Bench 4: five cheap and mid-cost Tyranids (2026-10-02)

T-564's workbench on Zoanthropes, Von Ryan's Leapers, Neurogaunts, Pyrovores and Tyranid Warriors with Ranged Bio-Weapons. Baseline: all ten switches on except bestSize. What-ifs ran in a scratch copy of tools/tierbench.js over the tracked raw table (reports/tiers/2026-10-02-tyranids-raw.json, which reproduces round 10). Another process rewrote build/tier-raw-tyranids.json at 19:16 UTC during this run (baseline ρ 0.771 there, counts unchanged), so the tracked copy was frozen. Rules come from Wahapedia's 11th-edition pages, in our own words. Lists: grimstat-corpus (CC BY 4.0), 23 Tyranid lists. A report: nothing here changes a published score.

In short

• Baseline: within one 34 of 44 on our within-army ruler, and 38 of 44 (86%) on Auspex's shape (our order cut 13 S, 7 A, 13 B, 4 C, 7 D). So the 85% line is met once the letters follow Auspex's counts. Same letter: 22 and 26. ρ 0.76.
• The ruler is most of the gap. Our quota gives 5 S and 8 A of 52; Auspex gives 13 S of 44. The Leapers (15th) and Neurogaunts (9th) are S on Auspex's shape.
• bestSize: its whole gain is absolute survival. With incoming fire scaled to points, no unit gains from a larger size (within one 34). It helps the three units the lists field large and inflates the hordes the lists field small. Per unit, "the better of the smallest and the most-listed size" (minOrListed) gives 35 within one, 42 on the shape and ρ 0.78.
• Verdicts: Zoanthropes and Ranged Warriors: size (minOrListed). Leapers: Stealth unmodelled (B → A). Pyrovores: Feed the Swarm's flat cap (C → B). Neurogaunts: no change of their own.
• Bugs: docs/bsdata.js makes a conditional Stealth unconditional on four Tyranid units (section 4).

1. Yardsticks

Shape: our 44 graded units ranked by the tie key and lettered with Auspex's own counts. This is a yardstick, not a proposed ruler (decisions.md: nothing is fitted on Auspex).

With the package, nine units are still two letters off on our ruler: Exocrine, Hive Tyrant, Maleceptor, both Norns, Pyrovores, Tyrannofex, Winged Hive Tyrant and Zoanthropes. On Auspex's shape only three are: Neurogaunts, Carnifexes and Hive Tyrant.

2. bestSize: who it helps and hurts

Gap = Auspex minus ours in letters.

Helps: the three graded units the lists field large: Hive Guard, the Melee Warriors and Zoanthropes. Hurts: the units fielded small but scored large (Neurogaunts, the Ranged Warriors, and Gargoyles, Termagants and Barbgaunts, which are ungraded), and every single-model unit they pass. Why: per point, a bigger squad deals and soaks the same. Only turns alive grow, because the typical fire doesn't grow with the target. With fire scaled to points, best size falls back to the smallest (34; Hive Guard picks 3 again). So "best size" by our measure always means the biggest. Use the most-listed size, per unit, never below the minimum (minOrListed). Most-listed size alone sends Pyrovores to 2 models (−12, C → D), because their Banner per point favours one model. Caveat: Hive Guard's 6 rests on one list.

3. The five units

Zoanthropes (90 pts / 3, 190 / 6; Auspex S, 16 lists)

Check. T5, 5+, 4+ invulnerable, W3, Fly, Synapse; two Psychic Warp Blast modes, scored as alternative profiles. Warp Field (a 6+ invulnerable aura) is in the baseline through auraToNeighbours. Spirit Leech is noted: it needs the enemy's Battle-shock as a dice result and is worth a few wounds a game. Psychic attacks ignore hit modifiers and cover: worth nothing on our no-cover table (+6.5 in residuals-1's terrain run).

Verdict: size, then the ruler. At 6 models they are 23rd of 52 (Hammer 88). The quota's 5 S places hold them at B; on Auspex's shape they are A. The rest of the S is the Synapse brick, whose Battle-shock help we don't credit. Change: minOrListed: it also moves Hive Guard +20.6 (D → B), Broodlord and Genestealers +15.2, Melee Warriors +14.7 (C → B) and the Neurotyrant +2.0.

Von Ryan's Leapers (55 pts / 3; Auspex S, 12 lists)

Check. M10", T5, 4+, 6+ invulnerable, W3; 6 attacks each at WS 3+, S5, AP −1. Infiltrators is modelled (reach 95; the walk way starts 12" away). Stealth and Fights First are not modelled: tiertest.js reads neither. Pouncing Leap (a cheaper Heroic Intervention outside the once-a-phase limit) is noted, CP only. Synapse: the Leadership part is 0 for every Tyranid.

Survival is the whole gap; the Lictors' Lone Operative doubles theirs. The Leapers' damage, the best of the five per point (141 per 100 pts into GEQ), isn't in Runner.

Verdict: a missing quantity. Stealth is on the datasheet and gives the benefit of cover, a rule we already apply. Change: Stealth in survival (Anvil and Runner). It moves Gargoyles +3.4 (A → S), both Raveners +2.3, the Neurolictor +1.6 (A → S) and the Deathleaper +1.4. Biovores, Hormagaunts and both Norns drop across the S and A lines, so within one stays at 34.

Neurogaunts (45 pts / 11; Auspex B, 2 lists)

Check. T3, 6+, W1, OC 1. Neurocytes (Synapse near a Synapse unit) is noted; residuals-3 measured the relay at almost nothing. Data: build/units.json has the larger size as 21 models; the datasheet has 22.

Anvil raw 20% below Hormagaunts' is 1 percentile point lower: every horde sits in the pool's top 4%.

Verdict: no change of its own. minOrListed removes the two letters. N1 lowers every horde together and costs 2 within one. The +1 that remains is popularity between near-equal hordes, and the lists agree with Auspex.

Pyrovores (40 / 70 / 100 pts for 1 / 2 / 3; Auspex A, 4 lists)

Check. T6, 3+, W5; a 12" Torrent flamer with Ignores Cover and Twin-linked, modelled. Burning Spray (strips cover) is noted and worth nothing on our table; Deadly Demise is not counted. Harvester: in Assimilation Swarm, each Harvester unit regenerates one unit within 6" in each Command phase (wounds back, a model back, or 3 for an Endless Multitude). tiertest.js credits this as a lend capped at 38.4 pts for every Harvester at every size. The lists' use: 2 or 3 models (sizes 2:4, 3:3) beside the Norn Assimilator, Hive Tyrant and Biovores, in Assimilation Swarm with Talons of the Norn Queen. They field durable Harvesters with an Overwatch flamer, not cheap action bodies.

Regeneration's worth (EV.healLift) on the squads the lists put beside them: Neurotyrant 102 pts, Neurolictor 71, Hormagaunts 61, Hive Tyrant 42, Norn Assimilator 29, Biovores 16.

Verdict: a quantity measured badly. The cap gives a 30-pt Ripper Swarm and a 40-pt Pyrovore the same lend, whatever they heal. Change: P1. It holds under any tie order; P1b's partner flips between three squads with 3 lists each. It moves Ripper Swarms −19.1 (B → C; their co-listed squads, from 1 list, gain little); no other composite moves. Two engine notes. A lone Pyrovore dies before its 12" gun reaches range (its damage per point is a seventeenth of two models'). And P2 shows why the lists field 2 or 3: a lone Harvester's lend should end when it dies. Next test: P1 with P2 at the lists' size.

Tyranid Warriors with Ranged Bio-Weapons (60 pts / 3; Auspex C, 1 list)

Check. T5, 4+, W3, OC 2 a model, Synapse; devourers by default (venom cannon or strangler, 1 per 3, isn't in the table). Adaptable Predators (shoot and charge after Falling Back) is noted. Data bug: build/units.json gives them Stealth, as it does the Melee Warriors, Venomthropes and Genestealers. The 11th-edition datasheet has none: BSData hides the link unless the attached leader takes the Chameleonic enhancement. docs/bsdata.js:986 collects rule links without reading hidden modifiers (its Fights First check, line 1065, does). The live rankings show a "stealth" trait; the tier test doesn't read it.

Why B with 1 list: Anvil (OC 6 for 60 pts, the 87th percentile), and nothing else.

Verdict: size, no change of its own. With all ten on they were scored as 6 with a Prime (A); at the listed 3 they are C. W2 also reaches C, but costs 2 within one.

4. Bugs and gaps

1. Data, live: docs/bsdata.js:986 ignores hidden modifiers on rule links. A leader's enhancement (Chameleonic) becomes unconditional Stealth on four Tyranid units in the rankings' Utility; other armies' conditional links are likely affected.
2. Data: Neurogaunts' larger size is 21 models in build/units.json; the datasheet has 22.
3. Engine: Feed the Swarm is a flat 38.4 pts per Harvester, blind to the squad healed and to the Harvester's survival.
4. Engine: absolute survival drives size: a lone short-ranged walker delivers almost nothing (Pyrovores ×17 from 1 to 2 models), and the same effect makes bestSize pick the largest size.
5. Not modelled: Stealth, Fights First, Spirit Leech, Burning Spray, Deadly Demise.

5. Method

The scratch bench is tools/tierbench.js plus the size switches, a per-row hook and per-row multipliers (hits to destroy, Hammer, Anvil), applied to pool and Tyranid rows alike. Stealth comes from build/units.json without the four false Tyranid entries. Co-listing and sizes come from reports/tiers/2026-10-02-tyranids-colist.json and -sizes.json.