside a sabot, inside a plastic cartridge.
Now the fins MUST me machined accurately enough to guarantee that spin effect of say 100 times at 50 yards. Well, if you've ever machined lead, you realize that the act of firing the shell will affect the shape of the slug, that's why saboted bullets are made of copper or harder alloys. Now copper isn't that strong and can be bent with your fingers, bronze is pretty brittle and harder stuff makes a bullet that will penetrate some armor btw, and may not be legal where you hunt.

Overall, I think the issue is one of reinventing a wheel, and a wheel that is of limited utility, high cost and hard to manufacture.

As far as being lethal. Rifles and shotguns kill by generating Shock, and penetrating vital organs. Broadhead arrows penetrate deeply but do not create enough energy to create secondary missles from broken bone, bullet fragments or "hydrostatic shock" that bullets do. The purpose of the broad head is to INCREASE the cutting surface exponentially and create a wound that won't close up, and allow an animal to bleed out or be tracked more easily. You'd be suprised how many hunting arrows shoot right through a deer or elk. BTW arrows spin to stay stable, that's what the fletching is for. The effect of a spring loaded wings or blades on a projectile fired from something as primitive as a hotgun.. I doubt you'd get consistant accuracy, again based on the need of the projectile to stay bullet shaped until it hit something, yet be tough enough to not spring open upon firing.

That's my 2 cents.

[Zorro]

Why not a solid "Football" shaped slug that upsets and turns sideways on impact?

Football shape, and solid not hollow construction, would give it a little better sectional density.

[Badger Arms]

Dr.Rob:

I think you've missed the point. Rereading my posts, I'm sure I meant for the 'fins' to be cutting devices only. As for the rate of spin, that is what the rifled barrel is for. Steel seems like the obvious choice to make the projectile out of. The tissue damage is to be casued by the fins with the body of the dart intended to pull the fins through. I'm not sure how thick the fins would have to be to withstand velocities in the range of 2000 fps. Again, I'm don't think the fins will aid in stabilization, they are to cause tissue damage.

Let's not get caught up on the legality of something and automatically conclude these would be banned. Shotgun regulations are, indeed, intended to limit range but not necessarilly to limit lethality. A more lethal projectile is a plus providing cleaner kills and less wounded animals.

Football shaped slugs?

Not entirely sure this is the most aerodynamic of projectiles but it might be able to tumble in tissue well.

[Cthulhu]

Spins and Fins don't mix. Ever see a rifled cannon for the APFSDS tank rounds that are the model for this idea? The few that do use these rounds use a bearing or slip ring to isolate the projectile from the spin of the rifling. The fin airfoils keep the projectile flying point first. Spin them at the RPM of typical sabot slugs fired from rifled barrels and and the projectile will never get to the target. I'm not sure how willing current slug users are to trade range/trajectory for reduced terminal effect at that extended range. Given sufficient velocity to achive the longer pointblank rage, you would have a light weight high-velocity projectile that would slip through the target doing minimal tissue damage. Hopefully the dart breaks in half upon deceleration and tears its way out, giving you a blood trail to track.

[cpileri]

Would these help?
Collet Cup Sabot - Sabot only - 12ga, .450" diameter,
300 grain
$15.99 per pack of 25,
$14.00 at 4 packs, $13.15 at 20pks
Collet Cup Sabot - Sabot only - 12ga, .500" diameter,
300 grain
$15.99 per pack of 25,
$14.00 at 4 packs, $13.15 at 20pks
http://www.ballisticproducts.com/a1BPHome/t2-prodcatagories/Prod_components/t3components/Prod_Shot/t4-slug/Slugs/slugs.htm

These are the only 12ga (20's on the same page as well) sabot I can find that will hug a .45 cal projectile. Although it is ostensibly for a 300gr slug, I dont see why you couldn't put something of different weight in there.

Also don't know how much the sabot itself weighs.

I have never tried any of this, but maybe you could use some of barne's spitzer (solids? xlc?) types in .45 or 50 cal and load data for some heavy loads like 1.5 to 2 ounces and get that velocity and trajectory you are after.

Or, maybe someone would custom make some 12ga-.30 caliber sabot for you?

I have been thinking about this one as well.

p.s. in the other directions: how about oe of those 750gr 50 BMG or Barnes Solids 750gr (or 800gr) .510 cal (would need 2 ounce load data I'm sure); or barne's 500 NITRO (.509) 570gr XLC or 50/110 Win (.510) 300gr Original ??? so many ideas...

C-

[Dave McCracken]

A coupla things....

First, I too believe that more effective slugs are a good idea, but IMO the sabot concept has little more to offer than what's on the market today. While new models keep appearing, there's little they do the older ones do not.

And the old ones work marvelously well when inserted correctly and used within their range limits.

And if they DO make a slug with good 200 yard capability, chances are they will not be allowed in shotgun only areas. Overshooting is overshooting, whether the projectile is sped by a shotgun or a 264 Weatherby.

And, after seeing maybe 30 deer taken with sabots,I note they are often wonderous accurate. Blood trails,though, are longer and skimpier than those of bore sized slugs. This can be overcome with better projectiles, and some of the newest are attempts to do just that. Time will tell if they do.

I do see LE possibilities for a high velocity, penetrating sabot load (Say solid steel core) for shooting through engine blocks,etc, but not much sporting usage.

And you folks do not know just how lucky you are in this respect. Back in the day, most sporting goods stores carried maybe three different 12 gauge slugs at most. Now we've dozens of choices.

[Badger Arms]

Just an observation that this thread is being taken in different directions. I think that most would agree an improved shotgun slug is needed but only in the area of range and trajectory. Lethality seems to be a non-issue and I'd agree. The three major types of slugs available now are more than effective in the lethality range.

Dave: You bring up an interesting point. From a smooth-bore shotgun, you can fire a sabot projectile pretty fast. You can do this in much the same manner as the 120mm Tank Gun does. I'm wondering if anybody has done this and what the results are. Armor piercing darts fired at, what, 4,000 fps or maybe faster? Would have a heck of a terminal effect on armor, engine blocks, brick and concrete strutctures, etc. Imagine the effect on Russian designed tanks. How flat would this thing shoot! Now I'm excited.

I suddenly realized that the Moderators might smite me for taking this post in a NON-SHOTGUN direction... uh...

And, er, yes we can put some #12 shot behind the dart for secondary effects.

Whew. Hope that works.


edited for spelling

[NavyDoc]

Its not off topic. Here figure this:

get a 1/2" round steel rod, cut to length desired. (weight is lenght in cm times pi times radius squared times 7.84 grams/cubic cm times 440grams/ounce divided by 28.35)
but it will weigh about 3/4 the weight of a lead plug of same length.

Sharpen to a fine point, making it even lighter in the process.

put into one of the above 50 cal sabot.

should be really, really fast.

Sabot will protect the bore.
C-

[Nippy]

I think you're doing a good thing by trying something new. As for fins on a slug I don't know what the exact performance would be like but I have a few ideas.

If you add fins and you have a crosswind the dart will probably veer off farther than a slug would because of the fins. The fins help stabilize the darts trajectory but usually the darts oscillate around before coming into a stable mode (missiles do that). But if they are interrupted during flight (i.e. cross wind) they bounce and then oscillate for a bit until the settle down again. Oh yes fins make the dart “roll” as well and if the fins aren’t made correctly one set can produce more drag than the other thus effecting the splash pattern.

I think the main problem with a dart is that the fins make it susceptible to the medium in which it travels in. Oscillation takes away from the kinetic energy of the dart so if it oscillates more on one shot you could lose more K.E. and end up short of the target. Also manufacturing these things so that it produces equal drag/lift what not on each set would be a interesting challenge. You’re loads would have to be pretty darn consistent since you “designed” the fins for a certain “axial force” or the boom that made it go woosh.
All in all I think adding fins may insert an uncertainty into the splash pattern (i.e. accuracy) of your slug-dart.

Not saying that the dart-slug was a bad idea but I think there could be more too it than designing a regular slug. Heck, just design a slug with a better ballistic coefficient?? better shape, better aerodynamics.

[WheelMan]

I imagine a variation of the "grid fins (http://www.deskeng.com/articles/02/may/cover/main_dig.htm) " idea would be perfect for this application. They could be made of polymer for ease of manufacture and to improve consistency, perhaps affixed the round by being set against a shoulder milled or cast into the projecticle. They also have minimal area along the transverse axis to minimize wind effect. Sorry that page isn't directely about grid fins, but it has pictures.

[Dave McCracken]

Hmm, what's that Winchester superslug, 1900 FPS? Let's bypass steel and go to a steel jacketed tungsten or depleted Uranium projectile. Or use a case hardened steel splinter like the old black tip 30-06 AP, only say .50 caliber as was mentioned OR .375 for better sectional density. Pressures will have to be kept low but IMO 2700 FPS to match the 375 H&H should be realistic.

No legitimate sporting purpose, but outstanding for penetrating light armor, fortifications or those pesky engine blocks. And usable in a decent 12 gauge repeater...

[Nippy]

Badger Arms

We're talking about extending the range of a slug right? For that 200 yrd shot? Just checking to make sure because thats what I read on your original post.

[Badger Arms]

Nip: Initially, yes, but by an extension of the concept, other applicaitons have come to light. I think it's healthy to explore the concept no matter what the applications. Currently, I think we are discussing the best ways to stabilize said projectile which is between .30 and .50 caliber and considerably longer and more slender than current projectiles.

I feel that a 'dart' on the order of 1.75" to 2.25" in length would fit the bill well in a shotshell. The problems currently identified with that projectile are stability, accuracy, and lethality. These problems are considerably less important if we are talking minute-of-tank or minute-of-bunker accuracy rather than kill zones on deer. Also, a dart that is less than .50 caliber is kosher for anti-personnel applications by Military and Law Enforcement agencies. Currently, US Military agencies see the shotgun as primarilly a door breeching tool and little more. The same tool can also give an infantryman a means to take on a Main Battle tank in theory.

I disagree with Depleated Uranium as there is too great a political battle to be fought on that subject. Perhaps Tungsten Carbide with a cast aluminum fin assembly. I don't think Plastic can take the pounding that a 3,000 or 4,000 fps projectile can dish out.

[max popenker]

Badger, you too optimistic about taking MBT with the shotgun-fired sabot. They don't make the tank smoothbores of about 5" for nothing.

the 15mm Austrian Steyr IWS-2000 Anti-materiel rifle fires 308gr tungsten flechette at 4750 fps. Yet it is capable to dealing with only 40mm (less than 2") of RHA at 1000 meters. Current MBTs have armour of much more than 1' (usually in equivalent of 500+mm), so even an point blank this gun will fail at MBT, unless fired straight from the top at the engine compartment cover.

yet, this gun 5-6 times heavier than any typical shotgun (~39 lbs) and have complicated recoil-dampening systems. Ammo is also much, much larger than any shotgun shell (see it compared to .308win below)

http://world.guns.ru/sniper/steyr_amm.jpg

some detals are here: Steyr IWS-2000 (http://world.guns.ru/sniper/sn46-e.htm)

the hunting arrow-shaped saboted shotgun slugs were developed in Russia in late 1960s (i talked with one of the designers lately by phone), but were never put into production. i can find some details if you interested.

[Badger Arms]

Max:

I'm assuming you meant 50mm, not 500mm there, we aren't talking battleships here. Even so, you don't have to penetrate frontal through-and-through to kill a tank. You only have to put a round through enough plates of reactive armor, take out the periscopes, blow the tread off, pop the extra feel tanks, put a hole in the Main Gun Barrel, dismout a wheel, or wedge a round between the turret and tank body. When infantry is a good distance away, they can hide and let the tank pass or engage it with air support, tank support, TOW, or many other weapons. This is a close-in concept I'm considering.

Secondly, you don't intend to use this as a primary weapon. The primary weapons are the MUCH lighter rocket/tube concepts that are much more effective but also much more expensive.

Funny aside here. One thing I remember seeing in the footage of Operation Stomp Saddam was a Marine light infantry unit trying to destroy an abandoned tank. They launched a TOW missile at it from a distance of about 50 yards. The TOW didn't get a chance to stabilize and it flew right over the top of the tank. It was a sad waste of money. I'd imagine a good 'thermite' grenade down the barrel would have done the trick much better. Such large weapons illustrate the lack of an effective close-in weapon to engage tanks that is still light enough that you don't have to have a squad to operate one.

[Dr.Rob]

I wasn't trying to shoot the idea down I just don't see a way to make it economical, and yet still getting the desired effect.

I still think fins will cause more deflection at shotgun velocity than good.. unless it was possible to make them flex.. and then they wouldn't do any wounding.

[Cthulhu]

We moved from extending slug effective range to 200 yds to disabling MBTs.

I'm all for exploring new ballistic concepts, but talk of disabling tanks using shotguns is nonsense. To say in theory it is possible would be accurate, but in theory we can live forever and travel faster than light. Given the low pressures shotgun shells operate at, getting any projectile to travel at 4000fps would be a feat. Just because Winchester can hurl a slug at 2000fps (out of a 30" bbl, I might add), doesn't mean that 4000fps is just a matter of adding more or better propellant. The law of diminishing returns takes effect quite rapidly as powder capacity and pressures grow. It has been estimated that to double the velocity of a .220 Swift (45grn at 4100fps) you would need to burn 8 times the amount of powder. Even then I don't think it would work. To add velocity by upping the operating pressure, (also a natural consequence of burning more powder) you must beef up the shells and and the gun.

Say for the sake of argument that you manage to find a way to propel the proposed 2.25" steel dart from a conventional shotgun at 4000fps. That would approximate the KE of the Steyr AMR described above, and give less penetration due to higher crossectional area, lower density and lower velocity. These KE Sabot projectiles reley on high velocity and high sectional density. One or the other doesn't cut it. Using them close in wouldn't necessarily be better, as the dart would be more likely to shatter upon striking the armor plate. 500+MM thickness is accurate for the front armor, and the armor on Brit, American, and former soviet tanks is a composite armored matrix specifically designed to defeat the penetrative effects of SAP projectiles as well as HE/HESH/HEAP rounds. This is in addition to any reactive armor added to the outside to disrupt HE/KE projectiles.

Basically, the scenario would be, fire this at the tank, scratch the paint, and be ventilated by the coax/commanders cupola machine gun, or be vaporized by the main gun. What if you manage to trap the tank in close quarters it and employ the uber shotgun close in? You would more than likely be killed by detonating reactive armor, or by fragments of the wholy inadequate projectile shattering on the surface of the tank. If you are close enough for an accurate shot with such a weapon, you are close enough to employ a conventional HE explosive projectile, which pack far more energy in a compact space, are not dependent on velocity, and produced en mass, are very cost effective.

These problems are in addition to little issues like barrel life, lack of pin point accuracy( for those sighting block shots), high velocity shedding/reduced effective range due to lack of SD, and stunningly high levels of recoil.

By contrast, spin stabalized lead footballs that tumble upon striking are far more feasible as effective shotgun rounds.

[Badger Arms]

I'm all for exploring new ballistic concepts, but talk of disabling tanks using shotguns is nonsense.

Your points are valid for convenional projectiles, but we are talking saboted darts. 4000 fps is easilly achievable. You don't increase the charge weight that much, you DECREASE the projectile weight. Do you realize that 500mm is about 20in? I'm not a crunchie, so correct me if I'm wrong but that seems a little thick. But again, I'm not going for a frontal shot here. Given what you have said, the A-10's 30mm shells should bounce off of tanks, but they don't... they penetrate very well, thank you. I think this is really a question of paradigm shift here. For this theory to work, we have to ignore the fact that frontal armor is very thick and our 5.56mm bullets can't penetrate and start looking for ways to increase the velocity and penetration of a round without massive logisitical outlays. I think that 4,000 fps is doable with a small dart out of a sound shotgun. I think that a tungsten carbide or DU constructed dart would penetrate very well, thank you.

[Cthulhu]

Unfortunately I was talking about saboted darts. Does anyone think a shotgun shell, using sabots, operating at pressures shotguns and their hulls can tolerate 12K-16K, can accelerate a sub caliber dart to 4000fps, when a .220 Swift or .22-250 operates at 60+ psi just to toss a measly 45grain bullet at that speed? APFSDS cannon projectiles weigh upwards of 10 pounds, burn pounds of propellant, operate at very high pressure, and rely upon interior spalling of the tanks armor as well as thermic reaction of the DU projectile igniting as it passes through the hull to cause casualties to the crew and secondary explosions from stored munitions. They don't just rely upon velocity alone. As I said before. both velocity and projectile weight matter. You can't just keep dropping the weight until you get the desired velocity. KE= 1/2MV^2, so cutting the mass in half also drops your KE by the same amount. You end up with a hyper velocity flechette the size of a roofing nail that would have a hard time causing a casualty on an infantryman, much less a tank or armored vehicle. Flechettes are nothing new, and their capability has time and again been found lacking.

Since its some what relevant for showing why some rounds work and others don't, I'll address the A10 round example. For 30mm GAU-8 rounds, you are talking about a 30mm API projectile with a sub caliber DU core that alone weighs 0.66 pounds. Penetration at 1000M is about 40mm RHA, given an initial velocity of 1070ms. In the field you must also add the planes velocity to the speed of the projectile, increasing its effective MV and ultimately its lethality. It is attacking at a downward angle (to better reach the thinner top armor and fuel/ammo stores) and the cannon is launching between 40 and 70 of these rounds, mixed with HEI projectiles, per second at the target. Combat analysts found that 6 rounds were required to "kill" the average tank in the Gulf War.

Also, the 500mm RHA figure is an equivalent measure, used as a baseline for armor penetration. Few tanks use actual all steel armor plate anymore, as most use ceramic metal matrix armor to achieve an equal or greater effective thickness without the weight of steel. While the actual armor might not be 20" thick, it is effectively equivalent to that much rolled homogenous armor. Most tanks also have sloped armor, which requires the projectile to pass through at an angle and thus increases the effective thickness of the armor.

My point is that a shotgun based platform cost advantage over conventional man-portable HE anti-tank weapons is negligible if it cannot penetrate armor without complete and totally transforming modifications and or re-engineering. AT-4s and the like work, are already in place, and are cost effective from a military prospective.

[Glamdring]

Badger Arms: Are you sure it wasn't a newer TOW? IIRC the newer ones are designed to fly over top and attack thinner top armor.

[Badger Arms]

Don't know for sure. I just watched it on TV. It almost looked like it skipped off the top of the tank. The warhead didn't go off though. I suspect that, like the 40mm projectile grenades, these things have a minimum range required to arm their warheads.

[JShirley]

Guess I need to study the ITAS manuals I got from the 19K's in my company!

I like the 12 GA shotgun a lot. I have thought about a variety of loads for it in the last few years, including Triplex and low recoil rounds. I think a saboted 200 grain Gold Dot or EFMJ sailing out of the tube at about 1600 fps would be the bee's knees, and would still have considerably less recoil than standard slugs. Should work fine for close-in deer, pests, or well, pests.

I have also considered a saboted load of something like that black tip .30 bullet, saboted and loaded to perhaps 2200 fps. I have absolutely no delusions that it will penetrate or do anything else than perhaps annoy a MBT.

Guy, that would be the TOW IIB.

[Badger Arms]

I think that There might be some misundertanding here about Sabot or Flechette projectiles and how they get their velocity. Consider the Steyr Advanced Combat Rifle entry (does anybody remember... the one with the sideways rimfire shells?) that had a shell which was about 20% the SIZE of a shotgun shell yet it was able to produce some impressive velocites. The ACR Ammo produced a velocity of nearly 5,000 fps with a 10gr projectile despite being so small. Other posters keep throwing out numbers around 2,000 fps and this is simply not what you'd get from a flechette round, even fired from a shotgun only designed to handle 3.5" Magnum buckshot loads.

The reason we get such terrific velocities from such low pressure is the nature of chamber pressure. Pressure is exerted equally along the entire surface area being acted upon. For any gun which fires a projectile from a non-tapered bore, this area is the diameter of the bore. When we increase that surface area and decrease the weight of the projectile (Flechette plus Sabot in this case) we get a substantial increase in velocity that is difficult to understand from a lead-based logic foundation.

My question is why a shotgun that can launch 438gr projectiles at 1760fps cannot launch an 80gr, .15 caliber dart at 4,000fps. Am I missing something here? Did the physics of pressure and velocity suddenly change and I didn't get the memo? Am I nuts to think that said dart would be incapable of setting off reactive armor or shattering the gunsight on a tank? Can it not penetrate the auxiliary drum tanks that many Russian Tanks use? Can it not create one hell of a hydrostatic shock on a soft target? Can the 'fins' that stick out from it not make some pretty nasty incisions [on the deer]? Furthermore, will it not shoot flatter, have a BC much closer to one, and carry more energy downrange?

I don't have a manufacturing or R&D Capability so this is all academic anyhow. I'm just wondering why I seem to be so far off in the theory here and I doubt that I am.

One does not have to obliterate a tank to remove it from action. Small-arms fire does not set-off reactive armor yet flechette rounds certainly would. What do you think of said projectile's effectiveness on concrete, light armor, or other structures such as vehicle engine compartments?

http://online.comcast.net/help/
http://www.casusbelli.iespana.es/casusbelli_es/arsenal/steyr_acr_mun_02.jpg

[JShirley]

Even if one could throw that .15 penetrator at 4000 fps, I postulate that the damage inflicted would be minimal. If this was such a great idea, why is there not a penetrator round for the M203 40mm? It's a single-shot launcher, so it could even have a round that extends further than other 203 rounds.

John

[Cthulhu]

When we increase that surface area and decrease the weight of the projectile (Flechette plus Sabot in this case) we get a substantial increase in velocity that is difficult to understand from a lead-based logic foundation.

The misunderstanding here is that the above statement is not true. The pressure vs velocity vs surface area relationship is the same regardless of the construction of the bullet/sabot/dart/what have you. There is no special lead-based physics that suddenly do not apply when we hurl plastic sabots. The sabots total area is the same regardless if it houses a 1oz .50 cal wasp waist slug, a .70 cal lead 1oz slug or the aforementioned subcaliber dart so we are not increasing surface area. The only thing here affecting the outcome is the weight of the projectile. If all other factors are equal, it is true that as weight goes down, the velocity will increase. But it is not a linear relationship, not in rifles, pistols or shotguns. Dividing the weight by two may only increase velocity by 20%, and halving it again will affect it even less, up to a point where the return is negligible vs the reduction in KE due to reduced mass.
Once you've reduced it to 80 grains, the only option is to add pressure, either by adding more powder, adding barrel length, or using more powerful powders. Again we run into a non-linear powder capacity vs velocity relationship, where the amount of powder burned skyrockets to achieve a relatively small increase in velocity.
This is in addition to other problems to this end of the solution.
That large sabot housing the flechette really eats into powder capacity, even with a 3.5" shell. The light weight sabot more than likely does not provide enough resistence to let all that powder burn efficiently, further reducing velocity gain from the additional powder.
Prior to this there was never a proposed dart diameter or weight.
You might be able to achieve enough pressure to obtain the spec velocity from the 12ga bore, but the pressures would require a completely redesigned hull and weapon.



My question is why a shotgun that can launch 438gr projectiles at 1760fps cannot launch an 80gr, .15 caliber dart at 4,000fps. Am I missing something here? Did the physics of pressure and velocity suddenly change and I didn't get the memo?

Can it? Yes. It is possible. At pressures any shotgun shell or shotgun can safely tolerate? Not likely. The little ACR could do it, yes, by throwing a dart 8 times lighter, using chamber pressures 6 times higher.

Am I nuts to think that said dart would be incapable of setting off reactive armor or shattering the gunsight on a tank?
A .223 or .308 can shatter the gunsight glass, obscuring vision. .308 AP can penetrate 120mm of plexiglass alone.
Reactive armor is designed to defend against chemical HE weapons, not KE weapons. The explosive used inside is as insensitive as possible to avoid premature detonation, and the plates are desinged not to react to small arms fire or shell fragments from grenades, bombs, artillery etc, all of which are capable of producing projectiles with the weight and velocity of the proposed dart. Even the APFSDS rounds are unlikely to set off most types of reactive armor, they just punch a hole in it.


Can it not penetrate the auxiliary drum tanks that many Russian Tanks use?
Yep. So can .223/.308 AP.

Can it not create one hell of a hydrostatic shock on a soft target?
Maybe, but flechette ammunition has time and time again been found wanting in the terminal ballistics dept when it comes to soft targets, whether the researchers subscribe to the theory of hydrostatic shock or not.

Can the 'fins' that stick out from it not make some pretty nasty incisions [on the deer]? Possibly? How big of fins are we talking about ? If its a 0.15" diameter dart, just how much larger are the fins than the body of the dart? Say 3 times the diameter of the main shaft? Those are going to be pretty small fins. They are not as large as say the cutting blades of a broadhead arrow. If they don't shear off from striking the target at high velocity, they would probably add minimally to the cutting damage. Tissue damage from fins was never mentioned in any research of Flechette wounding mechanisms. Most of the data suggests that wounding was similar to conventional small bore ball rounds when the flechette tumbled and broke up. When it did not, wounding was far less significant. This was with lighter, higher velocity and weaker constructed flechettes, that are more likely to shear and tumble.

Furthermore, will it not shoot flatter, have a BC much closer to one, and carry more energy downrange? Yes, Yes, Yes. But how will it transfer this energy to the target when it reaches it?

Switching gears again from deer to tanks, the most daunting problem for this new uber-round is not pressures, velocity mechanics, increased weapon bulk, accuracy, etc, but the fact that the round will not damage armor significantly better than what is already afield. Say we could somehow get the proposed ballistics from the round. Lets compare it to the already sub-par experimental Steyr AMR round.
Steyr AMR: .223, 308gn, 4750fps, SD 0.885, KE 15,473ft/lbs, PF 1463
Penetration: <40mm at 1000m
Uber-Slug: .150, 80gn, 4000fps, SD 0.508, KE 2843 ft/lbs, PF 320
Penetration: <<< Steyr AMR

The proposed projectile falls weigh behind in the categories that affect armor piercing, namely mass, sectional density, velocity. Its lower diameter is offset by its much lighter weight, so that wouldn't give it any increased performance. I included KE for those people who believe KE is the only factor by which bullet performance can be measure. IPSC PF is included for fun and those who love momentum. Anyway you measure it, the uber-slugs performance on armor will be vastly less than the already inadequate Steyr AMR. Also consider .50 Cal SLAP ammo can penetrate >75mm RHA out at 1500M, with no changes to the weapon other than the ammunition.

Take a jaunt into fantasy again, and say that the requisite velocity could be produced from a conventional shotgun. Now you've given the infantyman another weapon that is less accurate than a sniper rifle, causes inconsistent wound that are likely to be less severe than his battle rifle, and requires bulky ammunition that allows him to carry less rounds per load out. Be sure to let him know that it isn't selectfire, doesn't penetrate heavy armor or deliver an explosive payload. I'm sure grunts will be lining up to carry that weapon.

[JShirley]

Thanks. I was really too lazy to say all that, but I'm glad you did.

Just bought my first Lovecraft this past month...

John

Incidentally, it is now believed that large-caliber mortars may be more effective than previously thought on enemy armor(ed vehicles). Unfortunately, the 120mm was not tested in the article I read.

[Badger Arms]

40mm subcaliber projectiles: I don't think the barrel is long enough on the M203 to give enough velocity to make any difference.

I'll concede that you can't take an M870 and turn it into a APFSDS (Armor Piercing, Fin stabilized, Deer Slayer!) or tank slayer for that matter. Wonder if a purpose-designed 'large bore' flechette rifle would be able to have a significant gain without the weight penalty of the Steyr weapon. Applications? Heck, this is all theory anyways so I can't think of one right now but I want to spit darts out at 5,000fps for the heck of it.