I came up with this when playing around with my Black Widow. I really enjoy the 2xAC10, 4xML build on my Firebrand, and the extra tonnage plus a light engine allows for the MRM10 on the shoulder. 50 point alpha with decent pinpoint damage with the AC's and ML's. The Widow's quirks of energy heat & range also help.
I'm not sure I'd give up the MRM10 for 4.6 kph more speed. 80 shots from the AC10 is also likely overkill. ERML are a viable choice if you can manage the extra heat.
In my defense, using all tree of the weapon types is kind of complicated, with different face times and velocities, sticking to 2 is easier to get the hang of, plus it just seems like a last second kind of thing,plus it’s way cooler, faster and has slightly more ammo for a more aggressive play style fit for a cooler build
IMHO, MRM10 is the worse weapon in the game: lot of heat (seriously, if you take your original build and remove only the MRM10, you jump from 32% cooling efficiency to 37%, it generates more heat than a ML), weights too much and has very bad spread (so ok, it deals more damage, but the damage dealt is not meaningful for the final kill blow). Additional speed is never a waste because warhammer has very good acceleration, so a greater speed threshold means you can poke faster (from my experience, WHM-6R dual gauss + 4xERML is way better with XL300 rather than LE280 because of better speed). If you simply remove the MRM10, you gain: more cooling (heat stable if you fire only the 2xAC10 and you can safely swap ML for ERML which with maxed range skills should reach 450 meters optimal thanks to range quirks), +1 ton of ammo (swap for a TC1 if you feel 3 ton of ammo are enough, so you get a projectile speed bonus and most importantly +3.5% laser range). I've tried to fit a XL300 version, but there would be an unused half ton left, so the classic WHM-6R 2xAC10 + 4xERML would fit better despite the lack of energy range quirk. I'm still not sure if I would prefer this black widow to my 2xAC10 + 2xLL + XL300 (better range, better speed / pokes, very similar cooling, very slightly lower alpha strike, lower armor on shield arms) or the classic WHM-6R with 4xML mounted only on torsoes (and unluckily with no range quirks). My rule of thumb is to never drop lower than 35% cooling efficiency unless it's a build heavily focused on alpha strike: with 2xAC10, you should fit a build capable of sustaining fire for a long period of time, otherwise you are not "exploiting" the coolness and sustained DPS of autocannons.
Good points. I use the MRM10 as a way of boosting alpha damage. The usual weapon rotation is the AC10s and MLA's with me switching the MLA's to chain fire if I'm running hot. I prefer to have the 50 alpha damage with some crit potential if I get the drop on someone. Exclude the MRM10 from the firing rotation and the cooling efficiency stays at 37% as you stated. This is why I only carry 1 ton MRM ammo. I'm always leery of XL engines in heavies, especially with the introduction of Light engines. I think the only mech I use XL in at this point is my Jagermech Firebrand.
