pilot: real ballistics from the solved Shell records — and the metric that says it did not help

Shell_TCAF_DeltaSaber_*_P: Velocity 8000, LifeTime 0.5 s, MaximumRange 4000
(self-consistent: 8000 x 0.5 = 4000), all confirmed. Two things were wrong:
lead computed flight time as d / OUR speed (400-2000 u/s, so every shot was led
4-16x too far), and FIRE_RANGE was 5000 — past where the shells expire.

Both fixed. But the HUD's own kill counters read 0000/0000 at the end of EVERY
run including the nearest-fighter baseline, so the pilot kills nothing in any
configuration and 'fraction of frames firing' was never measuring lethality.
No improvement is claimed.

One clean negative result kept: gating on the target's angular half-size alone
(2.7 deg at 2584 units) is far tighter than the steering loop can hold the nose
— firing collapsed to 1 frame in 2639. Angular size is a floor on the firing
cone, never a cap.

Next: the HUD carries a live ammo count, so holding fire and watching it settles
'we never shoot' vs 'we shoot and miss' in a single run.

docs/re/mission-escort-state.md

@@ -121,6 +121,37 @@ destroyer the avoidance expected to clear by 365 units — against a hull of rad
 `BIG_RADIUS` now gets a physical keep-out of **its own radius + 800**, with braking
 inside it, whatever its faction; the next run survived its full 330 s untouched.
 
+## Ballistics from the disc data — and the measurement that invalidates the metric
+
+The solved `Shell` records give the player's guns exactly
+(`Shell_TCAF_DeltaSaber_{NoseGun,Gun,Beam}_P`, all ✅ CONFIRMED):
+**`Velocity` 8000**, **`LifeTime` 0.5 s**, **`MaximumRange` 4000** — self-consistent,
+since 8000 × 0.5 = 4000 — plus shell `Radius` 20–30 and `Power` 15/30/40.
+
+Two things in `pilot.py` were plainly wrong against those numbers, and both are fixed:
+
+- **Lead used our own speed as the shell speed.** Flight time was `d / max(our_speed,
+  300)`, i.e. 400–2000 u/s instead of 8000 — every shot led **4–16× too far ahead**.
+- **`FIRE_RANGE` was 5000**, past the range at which the shells expire.
+
+**But the outcome metric says none of this has been shown to help.** The HUD's own
+counters — `YOU KILLED: WARSHIPS` / `WARPLANES` — read **0000 / 0000 at the end of
+every run**, including the nearest-fighter baseline. The pilot is not killing
+anything in any configuration, so "fraction of frames with the guns on" (12 % → 5 % →
+1 frame in 2639 as the firing gate was varied) was never measuring lethality. The
+corrections above are right on the physics and fix demonstrably wrong code; **they are
+not evidence of improvement**, and none is claimed.
+
+The firing gate itself produced one clean result worth keeping: gating on the target's
+angular half-size **alone** (2.7° at 2584 units for a fighter) is far tighter than the
+steering loop can hold the nose, and firing collapsed to 1 frame in 2639. Angular size
+belongs in the gate as a **floor** that opens it up close, never as a cap.
+
+**Open (next):** find out why nothing dies. The cheap decisive test is whether the
+`RB` command discharges the gun at all — the HUD carries a live ammo count
+(`MAIN MPM 00300`, which the weapon RE matched to `LoadingCount`), so holding fire and
+watching that number settles "we never shoot" vs "we shoot and miss" in one run.
+
 ## Reimplementation notes
 
 - Defeat conditions for an escort stage are readable as: protected-asset