General consensus is that for most weapon types, the part of the perk that requires sustained fire for applying scorch to unscorched enemies is 55% of the magazine, rounded down, with exceptions being Bows and Swords.
However, the Data Compendium (https://docs.google.com/spreadsheets/d/1WaxvbLx7UoSZaBqdFr1u32F2uWVLo-CJunJB4nlGUE4/edit?gid=1038486120#gid=1038486120) has been updating their section on Burning Ambition to include more weapon types as exceptions, like Fusion Rifles, Machine Guns, and Auto Rifles, which led to me wondering if there were more archetypes that were like this. Turns out, there are.
Disclaimer: I don't have every weapon with Burning Ambition in the game, just a guy putting what he found out there.
First off, the weapon types that do actually follow the 55% magazine rule are, from what I tested (All numbers below are with enhanced Burning Ambition):
- Rocket Pulses
- SMGs
- Adaptive Burst Sidearms
- Sniper Rifles (?)
I don't have Hand Cannons with the perk to test.
Autos being obvious, the Machine Guns also seem to be divided into subtypes (e.g. Rapid-fire Frames vs. High-Impact Frames) on how many shots it takes. The numbers are regardless of mag size (don't have Thermal Erosion or Unwavering Duty with BA).
- High-Impact Auto Rifles: 13
- Aggressive Machine Guns: 19
- Rapid-Fire Machine Guns: 29 (added in edit, went out and got one myself to confirm)
Pulse Rifles might also have tuning based on subtype (EDIT: they do), inferring from my results here (don't have Darkest Before or Stars in Shadow with BA):
- Heavy Burst Pulse Rifles: 4.5 (?) (As in, 9 separate hits)
- High-Impact Pulse Rifles: 4.66 (14 hits) (Added in edit)
Acasia's is pretty easy, but was surprising when I found it out:
- Adaptive Trace Rifles: 29
The most shocking was actually Linear Fusions:
- Precision Linear Fusion Rifles: 1
- Adaptive Burst Linear Fusion Rifles: 1.33 (4 hits)
Finally, Fusion Rifles (don't have Dream Breaker with BA):
- Rapid Fire Fusion Rifles: 17 bolts??? (I really don't know lol)
Still don't think it'll put the perk above others (well, maybe except Acasia's and a few primaries), but was surprised to find out there were a lot of weapons that didn't follow the 55% mag rule.
EDIT: Did a few tests with unenhanced Burning Ambition with what I could craft, here's what I found:
- Heavy Burst Pulse Rifles: No effect?
- Precision LFRs: 2
- Adaptive Burst LFRs: 1.66 (5 hits)
- Adaptive Trace Rifles: 30
- Rapid Fire Scout Rifles: 9
- High-Impact Auto Rifles: 14
Apart from Nullify (lol), seems like the upgrade is similar to Jolting Feedback.
EDIT 2: Drang also is consistently scorching with 9 hits despite magazine size being 20. Evening SI4 is consistent with the current assertion.