This is coming from someone who uses the dual/triple UAC/5 on every variant he can...
Don't use chain fire (where one fires after the other per click). Use linked fire where they go off simultaneously. Don't hold the button down, just fire a rhythm...click...click...click...click. You WILL jam. Just take it in stride and find cover.
You'll notice a few things: first, that if you fire them linked, you have a greater chance of all shots hitting the same place, and hence, more likely to destroy a particular spot. When they're chain fired, you're far more likely to spread your damage over multiple armor spots, taking more time to down a mech.
Second, If you're using UACs, don't think of yourself as an in your face brawler. Fire from cover until you jam, then get back under cover. This applies whether you're the AS7-D-DC or the Ilya Muromets.
Third, when it's really critical to fire a lot (like an Atlas is bearing down on you and there's no where to retreat), its okay to click faster to fire, but DO NOT hold the mouse button down, you'll jam fast.
Fourth, every once and a while (once or twice per drop on average, but sometimes you get lucky (the UAC is all about luck)), you'll get a lucky streak where you can easily fire 20 or 30 rounds in just a few seconds. It is SWEET to watch a fresh Atlas drop when this happens.
Fifth, the UACs, like all ACs, take practice. Learn to lead your target and to setup angles. ACs do not fire well while you're turning your feet. Better to head in a straight line perpendicular to your target then to try and out-turn them (as with light mechs circling you).
Sixth, use the IR view on all maps but Caustic (the 'H' key), at least when things are far away. Its very easy to snipe (and snipe well) with UACs. Don't forget to zoom ('Z').
Seventh, carry a lot of ammo. For the Atlas with dual UACs, I carry 8 tons of ammo (200 rounds). For the Ilya Muromets with triple UACs, I bring 9 nine. Occasionally, I run out of ammo, but I've gotten very good at shooting with the UACs.
Eight, learn to listen to your UACs. If you have dual/triple UACs, you can hear when one or more is jammed. Slow up your pace. UACs will jam more often when they fire at the exact same moment. The best situation to be in is when a previously jammed UAC unjams and starts firing a split-second after your other UACs...this is when it becomes very easy to rapid fire as in fourth, above.
The dual/triple UAC is my favorite weapon combination. I highly recommend it. It is not uncommon for me to get between 600 and 800 damage on my IM, and to break 1000 damage a round on my D-DC. UACs are not easy weapons, they take a fair amount of skill, but they can melt faces faster than you can power up your mech.
Edited by Haggle, 27 January 2013 - 11:15 PM.