Is Detonator with a Martial Gun going to be better than Slug with a new gun?
If not, the point stands.
The only reason EVER to use det is in a situation where your slug acc is too low to be practical. The point here isn't to compare Det vs other WS, it's to point out the importance of the fTP bonus on Detonator.
If you aren't using det, why would you care what gun is best for Det?
If you're talking about /ra, Martial was already one of the worst guns at that task (being saved only by TP Bonus). Your comparison does not account for the difference in TP damage between Martial and a superior gun in a ranged-attacking scenario.
Martial will still win if the boost in WS damage will overcome the loss in damage during the TP phase. This is why SAM have been using Hagun for ages.
TP damage is much less complicated than WS damage to compare. Looking at a WS + 6 shot to 100 TP senario,
Damage = (Gun + Ammo + fSTR) * rattk function
Going to assume a lower fSTR value since /ra only is done on higher level targets. Also, going to assume a cratio of 1.5 for similar reasons.
Martial: (39+70+10)*1.5 = 178
178 * 6 = 1068 Dmg TP phase
45 DMG gun: (45+70+10)*1.5 = 187
187 * 6 = 1122 Dmg TP phase
cratio of 2.5 to account for rattk bonus on det
Higher fSTR due to higher acc on det allowing racc -> STR swaps
745 Dmg WS
745 + 1068 = 1813 Damage for TP/WS cycle
45 Damage Gun: (45+70+15+25)*1.5*2.5
581 Dmg WS
581 + 1122 = 1703 damage for TP/WS cycle
So the damage increase from the WS compensates for lower TP phase damage.
Now to stipulate, what else is on that 45 Damage gun?
If you can get enough Store TP to drop a shot to WS then that can allow more WS/fight allowing more damage.
If you have a Magian gun with RACC or RATTK or Occ Deals Double Damage, that will impact the comparison also.
I just ran the numbers for a shooting only scenario with the + 10% Det damage Anarchy:
48 DMG gun: (48+70+10)*1.5 = 192
192 * 6 = 1152 Dmg TP phase
651 Dmg WS
651 + 1152 = 1803 damage for TP/WS cycle
That is almost equal with Martial. Considering the increase in damage on the occasional QD, looks like this would be a completely reasonable option.
So I'd say:
If you are melee -> WS
Don't use Det, use Slug Shot, but if you insist on Det, Martial will be the best option
If you are /ra only -> WS
If you use a DMG 45 gun, make sure it overcomes the fTP on martial, 48DMG +10% det will be equal with Martial. But Slug and Numbing will be superior to Det unless racc is super low.