[Wild Goose]

Generally speaking, on the subject of barrel length for assault cannons I don't think that's such an issue for the 36mm. The Bushmaster II is 2.4 meters long. A 3 meter barrel should be fine.

Originally Posted by Heir of the Void

See, you're assuming the switch to smoothbore happened, though. Near as I can tell, it was late-60s early-70s; at that point, the BETA would be clearly established as a threat (as they were killing everyone on the moon), even if they had yet to land on Earth. Maybe this ammo commonality fixation would make sense in a purely modern context, but the BETA threat goes back too far to be ignored in weapon geologies.

And in a larger sense, with only six cannon rounds per mag, you can't be wasting shells on a single target except Fort-class and maybe Heavy Lasers. Sure, you can front-kill a destroyer, maybe even with one round. Problem is, it has friends.

Development of the Rheinmetall L44 gun began in 1964 and ended in 1974, with production beginning that year. The Soviets meanwhile were already fielding smoothbore guns since 1965. It's kind of surprising to think of how many things still in use were designed so long ago.

I'd also argue that with only six rounds per magazine, it's more important that whatever rounds you fire have the best chance to penetrate and do damage. Sabot fired out of rifled guns just isn't that as effective as sabot fired out of smoothbore guns.

I should also point out that pretty much everybody in NATO standardised around the 105mm L7 gun and the 120mm Rheinmetall L44 gun during the Cold War. Plus everyone using either 105mm or 155mm for arty... ammunition commonality isn't as new a thing as you think.

No, you're using canister so you don't have to start hitting them with a knife. Even if the chaingun is more efficient, it's not faster for reasons that really should be obvious; the gun has to move to each target, and that is only shown to be able to happen so quickly. Canister gives you spread and multi-target engagement capacity with a single system motion.

*shrug* There's nothing keeping you from loading canister in the 120mm underbarrel if you need it, though I should point out that we can infer that canister is going to be relatively short ranged, based on AARs from the Iraq war, and the fact that the tungsten ball bearings are expelled from the muzzle.

That said, you are aware that the Gun Sweeper configuration is a thing, right? And that nothing really stops you from using more than a single gun at once (save perhaps the lack of extra guns to carry, but if you only have one gun that you're already fucked in more ways than one). PLus y'know, the chaingun is a fully automatic weapon, so it's got the ROF to deal with the follow on BETA coming behind the one that just got killed.

No, no, that is not correct. A tank gun needs a long barrel to allow full practical acceleration of the round; a larger-caliber shell needs a longer barrel so as to have the same proportional gas expansion as a lower-caliber weapon will with a proportionally shorter barrel.

Yes, and because you have all that you mentioned above, that long barrel allowing you full acceleration and your max muzzle velocity, you can reach out and touch someone 2km away and penetrate him.

Therefore, either an Assault cannon round must accept reduced muzzle velocity, and thus must be built to function effectively at lower speeds (which changes the aerodynamics) but could share a propellant charge with the tank shells, or would need to have a larger charge to achieve the same muzzle velocity, and thus could share a shell with the tank, but need a different propellant charge for each shell. Most likely, they would accept some reduced velocity and some increased charge and thus be able to share neither at the same caliber, but that's fine because you generally mate the charge and shell at the factory anyway, and trying to do so on the front is a terrible idea for a multitude of reason.

Plus, the fact that the 120mm magazine is too big to reasonably use springs and that the magazine box is disposable means it would probably be best to ship the rounds in the magazine, so that kind of renders the whole thing somewhat pointless. Ammo stacking is addressed blow.

At any rate, I do agree that firing 120mm shells out of a shorter barrel won't be as effective as if you were firing them out of a real tank. Deffo there'd be less muzzle velocity. *shrug* I do think it's quite possible that you have different flavors of the same 120mm sabot rounds, just with different casing sizes for TSF and tank use, with the TSF rounds having more casing in order to pack in more propellant to try and mitigate the shorter barrel.

As for how the magazine feeds, I have no fucking clue. At least with 36mm it's all on a linked feed. Like a giant ammo can for a Bushmaster.

Depleted Uranium has a density of 19.05 grams per cubic centimeter, and tungsten has a density of 19.25 grams per cubic centimeter.

Yeah, my bad. I was thinking of adiabatic shear and got them mixed up. (I really should keep this bookmarked.) Basically comparing US DU sabot to tungsten sabot, more of the muzzle velocity and momentum is devoted to a bigger, longer round that is also self-sharpening and burns on contact with air.

First of all, why the hell are you using a stick mag? The proportional geometry is basically the same as 12.7mm rounds for an infantry weapon, but with the notable advantage that we're talking about a scale large enough that active, powered loading systems actually are practical, because you don't need excessively miniaturized electrical components. You could do something a bit like a helical magazine, though the size means that the drum mags used for feeding aircraft autocannons is a better engineering comparison, as most of the problems with helix mags are not applicable or relativity easily solved at this scale.

You don't have Fairy Loaders, but solid engineering is even better.

I dunno. THe VN and anime don't show TSFs using stick magazine either; the underbarrel uses a single-stack curved magazine. Single stack meaning that the rounds are all arranged in a single stack that's 1 x 6 rounds tall. Compare this to say a double stack magazine, which is where you have rounds arranged inside the mag, 2 x 15 rounds.

As for why is the magazine shaped the way it is? Probably so that it can fit inside the storage blocks. *shrug* A drum mag would probably be too big to fit (and those tend to have jamming issues).

That said theoretically if you wanted to do a gun that just shoots 120mm it's theoretically doable - we see that with the railgun and the feed on the 94 Second testbed.

The Heavies do, yes, but there aren't that many of them. To me sure, I just went back checked; there is not nearly enough animation of lasers firing in the VN Operation 21st to have any reason to believe the TE or Schwarzesmarken portrayal of the lasers is incorrect. Especially considering that a short-duration series of rapid pulses is exactly how you make a working laser. They intercepted the artillery because the had a lot of lasers and a lot of heavy lasers, and they reserved them through the initial bombardment.

The sweeping might work if the lasers were arbitrarily powerful, but then when a regular laser class hit, say, a TSF, it would be gone. I don't mean OHKO, and I don't mean 'blown up by exploding fuel'. To borrow a quote:



The fact that standing in the general vicinity of someone who is hit by a laser isn't an immediate danger means we can assume this is not the case. Maybe the laser shoots you next, but at least you don't have to worry about being caught in the explosion from your wingman being converted into stellar plasma.

So, Heavy Lasers can probably intercept multiple shells per shot, but they have three times longer in-between shots, so they can probably only effectively intercept a couple of times more shells than the normal lasers.

TE and Schwarzesmarken go by the "immediately hit by pulse, killed" depiction, but going by the source VN, we learn two things: 1) TSFs have just about enough antilaser coating to last for about 5 seconds against a laser's beam, and 2) a laser can burn through your coating if you don't immediately drop out of the line of fire. SO yes, this does suggest to me that Lasers, and not just Heavy Lasers, use sustained beams.

If you can't pinpoint the lasers as soon as they start firing, you really just aren't trying. In an atmosphere, there is going to be some beam scattering from the atmosphere, as well as minor heating of the atmosphere. You point a wide(ish)-angle passive system, one component looking for the scattering, one from the photons, and use the dual phenomenology to isolate results. The fact that lasers are... laser straight... and light-speed weapons means that you only have to isolate one portion of the beam to trace it back to the source.

Right, and what device are you going to use to do all of this detecting work?

Because if you have TSFs flying to where the lasers are... well those TSFs might as well kill them. It's partly why the OA-10 FAC concept didn't quite work out as planned since if you have an A-10 spotting targets it may as well just shoot those targets already.

Also, lasers in general will produce a lot of waste heat. Some are more efficient than others, but at high energies, even at the really efficient ones still produce a ton of waste heat. So spotting them with orbital IR, or surface IR observing the large plume of heated air from sustained firing, really isn't going to be that hard.

...Wait. Can the characters see the lasers, or is that just us?

I dunno. In TE Episode 1 we see the drone looking for lasers and getting shot - the laser isn't appreciably that much hotter. On the other hand military FLIR is basically either white-hot or black-hot black and white and therefore we can't really see or measure appreciable increases in heat. Thermographic camera, a FLIR ain't.

Then what the hell is sustainable? Certainly not a strategy that doesn't involve lots of artillery; the BETA can replace all their combat units far more easily than Tactical Armor can be replaced. Expending ten thousand shells and sundry to not lose one modern TSF is a solid trade, even just on the basis of cost.

Nothing is sustainable. That's the point, actually. The war with the BETA is an attritional war, and it is a war the humans are losing, because they have to spend their resources like water to draw even tactically with the BETA, and every stalemate - let alone a victory! - has a ruinous cost in material, ammunition, and lives.

So sure, for that one engagement you've shot yourself dry and your battalion's out and needs replacement. Do you have replacements? You'd have to arrange ammo resupply, rotating a fresh unit to replace your spent arty battalion and a thousand and one details... and the BETA are happily easily replacing their losses.

You're coming at this the wrong way. The AL is a force multiplier for the HE and ICM, and you use the AL coverage to reduce the laser positions, then go to full ICM once they're gone.

When I mention diminishing returns, I'm talking about AL smoke disrupting comms and sensors, since y'know there's a thick cloud of heavy metal particles in the air. At that point, with disrupted comms, it's going to be pretty hard to call in a fire mission.

Also you can't use AL smoke to reduce Laser-class, you can only use it to counter them. But yes, that is the point of Laserjagd - find Lasers, kill them, roll strategic bombers and arty.

Anyhow, let me just say that so far I am enjoying this spirited discussion.