[Heir of the Void]

Originally Posted by Wild Goose

As to why smoothbore guns, I will again state the reason of ammunition commonality. If you use the same ammo as the tanks, then you simplify your logistics by shipping everyone the same rounds. Note that Britain is seriously considering going to the Rheinmetall L56 120mm smoothbore gun for their next tank (if they don't just buy the Leopard 3) because nobody makes 120mm rifled ammo anymore. Same issue, really.

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.

Originally Posted by Wild Goose

Canister would be great on BETA infantry forms, but it would have issues with the larger beta strains, and in the massed BETA attacks we see you really need 36mm since it's pretty much the best jack of all trades round. Sure, canister or DPICM could kill Grapplers, but 36mm DU API kills them a lot faster. (While the official sources state that TSFs are using 36mm HVAP, my own perusal of the description of the round's construction has led me to believe it's essentially an upscaled PGU-14/B, the 30mm round used in the A-10's GAU-8 Avenger cannon and the Bushmaster II.)

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.

Originally Posted by Wild Goose

Well, with tank guns they're as long as they are so that you can throw rounds out to 2km plus and be sure they'll hit. I do freely admit that the short barrel is a problem - I can only speculate that it was considered an acceptable tradeoff in light of the fact that TSFs tend to fight closer to BETA than tanks should. *shrug* Military design is full of tradeoffs, in the end. I should also add that your math is a liiitle iffy, and that trying to pack in that many 120mm rounds into an underbarrel magazine would lead to weight distribution and balance issues for the rifle. :V Remember, it's the difference between a single stack magazine carrying 120mm rounds with casings and all - and don't forget the casing is wider than 120mm! - and the difference between 36mm caseless rounds.

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.

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.

Originally Posted by Wild Goose

and DU is significantly denser than tungsten

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

Originally Posted by Wild Goose

IMO anything more than 10 rounds is kinda pushing it for a single stack mag (plus the question of how the hell are the rounds feeding into the breach - it's not like they've got a team of fairy loaders there :V).

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.

Originally Posted by Wild Goose

I want to point out the major flaw in your assumption here: you assume that Lasers fire in pulses. That's not correct. They fire in sustained beams.

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:

If you were standing in the path of the beam, you would obviously die pretty quickly. You wouldn't really die of anything, in the traditional sense. You would just stop being biology and start being physics.

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.

Originally Posted by Wild Goose

This actually assumes you can find the lasers, though. Remember, air recon is pretty much out because the Lasers home in on electronics and silicon - the more high tech it is, the more Lasers assign targeting priority to it. (My pet theory is passive electrolocation, though the other answer of "Lasers are bullshit" is also acceptable. :V)

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.

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?

Originally Posted by Wild Goose

When I say losing proposition, what I really should have said was that it is not sustainable beyond a single engagement

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.

Originally Posted by Wild Goose

Sure, but this requires you to drop dense metal rounds on them in the first place, and you then need to alternate between AL smoke and HE, and eventually you're going to hit diminishing returns with how much AL smoke you can fire.

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.