Da Orkz 'eavy Artillery
Ork artillery pieces often go for self propelled guns to smaller and more mobile Mek Gunz. However, when the going gets tough, the Orks deploy the big'uns to pepper the ground with explosive munitions and rockets. We are talking about the really big Ork Gunz. The ones that can rival Imperial Ordnance in both scale and firepower. These are the Orks static and heavy artillery pieces.
Lobba
One of the most common artillery pieces.
A Lobba is an Ork analogue to an Imperial Light Mortar. So named due to its way of 'lobbing' its shells in high arcs, much like mortars. It is often used to pound enemy infantry squads over intervening obstacles. Most lobbas look like big mortars or rokkits, although the Lobbas used by Snakebites or other primitive tribes may take the form of a catapult or trebuchet.
They are often mounted on various Ork vehicles from Gunwagons to Battlefortresses or used as Mek Gunz. When used in this role, Lobbas are Grot's favourite artillery pieces, because they don't require for them to expose themselves to the enemy to use them.
'Eavy Lobba
Somewhere in-between a Lobba and a Big Lobba in terms of firepower and size.
The 'Eavy Lobba is one of the primary weapons for both the Kill Rig and the Hunta Rig. This turreted mounted artillery weapon is designed to lob shells in a rapid firing rate compared to its cousins. Indeed, you can just look at the belt of explosive shells this monster carries in contrast to the old 'drop and launch' mechanisms of its other kin.
Due to its turreted nature and rapid-firing capabilities, the 'Eavy Lobba trades accuracy and distance for sheer firepower.
Crunchwise, the 'Eavy Lobba is designed to smash hordes, even from behind any LOS-blocking terrain, whilst offering a nasty level of shots for an artillery piece. Think of it as the Griffon Heavy Mortar of the Ork Army.
Big Lobba
The Lobba's bigger and more immobile sister.
A Big Lobba is a more powerful version of the Lobba sometimes mounted on heavy ork vehicles such as Big Trakks or Battle Fortresses. It has a bigger blast but the same range as a standard Lobba. It is basically the Ork equivalent of the Heavy Mortar used by the Imperial Guard and the Space Marines.
Big Lobbas can sometimes be tolled and then statically placed by a looted vehicle. Usually Big Lobbas are manned by Grots and their accuracy depends on the moral and fortune of said Grots. Sometimes however, an Ork Boy can use these weapons, although it is rare.
On tabletop, the Big Lobba has the same range and indirect fire capability as a regular Lobba, but's so much more killy at Heavy 2D6 S6 and AP -1, letting it chew through blobs like nothing else, whilst being safe from return anti-tank fire by hiding behind a building.
Supa-Lobba
The largest Lobba of the Lobba family. Essentially a superheavy mortar if there is such a term.
The Supa-lobba is an even heavier version of the Lobba. It is normally mounted on Squiggoths or Battle Fortresses. It works like a normal lobba but is powerful enough to damage heavily armored tanks, splinter smaller vehicles into flaming debris and turn infantry into a fine mist of blood. Again, its blast is even bigger but the range is the same. The Supa-Lobba uses a bigger mortar to accomplish this.
Supa-Lobbas are usually enclosed than the normal Lobba, protecting the ammunition from accidentally exploding.
On tabletop, the Supa-Lobba has a 48" range, the same as its smaller siblings, but even MORE powerful. It is a Heavy 3D6 mortar with a S7, AP-2, D1 statline. Gargantuan Squiggoths comes with two of these things. Yeah, by this point, you're cracking swarms of light vehicles, not infantry.
Supa-Kannon
A giant Fuck Off Howitzer.
The Supa-kannon is an enlarged version of the standard Ork Kannon found on Ork Big Trakks, Battlewagons or Battle Fortresses. These massive artillery pieces are designed for destroying enemy positions and fortifications and are usually crewed by Gretchin gunners. It is a shorter-ranged version of the Earthshaker Cannon and often is just that cannon, looted and a little 'orkified'.
It is often the most popular choice for Ork artillery and it is used as the equivalent of the Basilisk Earthshaker Cannon.
The Supa-Kannon in 8th Edition is a gun that is dead killy. At an impressive range 60" (For Ork standards anyway) with nasty stats of being a Heavy 2d6, S8, AP-2 and Damage 3 (DAMAGE 3 !!!) - this hand-me-down Earthquake Cannon is dead killy indeed.
Soopagun
One of the biggest Ork artillery pieces and a giant FU to armored formations.
The Soopagun makes the Supa-Kannon look like a Grot Blasta. The Soopagun is enormously large and powerful artillery piece that can be mounted on Ork Gargants, Gunwagons, Gunfortresses or used as a static artillery piece.
The Soopagun is often too heavy and the recoil is too violent for any vehicle mounting it, thus the vehicle is often forced to brace itself before firing the giant gun. Tl;dr, this is basically the Schwerer Gustav of Ork artillery pieces.