DrxAbstract, on 20 December 2015 - 07:46 PM, said:
There are flechette shells for shotguns as well as slugs - It's still called a shotgun. When Battletech manuals even cite it as being a mech-mounted shotgun, there isn't much else to be said. Airburst or otherwise, spread increases as range increases between munitions release and target.
Khobai, on 21 December 2015 - 10:34 AM, said:
but its not a flechette shell. its more like an airbursting grenade with flechettes. it doesnt shoot flechettes out of the barrel, it shoots a canister that explodes when its near the target.
The LB-X cluster rounds are not air-burst weapons (like the old
Shrapnel shells) at all, but a canister round similar in principle to rounds like the
M1028 120mm canister round used by the M1 Abrams MBT, the
M336 &
M377 90mm canister rounds used by the M48 Sherman MBT, and the
XM590E1 90mm canister round designed for the M67 90mm Recoilless Rifle.
- "The LB-X autocannon can fire cluster munitions, which act like an anti-BattleMech shotgun in combat. When fired, the ammunition fragments into several smaller submunitions. This improves the attacker’s chances of striking a critical location but disperses total damage by spreading hits over the target area rather than concentrating the damage on one location." - Classic BattleTech Master Rules (Revised), pg. 132
- " A highly advanced weapon system, the LB-X could switch between ammunition like standard autocannon rounds or fire a shotgun style round that would split into hundreds of explosive sub-munitions. This style of submunition was particularly effective against vehicles, but also proved effective for short-range anti-aircraft flak, and for dispersing attacking infantry." - Era Report: 2750, pg. 98
- "The 120mm M1028 Canister Cartridge was developed for close-in defense of tanks against massed assaulting infantry attack and to break up infantry concentrations, between a range of 200-500 meters, by discharging large numbers of tungsten balls from the main cannon."
- "When the gun is fired, the canister body is propelled along the barrel. As it emerges from the gun muzzle, air pressure on the closing cup and the centrifugal forces acting on the body combine to cause the canister to break open along the four axial grooves. The 90 mm M336 canister round uses a brass M108B1 rimmed cartridge case with an M58 black-powder percussion primer press-fitted to the base. The propelling charge is 4.08 kg of M6 propellant."
- "When the gun is fired, the canister body is propelled along the barrel. As it emerges from the gun muzzle, air pressure on the closing cup and the centrifugal forces acting on the body combine to cause the canister to break open along the four axial grooves. The flechettes are then free to disperse across a conical angle of 14º. The maximum effective range of the flechettes is approximately 400 m, at which range the arc is about 96 m wide. The 90 mm M377 canister round uses a brass M108B1 rimmed cartridge case with an M58 black-powder percussion primer press-fitted to the base. The propelling charge is 4.08 kg of M6 propellant."
The main difference between the LB-X cluster rounds and its real-world counterparts is that the individual submunitions of the LB-X cluster round are themselves explosives rather than inert tungsten/steel balls or flechettes - it is, essentially,
a giant shotgun shell filled with grenades.
Proximity-detonated, Shrapnel-shell-style munitions are actually a property of
standard autocannons, by virtue of the "flak rounds" described (as an alternate munition available to standard ACs since 2310) on page 352 of
Tactical Operations.
"Despite having been a proven technology in ages past, flak autocannon ammunition remains uncommon today.
Intended to deal with airborne combatants such as VTOLs and fighters, this ammunition uses proximity charges to detonate in mid-air. While potent against fast-moving targets susceptible to foreign object damage (FOD), flak ammo is less effective against slower-moving targets on the ground because the charges scatter their shrapnel too far and too quickly to benefit from the target's mobility."
Additionally, there are the "flechette rounds" described on page 208 of
TechManual.
"
Developed by the FedSuns in 3055 for standard ACs, flechette munitions deliver a shotgun-like blast of metal shards rather than a stream of shells. Intended for use against infantry, flechette rounds can wipe out entire platoons of conventional troops in seconds and can even ravage battle-armored squads, but this ammo type loses effectiveness against armored targets such as vehicles and 'Mechs."
To summarize:
1.) LB-X cluster rounds = canister-round/shotshell (fragments at muzzle exit) with explosive submunitions
2.) Standard AC flechette rounds = canister-round/shotshell (fragments at muzzle exit) with non-explosive submunitions
3.) Standard AC flak rounds = proximity-detonated Shrapnel shell with non-explosive submunitions