The UAC20 is not a very desirable weapon in MWO. Its projectile is slow, meaning you can only hit targets coming directly at you and have some hope of accuracy. It also produces 5 of these slow bullets that has to be carefully aimed as they come out which takes a fairly long time. Meanwhile you're left vulnerable to return fire as you aim this bullet hose. On the other hand other UACs suffer less from this as their bullets are significantly faster while costing less tonnage, so they're more common on the battlefield than the oh-so-terrifying UAC20.
Why build a Warhawk with an UAC20 then? Making a squishy 'Mech like a Warhawk a brawler . . . with UAC20? Well, I did not dare do this before the Warhawk got a face-lift with new quirks. Most of my Warhawk builds were either pure laser boats or had a combination of lasers and missiles. However the new Warhawks quirks bring quite impressive ballistic bonuses with them. The WHK-A right arm comes with a -10% ballistic cooldown reduction, LBX spread reduction and a very tempting -30% UAC jam change reduction on top of sporting +28 armor. The WHK-B left arm is a bit disappointing in comparison, but it comes with a further -10% ballistic cooldown reduction. On the other hand, all of the WHKs got substantial movement quirks in the form of acceleration, torso twist range/turn rate and 'Mech turn rate. It almost handles like a medium.
Well, what to do with these quirks? Some people instantly switched to dual Gauss builds to take advantage of a potential 32% total cooldown reduction (with the Gauss cooldown module). Though, when I looked at the quirks I instantly knew I had to check out the UAC20. I experimented a lot with it on my Summoner and while I had good success, I felt like it was jamming way too much to be useful.
When a UAC jams, you wait 5 seconds AND an additional cooldown cycle. So, if an UAC20 without any quirks or modules jammed before, you had to wait a whopping 9 (5 jam+4 cooldown) seconds to be able to use it again. Well, think about it. You're in a massive brawl against a Dire/Atlas and you lose your primary weapon for 10 seconds. It's not pretty and usually results in a painful death accompanied by "FFS WHY WON'T YOU FIRE!" cries.
The UAC jam chance reduction changes everything. It brings down the jam chance 30%, meaning the effective jam chance goes down from 17% to 11.9%. That's a lot more less jams. The UAC20 suddenly becomes tempting due to its sheer damage output potential despite its disadvantages.
With these in mind, I set out to build a WHK build centered on the UAC20. Here's what I came up with:
While the UAC20 has the main focus, it is also accompanied by two secondary weapons. The SRMs are there to help you augment that massive DPS of the UAC and are especially useful in situations when you're heat capped. They offer a lot of damage for cheap tonnage and low heat. The other secondary is that 2xERLL arm. Most of the brawler builds lack punch at range and are helpless against opponents poking them. ERLLs allow you to return a lot of damage in kind while being equally useful in brawls. Normally I wouldn't even think about ERLLs for my brawlers due to their obscene burn time, but since we already have a lot of face-time with the UAC20, it makes sense to bring them. The UAC20 has 4 tons of armor, while the SRMs only have 2. You can take off two extra heatsinks to adjust the ammo if necessary, but I feel like this strikes a good balance. If you manage to deplete your UAC20 ammo, you should be pulling at least 700+ damage with a bunch of kills anyway.
The results? I've been having an absolute blast with this thing. Funnily enough, it plays to the strenghts of the Warhawk; being a mobile assault with a devastating damage potential. Once you have that UAC20 chain going thanks to the jam reduction quirk, you will outtrade anything. The enemy can keep throwing 'Mechs at you and you'll just mow them down. Not even a dakka DWF with its bullet hose will be able to put you down before rip out their CT. I kept amazing myself with just how much damage/kills I got in very short engagements.
The reason this build does so well is because the mobility of the WHK synergizes well with the requirements of a proper UAC20 brawler. The UAC20 is devastating, but you need to be literally hugging your target to unleash its full potential. With a Dire you can't dictate range, you fight where the enemy engages you so it makes more sense to go for a generalist long range build. The WHK on the other hand has the speed and mobility to quickly bring the UAC20 to its opponents and chase them if necessary.
You have to be really careful piloting this thing though. The WHK is not a particularly tough 'Mech and your sides are especially vulnerable against surprise attacks from unknown directions. The timing and picking your engagements is the key here. You have to time your pushes such that you go in and engage a minimum number of enemies simultaneously. It's not different from how the other brawlers play. It's definitely hard to describe here, but you'll start getting a feeling for it as you get more experience in playing brawler builds.
I have put so many hours in this build (8+) that I can keep talking about it for a lot longer. Though in order to keep these build posts as concise as possible, I'll stop myself now. I'm just excited that I finally found a working build with an UAC20. Let me know what you think about the build in the comments.
While playing around with the build described above, I came up with an alternative build that downgraded the UAC while buffing the lasers. I did this because I wanted to balance the firepower on both sides as losing the UAC20 side pretty much means you're out of the fight. Two ERLLs might be laughable, but two LPLs are hardly anything to scoff at. Accomodating the LPLs require more than the downgrade to the UAC10 though and two extra heatsinks also had to be sacrificed.
It's safer and has better redundancy, but I just didn't get the feeling that I was "wrecking" my opponents with this. Still, check it out and see if it suits better to you.